DECONTAMINATION OF PESTICIDE RESIDUES ON FRUITS AND VEGETABLES
The effect of household preparation or commercial processing to minimize the pesticide residue levels on raw agricultural commodities (RACs) is considerable as they typically decline the residues. These kinds of processung strudies are intended: To provide data on the transfer of residues from the RAC towards the processed merchandise, in an effort to calculate reduction aspect or concentration factors; To allow and much more realistic estimate to be made of the dietary intake of pesticide residues; To establish MRLs for residues in processed products where essential, in line with needs of national regulatory authorities or international requirements. Preferably, RAC samples used in processing studies should contain field treated quantifiable residues as close as possible towards the MRL, so that measurable residues are obtained, and transfer factors for the a variety of processed commodities may be determined. A transfer factor gives the ratio on the residue concentration inside the processed commodity to that in the RAC. For example if the residue concentration is 0.5 mg/kg in olives and 0.2 mg/kg in olive oil, the transfer aspect is 0.2/0.5=0.four. A factor 1 (= concentration factor) indicates a concentration effect on the processing procedures. Enhancing the residues either by escalating the application prices, shortening the pre-harvest interval (PHI) or spiking the RAC together with the active ingredient and its metabolites in vitro isn't, as and rule, desirable. Spiking is only acceptable when the RAC residues may be shown to consist only of surface residues. However, in some situations, particularly exactly where residues inside the RAC are close towards the analytical limit of determination, field therapy at exaggerated prices or shortened PHIs is advisable to get sufficient residue levels for the processing studies.
The first step in household or industrial meals processing is the preparation of meals utilizing a variety of mechanical processes, like removing broken or soiled products or parts of crops, washing, peeling, trimming or hulling. This often results in considerable declines in the amount of pesticide residues within the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).
WASHING
Household washing procedures are typically carried out with operating or standing water at moderate temperatures. Detergents, chlorine or ozone could be added for the wash water to enhance the effectiveness in the washing procedure (Ong et al., 1996). If required, a number of washing measures might be conducted consequently. The effects rely around the physiochemical properties from the pesticides, like water solubility, hydrolytic price continual, volatility and octanol-water partition coefficient (Pow), in conjunction using the actual physical location of the residues; washing processes lead to reduction of hydrophilic residues that are positioned around the surface in the crops. Furthermore, the temperature in the washing water and the type of washing has an influence around the residue level. As pointed out by Holland et al. (1994), hot washing along with the addition of detergents are far more effective than cold water washing. Washing coupled with gentle rubbing by hand below tap water for 1 min dislodges pesticide residues significantly (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues will not be removed drastically by washing. Table (1) shows examples in the effects of washing around the residue levels of various pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables typically contain residues of pesticides applied during the developing season. As a result, peeling or trimming procedures decrease the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables having a knife is typical household practice. Numerous examples show that most of the residues concentration is positioned in or on the peel. Peeling on the RACs may remove greater than 50% in the pesticide residues present in the commodity. As a result, removal from the peel achieves practically complete removal of residues, so leaving tiny in the edible portions. This is particularly crucial for fruits that are not eaten with their peels, such as bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot reduced the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer element of 0.2. Nonetheless, the peel from industrial peeling processes may be employed as animal feed or for the production of vital oils (citrus) or pectin (citrus, apple and so on.). For such industrial processes, it really is important to realize that especially non-systemic surface residues are usually concentrated within the peel. For systemic pesticides, peeling may not be as powerful as shown by Sheikhorgan et al (1994). After application of thiometon on cucumbers, no reduction of residue levels could possibly be detected within the peeled cucumbers. Under the Codex Alimentarius, as in other international standards, MRLs refer to the entire fruits, that is proper for assessing compliance with GAP. These MRLs are of limited significance, nevertheless, in assessing dietary exposure to pesticides from fresh fruits, that are peeled (Holland et al.,1994).
COOKING Cooking procedures at distinct temperatures, the duration in the process, the quantity of water or meals additives, as well as the variety of technique (open or closed) may have an impact around the residue level. Usually, residues are reduced in the course of the cooking method by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Several research have been reported around the dissipation of pesticides in crops during cooking. Furthermore to the studies summarized in table 1 the behavior on the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos during cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased throughout the cooking procedure corresponding to the boiling time. In accordance with their water solubility, some pesticides had been translocated in the raw components in to the cooking water. Alternatively, the pesticide remained inside the processed meals in line with their octanol-water partition coefficient, which can be an indicator of hydrophilic or lipophilic properties on the compound. In exceptional cases, cooking processes may cause pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which is considerably a lot more potent than the parent compound (Leparulo-Lofus et al.,1992). Another example would be the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, for the duration of heating processes (Petersen et al., 1996).
Dipping in chemical answer Sodium chloride solution is largely utilised to decontaminate the pesticide residues from distinct fruits and vegetables .there are many studies to prove the efficacy of salt water washing to dislodge the pesticides from crops. In this approach, sample of chopped fruits and vegetables is place in a beaker containing 5% sodium chloride resolution. Right after 15 minutes the plant samples are gently rubbed by hand in salt answer and alt water is decanted. The examples on the impact of salt answer treatment on the residue levels of distinct pesticides applied to vegetables happen to be shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt resolution for ten minute followed by water wash prove to become effective, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and five days soon after spray of triazophos (700g a.i./ha) although the acephate residues have been removed to an extent of 78.95% at zero day. Following exact same strategy Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days right after spraying of cypermethrin in chillies. Dip therapy of fruits in NaCl remedy, HCl, acetic acid, NaOH answer, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids compared to 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water solution of NaOH, acetic acid potassium dichromate and soap resolution utilised as decontaminating agents for tom . The remedy of fruits with 2% tamarind solution dip for 5 minute followed by tap water wash and steam cooking for ten min. was identified to get rid of the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, one hundred and 100% respectively. Therapy with 2% salt remedy was equally powerful. Dip remedies from the brinjal fruit wioth water, sodium chloride, HCl resolution, acetic acid answer or potassium permanganate answer had been all found to eliminate 30-33% in the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH answer 40-45% and Teepol (a detergent) answer 50-60%. The impact of washing in reducing the residues decreased progressively at the second and third harvests. A lot of experiments had been carried out with all the 3 frequent household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in lowering the pesticide residues in various vegetables. The results happen to be summarized within the following table.
Table: Effect of washing, salt water washing and cooking on pesticide residue levels.
Crop Pesticide % of Residue dislodged *ResultReference Washing with waterSalt water washing Cooking CauliflowerMethamidophos41-4846-4746.94 -53.54Largest reduction was brought about by cooking. Jacob and Verma (1990)
Okra Methamidophos 64-72 19-58 58-64Washing with water could remove maximum residues indicating its maximum solubility in water although all of the processes reduce down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was found to become more effective than cooking most likely because of the thermal stability of cypermethrin.Malik et al (1997)
Cabbage
Chlorpyriphos
Quinalphos
38
41
52.13
56.50
54.three
55With the 3 processes residues have been decreased to some extent. They could not minimize the residue under the MRL. Hence a waiting period of a minimum of 1 and two weeks, respectively, was recommended irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)
Cow pea Metasystox
Carbalyl 84.3
87.five 86.four
88.7 83.4
80.8Only boiling of the pod samples could decontaminate the residues present of surface or inside the tissue for the extent of safe limits by 10th day of therapy.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was discovered to be most efficient and lowered the TMRL value from 1 week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Both washing with water and salt water washing brought down the residues beneath the MRL at zero days, cooking also did this resulting maximum reduction of residues. Jacob and Verma (1985)
Cabbage Malathion
Carbaryl
Pyrethroids 64.60
75.40
22.06 (av.) -
-
-
83.97
89.62
56.72 (av.) The extent of decontamination was higher because of cooking in comparison to washing for all insecticides. Bhatia and Verma (1994) Leaves and curds of cauliflower heads of cabbage and pods of Indian colza
Green beans
Methamidophos
DDT
Malathion
Carbaryl
65.71-77.67
71
96
52
-
-
-
-
80-88.88
52(cooked) 66 (pressure cooked)
99(cooked) 99(p.cooked)
77cooked 69(p.cooked)
Cooking dislodges maximum residues.
Water wash removed maximum DDT residues whereas cooking is powerful to get rid of malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
In the above table it might be said that cooking is most powerful to decrease the residues of different pesticides from different vegetables although in some circumstances washing with water was found to become effective to decrease the initial residues of pesticides and it has been identified that using the ageing of residues or with all the increase within the sampling days over therapies the impact of washing decreases to get rid of the toxicant for the exact same extent as that of samples collected instantly right after spray exactly where boiling or cooking is located to become efficient. One of the feasible reason for high percentage of removal of toxicant from instantly collected samples as most of the residues are present of the surface in the samples and therefore it truly is very simple to remove by easy washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). Together with the time elapsed the residues are migrated inside the deeper tissues or strongly adhere around the rough surface of some vegetables. Furthermore, the washing cannot lessen the residues for the protected level as when compared with boiling. You can find some studies exactly where all of the three culinary processes proved to be inefficient to minimize the residues beneath the MRL worth. Based on Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop will be decreased only to some extent by a variety of property processing methods like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the residence processes for decontaminating the treated cabbage may be because of the robust adsorption properties of quinalphos and chlorpyriphos.
Impact of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues had been detected in 97(40%) of mt 243 samples analyzed soon after following standard household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) soon after household preparation. These benefits indicate that residue level in most commodities are substantially decreased following household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai neighborhood markets and fortified with recognized concentrations of a variety of pesticides followed by decontamination study with diverse household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at distinct stages of 512 raw marketplace samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples have been removed resulting in residues properly under the toxicologically acceptable limits. A quick rinse in tap water reduces pesticide residues on many varieties of make (Krol et al., 2000). Rinsing removed residues for nine of the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos weren't removed. This study confirms that the water solubility of pesticides will not play a important function inside the observed decrease. The majority of pesticide residues appear to reside on the surface of produce where it really is removed by the mechanical action of rinsing. Earlier research from the effects of commercial and house preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early research showed residue reduction to become substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for industrial preparation and from 14 to 99+ % for property preparation with all the exception of parathion in spinach and broccoli, commercvial and property prewparation substantially decreased organophosphate residues, with all the reduction normally becoming in the higher 80 or 90% range. Carbamate residues have been reduced by 58 to 99+ % when the vegetables have been commercially processed but only by 11 to 92% in home preparation. A current study in Korea supports these earlier research (Lee and Lee, 1997). These authors discovered that 45% from the organophosphate residues had been eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Approaches of multiresidue analysis of pesticides in fruits and vegetables Analysis by gas chromatography
Nakamura et al (1994) created a method for multiresidue analysis of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan around the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test solution). Organophosphorus pesticides have been directly determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides have been measured by GC-ECD right after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm were 42.5-128.5%. the detection limits were 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue approach was utilized by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which had been extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic specific (GC-TSD) detection.
The technique utilized for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, certain pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) utilizing gas chromatography. Samples had been extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates have been digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which can be collected in an ethanolic remedy of copper acetate and diethanolamine to type a yellow complex. The absorbance of yellow item was determined spectrophotometrically at 435 nm. The typical recoveries and CVs of the 52 pesticides have been 72-118 and 1-20%, respectively at the spiking levels of 0.01-1 ppm. A equivalent sort of approach was also described by Kole et al (1998).
Krol et al (2000) used a multiresidue process for determination of 12 pesticides in vegetables exactly where samples had been extracted with 2 propanol and petroleum ether followed by washing with distilled water 3 instances. Final evaluation on the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a approach to figure out organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup over florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was carried out with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up over silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.
Employing GC-ECD, the efficiencies of acetonitrile and acetone to extract the eight pyrethroids from six fruits and vegetable samples have been compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the six fruit and vegetable samples. The ruggedness tests demonstrated further that the proposed technique is easy, precise with very good precision and suitable for multiresidue evaluation of pyrethroid in numerous agricultural products.
Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) within the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in chosen ion monitoring (SIM) mode had been determined by Torres et al (1995) following extraction by Matrix Solid Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% within the conc. range 0.5-10 g/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes. A multiresidue technique as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their key metabolites) in 7 fatty processed foods determined by automated gel permeation chromatography using a Biobeads SX3 column as well as a methylene chloride-cyclohexane (15 + 85) eluant after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD employing OV-1701 and DB-5 columns. Typical recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits had been amongst 0.005 and 0.040 mug/mL. Benefits were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic circumstances for separation and identification of the compounds were selected making use of two capillary columns of diverse polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up after ethyl acetate extraction (Balinova,1999). Trova et al (1999) performed liquid chromatographic determination of pesticide residues (which includes azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables right after extraction employing an ethyl acetate/n-hexane solvent method instead on the extensively employed methylene chloride. Recoveries as needed by 'Guidelines for residues monitoring in the European Union' were observed; the new solvent system may be regarded as as an option to halogenated compounds, hazardous for their toxicity and dangerous for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide range screening technique was proposed by Gelsomino et al (1997) for multiresidue evaluation of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural merchandise utilizing gas chromatography equipped with long, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues were extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries in the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg have been 70-108%. Limits of detection were significantly less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical approach employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an efficient and dependable multiresidue strategy for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues in a huge variety of vegetable samples in which samples have been extracted with acetonitrile, along with the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into 2 fractoions, the pesticide fractions were respectively purified by a 2-step minicolumn cleanup, the second fraction via silica gel minicolumn; initial fraction through the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative regular deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits of the pesticides have been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study of the matrix induced impact for 16 typical pesticides, most frequently found in monitoring research in tomato pepper and cucumber, making use of a basic multiresidue strategy with GC-ECD or NPD, with out a earlier cleanup step. Anomalously higher GC responses and subsequently very high recoveries for several pesticides inside the extracts had been obtained by a standard calibration with pesticide solution in ethyl acetate. A quicker, less efficient, environmentally safer supercritical fluid extraction (SFE) technique was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato making use of vegetable sample: anhydrous magnesium sulfate (five:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The chosen SFE situations have been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in 3 ml of ethyl acetate. Except for imidacloprid, which was not recovered below any from the assessed circumstances, pesticide recoveries were greater than 80%. A simplified approach is described by Chaput (1987) exactly where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to determine 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and 3 related metabolites in fruits and vegetables right after extraction on the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with higher chlorophyll and/or carotene content (e.g. cabbage and broccoli). Recovery information have been obtained by fortifying five distinct crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.five ppm. Recoveries averaged 93% at each fortification levels. The coefficient of variation of the method at each levels is
Estimation by GC-MS/LC-MS Because the mass spectrometer is capable of achieving higher levels of molecular specificity as when compared with the classic GC detectors and may be programmed to search for many hundred target ions, GC/MS will be a promising strategy for regulatory agencies to discover for monitoring pesticide residues in day-to-day food provide (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue method utilizing gas chromatography /mass spectrometry/selected ion monitoring (GC/MS/SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl and prothiophos residues in fruits and vegetables. Recoveries have been among 46 and 108% at the 0.5 mg/kg fortification level of every pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation were in between 0.7 and 19%, with an average of 7.5%. The estimated limits of detection from the pesticides inside the crops were 0.1-0.05 mg/kg, except that captan had limit of detection in the crops larger than 0.5 mg/kg. A strategy determined by solid-phase extraction using a carbograph 1 cartridge and reverse phase liquid chromatography /mass spectrometry (LC/MS) with an electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in 10 distinct varieties of fruits and vegetables .twelve carbamates added to vegetable supplies were extracted with methanol making use of a homogenizer followed by filtration , an aliquot in the homogenate equivalent to 5 g in the vegetable material was suitably diluted with water and passed via a 1 Carbograpg 1 extraction cartridge. Carbamates were eluted by passing by means of the cartridge 6 ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery on the analytes was much better than 80%, irrespective on the sort vegetable matrix to which the analytes had been added. A technique utilizing totally automated solid-phase extraction (SPE) sample cleanup and on-line liquid chromatographic evaluation with UV and fluorescence detection in tandem for determination of carbendazim and thiabendazole in different crops was reported by Hiemstra et al (1995). A total of 199 pesticides were determined by Fillion et al (1995) in fruits and vegetables using acetonitrile as extracting solvent along with a miniaturized charcoal-celite column cleanup followed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Carbamates were analyzed by liquid chromatography with post column reaction and fluorescence detection. Recovery data had been obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) employed a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric stress chemical ionization mass spectrometry (LC-APCI-MS) approach for the simultaneous analysis of dithiocarbamates and their degradation merchandise in crops. Average recoveries varied from 33 to 109%, and relative common deviation was among four and 21% with limits of quantification ranged from 0.25 to two.5 mg/kg. A multiresidue analysis for the determination on the 101 pesticides, like organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Analysis was performed inside the selected-ion monitoring mode. Samples had been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% from the pesticides wee amongst 70 and 110%; even so, the recoveries of acephate and folpet had been quite poor, i.e.,
Proposed program of work Standardisation of multiresidue analytical methods of pesticides
Analytical normal of selected pesticides belonging to diverse classes viz. OC (HCH (?,?,? and ? isomer), DDT (OP-DDT, PP-DDT, op-DDD, pp-DDE), Endosulfan (?,? and endosulfan sulfate) and dicofol);OP(Dimethoate, Malathion, Methyl parathion, Chlorpyriphos, Quinalphos, Triazophos, Phosphamidon,Dichlorvos Metasystox and Monocrotophos) and Synthetic Pyrethroids (Cypermethrin, Deltamethrin, Fenvalerate) for monitoring and decontamination studies have been collected from various sources as follows: Sl No.Name on the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA two?-HCH99.5EPA three?-HCH99.5EPA four?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel ten?-endosulfan99.0Excel 11endosulfan sulfate99.0Excel 12Dicofol96.0Bayer Organophosphorus 13Dimethoate96.5UPL 14Malathion97.3UPL 15Methyl parathion98.5Bayer 16Chlorpyriphos99.7Denocil crop protection Ltd. 17Quinalphos95.6Sandoz Ltd. 18Phosphamidon93.9Bayer 19Triazophos40.8Aventis Crop Science 20Monocrotophos77.0UPL 21Dichlorvos- 22Metasystox- Synthetit pyrethroids CCSRI Cypermethrin,99.0CCSRI Deltamethrin
Fenvalerate99.0
99.0CCSRI
4.1.1Stock common solution: Stock normal solution of various pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as working regular and to check the mindividual chromatographic peaks for their suitability for multiresidue evaluation. 4.1.2Preparation of mixed common solytion: in the individual regular solutions a mixed common resolution is usually to be ready for approach mdevelopment and decontamination studies. four.1.3Extraction and cleanup In the review of literature three strategies proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) happen to be selected to conduct the extraction and cleanup process where both the liquid-liquid along with a solid-phase extraction having a cartridge column will likely be compared to create a quick,easier and cost-effective technique to screen a wide range of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) is usually to be utilized for estimation on the pesticide residues. The operating situations will also be studied as stated within the chosen 3 techniques. 4.1.5standardisation on the mathod: The selected method wil be standardized by conducting a recovery study using the mixed regular by spiking inside the fruits and vegetables. four.2Monitoring of pesticide residues: 4.2.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling location: From two reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: Once in every single month for 1 year. Volume of sample: 1 kg of every single sample. 4.2.2pesticide residues to be monitored: Each of the pesticides listed in table two. four.3Decontamination research The pesticides are to become chosen on the basis of their greater use pattern in W.B. the sa]elected pesticides are listed as follows: OC (?-endosulfan, ?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyriphos, Quinalphos, Dimethoate, Triazophos, Malathion, Methyl parathion, phosphamidon, monocrotophos, metasystix; Synthetic pyrethroids: Cypermethrin, Deltamethrin and Fenvalerate. four.3.1Decontamination processes to become followed: 4.three.1.1Washing with water: Chopped samples will likely be taken in a tray containing water and the material will be gently rubbed with water for about one minute along with the water will likely be decanted or it's rinsed below operating tap water for 130 sec., with gentle rotation by hand . washing is usually to be repeated twice or thrice. 4.3.1.2Salt water washing: Chopped samples is going to be dipped within a beaker containing 2% or 55 sodium chloride answer. After 10-15 minutes the plant samplws will probably be gently rubbed by hand in salt answer and salt water is going to be decanted. Then the samples will likely be washed in water. 4.3.1.3 Boiling/Cooking: Unwashed samples wil be chopped and boiled inside a beaker till the water is totally evaporated covering the containr with or without having lid. Samples is usually to be permitted to cool. four.three.1.4 Mixture in the above strategies like soak in water for 15 min., rinse with water, cut into pieces and boiled in water 4.three.1.5Wash with soap resolution, rinse with water.
The effect of household preparation or commercial processing to minimize the pesticide residue levels on raw agricultural commodities (RACs) is considerable as they typically decline the residues. These kinds of processung strudies are intended: To provide data on the transfer of residues from the RAC towards the processed merchandise, in an effort to calculate reduction aspect or concentration factors; To allow and much more realistic estimate to be made of the dietary intake of pesticide residues; To establish MRLs for residues in processed products where essential, in line with needs of national regulatory authorities or international requirements. Preferably, RAC samples used in processing studies should contain field treated quantifiable residues as close as possible towards the MRL, so that measurable residues are obtained, and transfer factors for the a variety of processed commodities may be determined. A transfer factor gives the ratio on the residue concentration inside the processed commodity to that in the RAC. For example if the residue concentration is 0.5 mg/kg in olives and 0.2 mg/kg in olive oil, the transfer aspect is 0.2/0.5=0.four. A factor 1 (= concentration factor) indicates a concentration effect on the processing procedures. Enhancing the residues either by escalating the application prices, shortening the pre-harvest interval (PHI) or spiking the RAC together with the active ingredient and its metabolites in vitro isn't, as and rule, desirable. Spiking is only acceptable when the RAC residues may be shown to consist only of surface residues. However, in some situations, particularly exactly where residues inside the RAC are close towards the analytical limit of determination, field therapy at exaggerated prices or shortened PHIs is advisable to get sufficient residue levels for the processing studies.
The first step in household or industrial meals processing is the preparation of meals utilizing a variety of mechanical processes, like removing broken or soiled products or parts of crops, washing, peeling, trimming or hulling. This often results in considerable declines in the amount of pesticide residues within the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).
WASHING
Household washing procedures are typically carried out with operating or standing water at moderate temperatures. Detergents, chlorine or ozone could be added for the wash water to enhance the effectiveness in the washing procedure (Ong et al., 1996). If required, a number of washing measures might be conducted consequently. The effects rely around the physiochemical properties from the pesticides, like water solubility, hydrolytic price continual, volatility and octanol-water partition coefficient (Pow), in conjunction using the actual physical location of the residues; washing processes lead to reduction of hydrophilic residues that are positioned around the surface in the crops. Furthermore, the temperature in the washing water and the type of washing has an influence around the residue level. As pointed out by Holland et al. (1994), hot washing along with the addition of detergents are far more effective than cold water washing. Washing coupled with gentle rubbing by hand below tap water for 1 min dislodges pesticide residues significantly (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues will not be removed drastically by washing. Table (1) shows examples in the effects of washing around the residue levels of various pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables typically contain residues of pesticides applied during the developing season. As a result, peeling or trimming procedures decrease the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables having a knife is typical household practice. Numerous examples show that most of the residues concentration is positioned in or on the peel. Peeling on the RACs may remove greater than 50% in the pesticide residues present in the commodity. As a result, removal from the peel achieves practically complete removal of residues, so leaving tiny in the edible portions. This is particularly crucial for fruits that are not eaten with their peels, such as bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot reduced the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer element of 0.2. Nonetheless, the peel from industrial peeling processes may be employed as animal feed or for the production of vital oils (citrus) or pectin (citrus, apple and so on.). For such industrial processes, it really is important to realize that especially non-systemic surface residues are usually concentrated within the peel. For systemic pesticides, peeling may not be as powerful as shown by Sheikhorgan et al (1994). After application of thiometon on cucumbers, no reduction of residue levels could possibly be detected within the peeled cucumbers. Under the Codex Alimentarius, as in other international standards, MRLs refer to the entire fruits, that is proper for assessing compliance with GAP. These MRLs are of limited significance, nevertheless, in assessing dietary exposure to pesticides from fresh fruits, that are peeled (Holland et al.,1994).
COOKING Cooking procedures at distinct temperatures, the duration in the process, the quantity of water or meals additives, as well as the variety of technique (open or closed) may have an impact around the residue level. Usually, residues are reduced in the course of the cooking method by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Several research have been reported around the dissipation of pesticides in crops during cooking. Furthermore to the studies summarized in table 1 the behavior on the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos during cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased throughout the cooking procedure corresponding to the boiling time. In accordance with their water solubility, some pesticides had been translocated in the raw components in to the cooking water. Alternatively, the pesticide remained inside the processed meals in line with their octanol-water partition coefficient, which can be an indicator of hydrophilic or lipophilic properties on the compound. In exceptional cases, cooking processes may cause pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which is considerably a lot more potent than the parent compound (Leparulo-Lofus et al.,1992). Another example would be the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, for the duration of heating processes (Petersen et al., 1996).
Dipping in chemical answer Sodium chloride solution is largely utilised to decontaminate the pesticide residues from distinct fruits and vegetables .there are many studies to prove the efficacy of salt water washing to dislodge the pesticides from crops. In this approach, sample of chopped fruits and vegetables is place in a beaker containing 5% sodium chloride resolution. Right after 15 minutes the plant samples are gently rubbed by hand in salt answer and alt water is decanted. The examples on the impact of salt answer treatment on the residue levels of distinct pesticides applied to vegetables happen to be shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt resolution for ten minute followed by water wash prove to become effective, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and five days soon after spray of triazophos (700g a.i./ha) although the acephate residues have been removed to an extent of 78.95% at zero day. Following exact same strategy Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days right after spraying of cypermethrin in chillies. Dip therapy of fruits in NaCl remedy, HCl, acetic acid, NaOH answer, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids compared to 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water solution of NaOH, acetic acid potassium dichromate and soap resolution utilised as decontaminating agents for tom . The remedy of fruits with 2% tamarind solution dip for 5 minute followed by tap water wash and steam cooking for ten min. was identified to get rid of the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, one hundred and 100% respectively. Therapy with 2% salt remedy was equally powerful. Dip remedies from the brinjal fruit wioth water, sodium chloride, HCl resolution, acetic acid answer or potassium permanganate answer had been all found to eliminate 30-33% in the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH answer 40-45% and Teepol (a detergent) answer 50-60%. The impact of washing in reducing the residues decreased progressively at the second and third harvests. A lot of experiments had been carried out with all the 3 frequent household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in lowering the pesticide residues in various vegetables. The results happen to be summarized within the following table.
Table: Effect of washing, salt water washing and cooking on pesticide residue levels.
Crop Pesticide % of Residue dislodged *ResultReference Washing with waterSalt water washing Cooking CauliflowerMethamidophos41-4846-4746.94 -53.54Largest reduction was brought about by cooking. Jacob and Verma (1990)
Okra Methamidophos 64-72 19-58 58-64Washing with water could remove maximum residues indicating its maximum solubility in water although all of the processes reduce down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was found to become more effective than cooking most likely because of the thermal stability of cypermethrin.Malik et al (1997)
Cabbage
Chlorpyriphos
Quinalphos
38
41
52.13
56.50
54.three
55With the 3 processes residues have been decreased to some extent. They could not minimize the residue under the MRL. Hence a waiting period of a minimum of 1 and two weeks, respectively, was recommended irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)
Cow pea Metasystox
Carbalyl 84.3
87.five 86.four
88.7 83.4
80.8Only boiling of the pod samples could decontaminate the residues present of surface or inside the tissue for the extent of safe limits by 10th day of therapy.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was discovered to be most efficient and lowered the TMRL value from 1 week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Both washing with water and salt water washing brought down the residues beneath the MRL at zero days, cooking also did this resulting maximum reduction of residues. Jacob and Verma (1985)
Cabbage Malathion
Carbaryl
Pyrethroids 64.60
75.40
22.06 (av.) -
-
-
83.97
89.62
56.72 (av.) The extent of decontamination was higher because of cooking in comparison to washing for all insecticides. Bhatia and Verma (1994) Leaves and curds of cauliflower heads of cabbage and pods of Indian colza
Green beans
Methamidophos
DDT
Malathion
Carbaryl
65.71-77.67
71
96
52
-
-
-
-
80-88.88
52(cooked) 66 (pressure cooked)
99(cooked) 99(p.cooked)
77cooked 69(p.cooked)
Cooking dislodges maximum residues.
Water wash removed maximum DDT residues whereas cooking is powerful to get rid of malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
In the above table it might be said that cooking is most powerful to decrease the residues of different pesticides from different vegetables although in some circumstances washing with water was found to become effective to decrease the initial residues of pesticides and it has been identified that using the ageing of residues or with all the increase within the sampling days over therapies the impact of washing decreases to get rid of the toxicant for the exact same extent as that of samples collected instantly right after spray exactly where boiling or cooking is located to become efficient. One of the feasible reason for high percentage of removal of toxicant from instantly collected samples as most of the residues are present of the surface in the samples and therefore it truly is very simple to remove by easy washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). Together with the time elapsed the residues are migrated inside the deeper tissues or strongly adhere around the rough surface of some vegetables. Furthermore, the washing cannot lessen the residues for the protected level as when compared with boiling. You can find some studies exactly where all of the three culinary processes proved to be inefficient to minimize the residues beneath the MRL worth. Based on Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop will be decreased only to some extent by a variety of property processing methods like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the residence processes for decontaminating the treated cabbage may be because of the robust adsorption properties of quinalphos and chlorpyriphos.
Impact of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues had been detected in 97(40%) of mt 243 samples analyzed soon after following standard household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) soon after household preparation. These benefits indicate that residue level in most commodities are substantially decreased following household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai neighborhood markets and fortified with recognized concentrations of a variety of pesticides followed by decontamination study with diverse household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at distinct stages of 512 raw marketplace samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples have been removed resulting in residues properly under the toxicologically acceptable limits. A quick rinse in tap water reduces pesticide residues on many varieties of make (Krol et al., 2000). Rinsing removed residues for nine of the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos weren't removed. This study confirms that the water solubility of pesticides will not play a important function inside the observed decrease. The majority of pesticide residues appear to reside on the surface of produce where it really is removed by the mechanical action of rinsing. Earlier research from the effects of commercial and house preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early research showed residue reduction to become substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for industrial preparation and from 14 to 99+ % for property preparation with all the exception of parathion in spinach and broccoli, commercvial and property prewparation substantially decreased organophosphate residues, with all the reduction normally becoming in the higher 80 or 90% range. Carbamate residues have been reduced by 58 to 99+ % when the vegetables have been commercially processed but only by 11 to 92% in home preparation. A current study in Korea supports these earlier research (Lee and Lee, 1997). These authors discovered that 45% from the organophosphate residues had been eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Approaches of multiresidue analysis of pesticides in fruits and vegetables Analysis by gas chromatography
Nakamura et al (1994) created a method for multiresidue analysis of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan around the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test solution). Organophosphorus pesticides have been directly determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides have been measured by GC-ECD right after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm were 42.5-128.5%. the detection limits were 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue approach was utilized by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which had been extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic specific (GC-TSD) detection.
The technique utilized for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, certain pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) utilizing gas chromatography. Samples had been extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates have been digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which can be collected in an ethanolic remedy of copper acetate and diethanolamine to type a yellow complex. The absorbance of yellow item was determined spectrophotometrically at 435 nm. The typical recoveries and CVs of the 52 pesticides have been 72-118 and 1-20%, respectively at the spiking levels of 0.01-1 ppm. A equivalent sort of approach was also described by Kole et al (1998).
Krol et al (2000) used a multiresidue process for determination of 12 pesticides in vegetables exactly where samples had been extracted with 2 propanol and petroleum ether followed by washing with distilled water 3 instances. Final evaluation on the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a approach to figure out organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup over florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was carried out with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up over silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.
Employing GC-ECD, the efficiencies of acetonitrile and acetone to extract the eight pyrethroids from six fruits and vegetable samples have been compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the six fruit and vegetable samples. The ruggedness tests demonstrated further that the proposed technique is easy, precise with very good precision and suitable for multiresidue evaluation of pyrethroid in numerous agricultural products.
Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) within the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in chosen ion monitoring (SIM) mode had been determined by Torres et al (1995) following extraction by Matrix Solid Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% within the conc. range 0.5-10 g/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes. A multiresidue technique as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their key metabolites) in 7 fatty processed foods determined by automated gel permeation chromatography using a Biobeads SX3 column as well as a methylene chloride-cyclohexane (15 + 85) eluant after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD employing OV-1701 and DB-5 columns. Typical recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits had been amongst 0.005 and 0.040 mug/mL. Benefits were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic circumstances for separation and identification of the compounds were selected making use of two capillary columns of diverse polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up after ethyl acetate extraction (Balinova,1999). Trova et al (1999) performed liquid chromatographic determination of pesticide residues (which includes azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables right after extraction employing an ethyl acetate/n-hexane solvent method instead on the extensively employed methylene chloride. Recoveries as needed by 'Guidelines for residues monitoring in the European Union' were observed; the new solvent system may be regarded as as an option to halogenated compounds, hazardous for their toxicity and dangerous for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide range screening technique was proposed by Gelsomino et al (1997) for multiresidue evaluation of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural merchandise utilizing gas chromatography equipped with long, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues were extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries in the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg have been 70-108%. Limits of detection were significantly less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical approach employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an efficient and dependable multiresidue strategy for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues in a huge variety of vegetable samples in which samples have been extracted with acetonitrile, along with the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into 2 fractoions, the pesticide fractions were respectively purified by a 2-step minicolumn cleanup, the second fraction via silica gel minicolumn; initial fraction through the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative regular deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits of the pesticides have been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study of the matrix induced impact for 16 typical pesticides, most frequently found in monitoring research in tomato pepper and cucumber, making use of a basic multiresidue strategy with GC-ECD or NPD, with out a earlier cleanup step. Anomalously higher GC responses and subsequently very high recoveries for several pesticides inside the extracts had been obtained by a standard calibration with pesticide solution in ethyl acetate. A quicker, less efficient, environmentally safer supercritical fluid extraction (SFE) technique was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato making use of vegetable sample: anhydrous magnesium sulfate (five:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The chosen SFE situations have been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in 3 ml of ethyl acetate. Except for imidacloprid, which was not recovered below any from the assessed circumstances, pesticide recoveries were greater than 80%. A simplified approach is described by Chaput (1987) exactly where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to determine 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and 3 related metabolites in fruits and vegetables right after extraction on the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with higher chlorophyll and/or carotene content (e.g. cabbage and broccoli). Recovery information have been obtained by fortifying five distinct crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.five ppm. Recoveries averaged 93% at each fortification levels. The coefficient of variation of the method at each levels is
Estimation by GC-MS/LC-MS Because the mass spectrometer is capable of achieving higher levels of molecular specificity as when compared with the classic GC detectors and may be programmed to search for many hundred target ions, GC/MS will be a promising strategy for regulatory agencies to discover for monitoring pesticide residues in day-to-day food provide (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue method utilizing gas chromatography /mass spectrometry/selected ion monitoring (GC/MS/SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl and prothiophos residues in fruits and vegetables. Recoveries have been among 46 and 108% at the 0.5 mg/kg fortification level of every pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation were in between 0.7 and 19%, with an average of 7.5%. The estimated limits of detection from the pesticides inside the crops were 0.1-0.05 mg/kg, except that captan had limit of detection in the crops larger than 0.5 mg/kg. A strategy determined by solid-phase extraction using a carbograph 1 cartridge and reverse phase liquid chromatography /mass spectrometry (LC/MS) with an electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in 10 distinct varieties of fruits and vegetables .twelve carbamates added to vegetable supplies were extracted with methanol making use of a homogenizer followed by filtration , an aliquot in the homogenate equivalent to 5 g in the vegetable material was suitably diluted with water and passed via a 1 Carbograpg 1 extraction cartridge. Carbamates were eluted by passing by means of the cartridge 6 ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery on the analytes was much better than 80%, irrespective on the sort vegetable matrix to which the analytes had been added. A technique utilizing totally automated solid-phase extraction (SPE) sample cleanup and on-line liquid chromatographic evaluation with UV and fluorescence detection in tandem for determination of carbendazim and thiabendazole in different crops was reported by Hiemstra et al (1995). A total of 199 pesticides were determined by Fillion et al (1995) in fruits and vegetables using acetonitrile as extracting solvent along with a miniaturized charcoal-celite column cleanup followed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Carbamates were analyzed by liquid chromatography with post column reaction and fluorescence detection. Recovery data had been obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) employed a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric stress chemical ionization mass spectrometry (LC-APCI-MS) approach for the simultaneous analysis of dithiocarbamates and their degradation merchandise in crops. Average recoveries varied from 33 to 109%, and relative common deviation was among four and 21% with limits of quantification ranged from 0.25 to two.5 mg/kg. A multiresidue analysis for the determination on the 101 pesticides, like organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Analysis was performed inside the selected-ion monitoring mode. Samples had been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% from the pesticides wee amongst 70 and 110%; even so, the recoveries of acephate and folpet had been quite poor, i.e.,
Proposed program of work Standardisation of multiresidue analytical methods of pesticides
Analytical normal of selected pesticides belonging to diverse classes viz. OC (HCH (?,?,? and ? isomer), DDT (OP-DDT, PP-DDT, op-DDD, pp-DDE), Endosulfan (?,? and endosulfan sulfate) and dicofol);OP(Dimethoate, Malathion, Methyl parathion, Chlorpyriphos, Quinalphos, Triazophos, Phosphamidon,Dichlorvos Metasystox and Monocrotophos) and Synthetic Pyrethroids (Cypermethrin, Deltamethrin, Fenvalerate) for monitoring and decontamination studies have been collected from various sources as follows: Sl No.Name on the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA two?-HCH99.5EPA three?-HCH99.5EPA four?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel ten?-endosulfan99.0Excel 11endosulfan sulfate99.0Excel 12Dicofol96.0Bayer Organophosphorus 13Dimethoate96.5UPL 14Malathion97.3UPL 15Methyl parathion98.5Bayer 16Chlorpyriphos99.7Denocil crop protection Ltd. 17Quinalphos95.6Sandoz Ltd. 18Phosphamidon93.9Bayer 19Triazophos40.8Aventis Crop Science 20Monocrotophos77.0UPL 21Dichlorvos- 22Metasystox- Synthetit pyrethroids CCSRI Cypermethrin,99.0CCSRI Deltamethrin
Fenvalerate99.0
99.0CCSRI
4.1.1Stock common solution: Stock normal solution of various pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as working regular and to check the mindividual chromatographic peaks for their suitability for multiresidue evaluation. 4.1.2Preparation of mixed common solytion: in the individual regular solutions a mixed common resolution is usually to be ready for approach mdevelopment and decontamination studies. four.1.3Extraction and cleanup In the review of literature three strategies proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) happen to be selected to conduct the extraction and cleanup process where both the liquid-liquid along with a solid-phase extraction having a cartridge column will likely be compared to create a quick,easier and cost-effective technique to screen a wide range of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) is usually to be utilized for estimation on the pesticide residues. The operating situations will also be studied as stated within the chosen 3 techniques. 4.1.5standardisation on the mathod: The selected method wil be standardized by conducting a recovery study using the mixed regular by spiking inside the fruits and vegetables. four.2Monitoring of pesticide residues: 4.2.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling location: From two reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: Once in every single month for 1 year. Volume of sample: 1 kg of every single sample. 4.2.2pesticide residues to be monitored: Each of the pesticides listed in table two. four.3Decontamination research The pesticides are to become chosen on the basis of their greater use pattern in W.B. the sa]elected pesticides are listed as follows: OC (?-endosulfan, ?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyriphos, Quinalphos, Dimethoate, Triazophos, Malathion, Methyl parathion, phosphamidon, monocrotophos, metasystix; Synthetic pyrethroids: Cypermethrin, Deltamethrin and Fenvalerate. four.3.1Decontamination processes to become followed: 4.three.1.1Washing with water: Chopped samples will likely be taken in a tray containing water and the material will be gently rubbed with water for about one minute along with the water will likely be decanted or it's rinsed below operating tap water for 130 sec., with gentle rotation by hand . washing is usually to be repeated twice or thrice. 4.3.1.2Salt water washing: Chopped samples is going to be dipped within a beaker containing 2% or 55 sodium chloride answer. After 10-15 minutes the plant samplws will probably be gently rubbed by hand in salt answer and salt water is going to be decanted. Then the samples will likely be washed in water. 4.3.1.3 Boiling/Cooking: Unwashed samples wil be chopped and boiled inside a beaker till the water is totally evaporated covering the containr with or without having lid. Samples is usually to be permitted to cool. four.three.1.4 Mixture in the above strategies like soak in water for 15 min., rinse with water, cut into pieces and boiled in water 4.three.1.5Wash with soap resolution, rinse with water.
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