Pesticides In Cereals Research Articles

Development and validation of a method for the analysis of trifludimoxazin, picarbutrazox and pyraziflumid residues in cereals, vegetables and fruits using ultra-performance liquid chromatography/tandem mass spectrometry

A sensitive method for the determination of three new pesticides (trifludimoxazin, pyraziflumid and picarbutrazox) in cereals, vegetables and fruits samples has been developed using ultra-performance liquid chromatography/tandem mass spectrometry. The analytes were extracted using acetonitrile containing 1% formic acid, and then the extracts were purified using primary secondary amine and octadecylsilane. The compounds were eluted in < 3.5 min using an electrospray ionization source in positive mode. Good linearities (R2 > 0.9916) were acquired for the analytes in all matrices. The limit of detection and quantification were 0.05–5 μg kg−1 and 10 μg kg−1 for all the three target compounds, respectively. The recoveries were 74.4–105.1% and the relative standard deviations values were lower than 12.4% at three spiked levels (10, 100 and 500 μg kg−1). The results indicated that the method is reliable for monitoring the three pesticides in cereals, vegetables and fruits.

Development, validation, and application of a multi-method for the determination of mycotoxins, plant growth regulators, tropane alkaloids, and pesticides in cereals by two-dimensional liquid chromatography\xa0tandem mass spectrometry

Mycotoxins and pesticides regularly co-occur in agricultural products worldwide. Thus, humans can be exposed to both toxic contaminants and pesticides simultaneously, and multi-methods assessing the occurrence of various food contaminants and residues in a single method are necessary. A two-dimensional high performance liquid chromatography tandem mass spectrometry method for the analysis of 40 (modified) mycotoxins, two plant growth regulators, two tropane alkaloids, and 334 pesticides in cereals was developed. After an acetonitrile/water/formic acid (79:20:1, v/v/v) multi-analyte extraction procedure, extracts were injected into the two-dimensional setup, and an online clean-up was performed. The method was validated according to Commission Decision (EC) no. 657/2002 and document N° SANTE/12682/2019. Good linearity (R2 > 0.96), recovery data between 70-120%, repeatability and reproducibility values < 20%, and expanded measurement uncertainties < 50% were obtained for a wide range of analytes, including very polar substances like deoxynivalenol-3-glucoside and methamidophos. However, results for fumonisins, zearalenone-14,16-disulfate, acid-labile pesticides, and carbamates were unsatisfying. Limits of quantification meeting maximum (residue) limits were achieved for most analytes. Matrix effects varied highly (−85 to +1574%) and were mainly observed for analytes eluting in the first dimension and early-eluting analytes in the second dimension. The application of the method demonstrated the co-occurrence of different types of cereals with 28 toxins and pesticides. Overall, 86% of the samples showed positive findings with at least one mycotoxin, plant growth regulator, or pesticide.Graphical abstract

Development of QuEChERS extraction method for the determination of pesticide residues in cereals using DART-ToF-MS and GC-MS techniques. Correlation and quantification study

Cereal crops comprise more than 60 % of agricultural production worldwide. To ensure high production, the extensive use of pesticides is common practice. Analysis of pesticide residues in food and particularly cereals has become an essential requirement for consumers, producers, food inspectors and authorities. However, the determination of pesticides in cereal samples is not an easy task due to the complexity of the matrices and the trace levels of pesticides. In this study, a simple and high-throughput method was validated for the determination of multi-residue pesticide in 30 different types of cereals which are commonly consumed around the world. QuEChERS procedure has been developed, a mixture of primary-secondary amine and C18 proved better performance for the reduction of the interfering substances from the cereal grains than multiwalled carbon nanotubes. For a comprehensive investigation, the pesticide cereals contents were purified following the established cleanup method and detected by DART-ToF-MS and GC-MS. As “soft” and “hard” MS ionization methods, DART-ToF-MS and GC-MS are strong nominated for comprehensive studies of the unknown molecules. The results showed that 19 pesticides were successfully identified by both techniques in all samples, 16 by DART-ToF-MS and 13 using GC-MS. Regarding the correlation between the developed methods, 10 pesticides were detected as a commonality between the two techniques, this indicates that a single MS technique is not sufficient to detect all of the existing pesticides in cereals. The findings exposed that the two MS techniques are complementary, and both can be used for comprehensive identification of the pesticides presented in cereals. Quantitative analysis was performed using GC-MS under the selective ion monitoring mode by external and internal standard methods. Tributyl phosphate has been used as an internal standard. The measured limits of detection ranged between 4 and 9 μg kg−1 for all pesticides, while the limit of quantification values was <34.8 μg kg−1, which were below the regulatory maximum residue limits. The coefficient of determination was >0.9980 within the calibration linearity range of 15–6250 μg kg−1 for the detected pesticides. The recovery of all detected pesticides was in the range 75.28–122.02 % (n = 3) with associated RSDs <14 % indicating satisfactory accuracy.

超臨界流体抽出およびLC-MS/MS による穀類中の残留農薬の一斉分析法の妥当性評価

超臨界流体抽出およびLC-MS/MS による穀類中の残留農薬の一斉分析法の妥当性評価

Dynamic Microwave-assisted Extraction Online Coupled with QuEChERS for the Determination of Organophosphorus Pesticides in Cereals by Gas Chromatography

A rapid analytical method was first developed to detect organophosphorus pesticides(OPPs) in cereals, which used dynamic microwave assisted extraction(DMAE) coupled online with a modified quick, easy, cheap, effective, rugged, and safe(QuEChERS) method. Cereals samples were mixed with a certain amount of quartz, C18 and primary second amine(PSA), and extracted successively with the acetonitrile-water solution(80%, V/V) under microwave irradiation. The obtained eluate was directly introduced into a collection tube containing NaCl and MgSO4. Finally, the supernate was evaporated and reconstructed, and determined by gas chromatographic spectrometry. Some factors affecting the experimental results were studied and optimized. The extraction and purification processes were carried out coinstantaneously and 12 samples could be treated in one step in 4 min. Low limits of detection(0.43–1.31 µg/kg) for OPPs were obtained in cereals. The relative standard deviations(RSDs) were 2.1%–9.3%. The recoveries of OPPs ranged from 76.1% to 100.2%. By combining the advantages of DMAE with QuEChERS, the sample pretreatment process was simple to operate, with little amount of organic solvent. The whole extraction process was completed in a closed environment, therefore it was very appropriate for daily analysis of OPPs in cereals.

Simultaneous determination of pesticides, mycotoxins, and metabolites as well as other contaminants in cereals by LC-LC-MS/MS

A 2D LC-MS/MS method for the simultaneous determination of 350 pesticides, 16 mycotoxins as well as the growth regulators Chlormequat and Mepiquat was developed. The method is applicable to cereals and products thereof. Attention should be paid to the simultaneous analysis of the cereal-relevant mycotoxins aflatoxin B1, B2, G1 and G2, ochratoxin A, deoxynivalenol and zearalenone. Moreover, the tropane alkaloids atropine/scopolamine could be integrated into the final method. The samples were extracted with a mixture of acetonitrile/water (80:20), diluted with acetonitrile and injected into an LC-LC-MS/MS system. There were no further manual clean-up steps. The automatic online clean-up took place during the HILIC-separation in the first dimension (YMC-Pack Diol; 2.1 × 100 mm; 5 μm, 120 Å). Here, polar matrix compounds were retained, while the majority of the analyte scope eluted in a fraction at the beginning of the analytical run. This fraction was transferred to the second dimension by a packed loop interface (Agilent Zorbax SB-C8; 4.6 × 12.5 mm; 5 μm; 80 Å). On the second column (Phenomenex Synergi Fusion RP C18; 2 × 100 mm; 2.5 μm; 100 Å), the majority of the scope was separated by a typical RP-gradient. Only some of the polar pesticides could not be transferred to the second column. They eluted directly after the transfer step from the HILIC-column to the MS/MS. The final method was sensitive enough to meet all the regulated maximum levels for pesticides in cereals according to EU Regulation 396/2005 and those for contaminants according to EU Regulation 1881/2006. Above all, the method was so robust and accurate that nearly 90% of the pesticides and all the tested mycotoxins, growth regulators and tropane alkaloids fulfilled the validation criteria of the SANTE guideline document, although the demanding criteria are only applicable to pesticides. For the verification, eight proficiency tests were passed successfully: three for the pesticide analysis, three for the mycotoxin analysis, and two for the analysis of the tropane alkaloids. In addition to the already mentioned contaminants, the six most important ergot alkaloids (e.g. ergotamine/ergotaminine) and two modified mycotoxins (deoxynivalenol-3-glucoside and zearalenone-sulfate, also known as masked mycotoxins) were detected during the routine analysis of rye and corn samples.

Effects of milling on the extraction efficiency of incurred pesticides in cereals

ABSTRACTThis study investigated the effects of particle size and milling temperature on the extraction efficiencies of pesticide residues from cereal flour. Samples of cereal grains (barley, oat, rye and wheat) were milled using a centrifugal mill with four different sieves (0.2, 1.0, 3.0 and 5.0 mm) or a knife mill both at room temperature and after freezing of the grain at –80°C overnight. The incurred pesticides in the test materials were extracted by the QuEChERS method and analysed by LC-MS/MS and GC-MS/MS. The particle size distribution for the milled samples was determined using a vibratory sieve shaker. Based on the pesticide levels recovered from each of the different millings and the corresponding particle size distributions, it was confirmed that smaller average particle sizes increase the extraction efficiency up to 31%, with all other factors equal. The cereals milled at room temperature produced lower pesticide extraction efficiencies compared with cereals milled when still frozen, especially for heat-sensitive pesticides. Furthermore, milling frozen grains was easier and resulted in more homogeneous samples with smaller relative particle sizes.

Trace analysis of some organophosphorus pesticides in rice samples using ultrasound-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography.

An ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of a floating organic drop method followed by high-performance liquid chromatography was developed for the extraction, preconcentration, and determination of trace amounts of organophosphorus pesticides in rice samples. Variables affecting the performance of both steps were thoroughly investigated. Some effective parameters on extraction were studied and optimized. Under the optimum conditions, recoveries for rice sample are in the range of 58.0-66.0%. The calibration graphs are linear in the range of 4-800 μg/kg and, limits of detection and limits of quantification are in the range of 1.5-3 and 4.2-8.5 μg/kg, respectively. The relative standard deviation for 50.0 μg/kg of organophosphorus pesticides in rice sample are in the range of 4.4-5.1% (n = 5). The obtained results show that proposed method is a fast and simple method for the determination of pesticides in cereals.

Multiresidue analysis of over 200 pesticides in cereals using a QuEChERS and gas chromatography–tandem mass spectrometry-based method

A simple and high-throughput multiresidue pesticide analysis method was developed and validated for 219 pesticides in cereals (corn, wheat flour and rice) based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS). Different buffer system (acetate- and citrate-buffered) and sample to solvent ratios (sample amount) were compared in the modified QuEChERS procedure to get better recovery and clean-up results. The limits of quantification (LOQ) ranged between 5 and 50μgkg−1, and for the majority of the pesticides the LOQ were 5μgkg−1, which were below the regulatory maximum residue limits. The coefficient of determination (r2) was >0.99 within the calibration linearity range of 2–200μgkg−1 for the majority of the pesticides. Most recoveries at 5, 10, 20, 50, 100 and 200μgkg−1 were in the range 70–120% (n=6) with associated RSDs<20% indicating satisfactory accuracy.

Medium-assisted non-polar solvent dynamic microwave extraction for determination of organophosphorus pesticides in cereals using gas chromatography-mass spectrometry

A fast and green pretreatment method, medium-assisted non-polar solvent dynamic microwave extraction, was first applied to extract ten of organophosphorus pesticides (OPPs) from five cereal samples. Without adding any polar solvent, graphite powders (GP) were used as microwave absorption medium to transform microwave energy into heat energy. For recycling GP, an extractor was made by sealing GP inside the exterior tube of a glass sleeve. By dynamic microwave extraction using hexane as extraction solvent, ten OPPs could be extracted completely within 200s, and the extract was directly analysed by GC–MS without any clean-up process. The effects of some experimental parameters on extraction efficiency were investigated and optimised. Relative standard deviations of intra- and inter-day ranging from 1.02% to 5.32% were obtained. Five real samples were analysed, and the recoveries obtained were in the range of 73.2–99.8%, and the relative standard deviations were lower than 6.63%.

Improvement and extension to new analytes of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography–tandem quadrupole mass spectrometry revisited

This article describes a substantially improved multi-residue method for the determination of a large number of pesticides in cereal samples (wheat, rye, barley, oats, maze, buckwheat etc.) and various animal feeds. The sample preparation method and the GC–MS/MS acquisition method were modified to accommodate new complex cereal and feed matrices and to extend the existing analytical scope to 167 pesticides. The co-extractives were reduced by the joint use of primary secondary amine (PSA) and octadecyl (C18), 75mg and 50mg/1mL of acetonitrile extract, in the presence of MgSO4, and thus the optimal recovery and analytical selectivity were obtained simultaneously. The new cleanup procedure was faster and easier to handle than our previously applied cleanup procedure. The overall recoveries of the pesticides from buckwheat and rye at the three spiking levels of 0.01, 0.05 and 0.25mgkg−1 were 96±9% with relative standard deviations of 10±4% on average. At the lowest spiking level of 0.01mgkg−1, 137 of 167 pesticide residues (82%) fulfilled the validation criteria with recoveries in the range of 70–120% and RSDs less or equal 20% whereas in the previous approach it was 93 out of 140 analytes (66%). The developed method was implemented in a routine analysis of approximately 900 real samples, providing an increased scope of the analysis, improved analytical performance parameters and improved ruggedness versus the previous approach. A total of 17% analyzed samples contained pesticide residues. There were 24 different compounds encountered in the samples, of which pirimiphos-methyl, tebuconazole, deltamethrin, and chlorpyrifos-methyl were the most frequent ones.

Preliminary Studies on the Determination Bb Modern Methods (GS, GS/MS) of Organochlorine Pesticides in Cereals

Pesticides reach the grain directly as a result of phytosanitary treatments applied and indirectly through acquisition of water and soil. Time to disappearance of half the quantity of soil is: 1-4 years aldin, 1-7 years dieldrin, 2-10 years DDT. In areas where, the use of organochlorine pesticides was abandoned long ago than in our country, the contamination of these products is steadily decreasing but continuous monitoring. Separation and identification of compounds present in a sample using GC / MS is more powerful than if the same sample would be analyzed only by GC content or by MS. If the sample is analyzed by gas chromatography may arise some confusion, because there is a possibility that two molecules have the same retention time. Similarly, if the MS analysis is performed it is possible that two molecules have similar mass spectra. When, however, combines gas chromatography with mass spectrometry is highly unlikely that two different molecules behave similarly in the gas chromatograph and mass spectrometer. In this way the identification of pesticide residues in various matrices is not only based on retention times but also on mass spectra, thus eliminating the possible confusion that could arise if the identification were done using only one of the methods mentioned (compounds that have the same retention time or molecules with similar mass spectra).

Evaluation of a multiresidue method for pesticides in cereals using supercritical fluid extraction and gas chromatographic detection

Supercritical fluid extraction (SFE) was evaluated to be applied for residue analysis of 22 gas chromatography/electron capture detector-nitrogen phosphorus detector (GC/ECD-NPD) amenable pesticides in rice, wild rice and wheat. Samples were extracted with supercritical carbon dioxide at 200 atm pressure and 50°C temperature, using methanol as a static modifier. Mean recoveries obtained with the proposed SFE method at two spiking levels with four replicates per level are compared with those obtained with an ethyl acetate-based solvent extraction/gel permeation chromatography (GPC) clean up method. Both methods gave consistent high recoveries for almost all the pesticides from all the commodities with overall mean recoveries higher than 70% with relative standard deviations lower than 20%. Remarkable exceptions were captafol and dimethoate, for which low and/or non-reproducible recoveries were obtained with the SFE method. Residue levels determined with both methods in nine different incurred samples of wheat, containing some of the studied pesticides, were very similar, but, in all cases, slightly higher levels were determined with the SFE method.

Development of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography–tandem quadrupole mass spectrometry: II. Improvement and extension to new analytes

This paper describes the extension and re-validation of a previously published multi-residue method to currently 140 pesticides and 4 pesticide degradation products in cereals and feedingstuffs. The pesticides were extracted using buffered QuEChERS (“quick, easy, cheap, rugged, effective and safe”) method and then cleaned up using dispersive solid-phase extraction with Bondesil PSA and C18 sorbents, and optionally by a freezing-out clean-up step. The final extracts were analyzed in a single injection gas chromatographic-tandem quadrupole mass spectrometric (GC–MS/MS) acquisition method. A high degree of confidence was achieved by entering two multiple reaction monitoring transitions per compound. In this way, quantification of analytical results and unequivocal identification of pesticide residues in compliance with the recent European Union criteria could be done in a single analysis. Thorough optimization of the GC–MS/MS acquisition conditions and application of an effective clean-up procedure has resulted in a remarkable enhancement of the validation parameters. The linearity of the calibration curves was excellent in matrix-matched standards, and yielded the coefficients of determination ( R 2) ≥ 0.99 for approximately 96% of the target analytes. Average recoveries of the pesticides spiked at 0.01 mg kg −1 into a feed mixture and wheat grain were in the range 70–120% with associated RSD values ≤20% for approximately 60% and 67% of the compounds, respectively. At the higher spiking levels of 0.05, 0.1 and 0.5 mg kg −1 average recoveries and RSDs readily met the validation criteria for nearly all the studied pesticides. Based on these results, the proposed approach has been proven to be highly efficient and suitable for routine determinations of multi-class pesticides in a range of cereal and related matrices. Up to now, 145 samples of matrices of differing complexity including cereals grain, bran, whole ears, straw, hay, feed mixtures and other samples such as malt, starch and dry vegetables have been analyzed. A total of 15 different pesticides have been detected, among which pirimiphos methyl (19 cases), deltamethrin (14 cases), tolylfluanid (5 cases), dichlofluanid (5 cases), and tebuconazole (4 cases) were the most frequently encountered ones.

Development of a multi-residue screening method for the determination of pesticides in cereals and dry animal feed using gas chromatography–triple quadrupole tandem mass spectrometry

A multi-residue screening method for simultaneous analysis of 122 gas chromatography amenable pesticides in dry matrices such as cereal grain and certain feedingstuffs was developed. The method entails a simple extraction of re-hydrated sample with acetonitrile followed by a dispersive solid phase extraction (dispersive-SPE) clean-up step prior to the final determination by gas chromatography/triple quadrupole tandem mass spectrometry (GC–MS/MS). Due to complexity of analyzed matrices, two MS/MS transitions were set for each pesticide to eliminate the need for re-analysis of potentially positive samples, and provide unequivocal identification of detected pesticides in accordance with recent guidelines, in a single analytical run. Thus, in the developed GC–MS/MS acquisition method, a total of 216 different multiple reactions monitoring (MRM) transitions were monitored in one set of experimental conditions. To evaluate performance of the method, validation experiments were carried out on wheat grain at three spiking levels (0.01, 0.02 and 0.05 mg kg −1). Additional recovery tests at 0.05 mg kg −1 were carried out on several other matrices. The recoveries ranged between 73 and 129% with associated relative standard deviations between 1 and 29% for the majority of pesticides. Limits of detection were less or equal to 0.01 mg kg −1 for approximately 68% of pesticides. The applicability of the proposed method to detect and quantify pesticide residues has been demonstrated in the analysis of 136 real samples. Additionally, the method was favorably compared with an acetone extraction method (accepted as a reference method by some of European and U.S. authorities) in the analysis of real samples known to contain pesticide residues.

Determination of endocrine-disrupting compounds in cereals by pressurized liquid extraction and liquid chromatography–mass spectrometry: Study of background contamination

A sensitive method based on pressurized liquid extraction (PLE) and liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS) has been developed for the determination in cereal samples of seven endocrine-disrupting compounds: bisphenol A (BPA), 4- tert-butylbenzoic acid (BBA), 4-nonylphenol (NP), 4- tert-butylphenol ( t-BP), 2,4-dichlorophenol (DCP), 2,4,5-trichlorophenol (TCP) and pentachlorophenol (PCP). For the PLE procedure, methanol was selected as the extraction solvent. An experimental design approach was applied to optimize other PLE parameters. The recoveries achieved for the all seven compounds were in the 81–104% range, with relative standard deviations of 4–9%. An additional preconcentration step, based on solid-phase extraction (SPE), after the PLE step proved to be a successful way for obtaining a more sensitive method. The detection limits achieved in corn breakfast cereals were in the 0.003–0.013 μg g −1 range, except for BPA, with a detection limit of 0.043 μg g −1, for a sample size of 2.5 g. These values are similar to or even lower than currently legislated limits for pesticides in cereals and cereal-based foodstuffs. We also investigated possible contamination during the experimental process by the target compounds released from purified water, plastics, syringes, peristaltic pump tubes, glassware and other laboratory materials in contact with the samples along the analytical process.

High Throughput Analysis of N‐Methyl Carbamate Pesticides in Cereals and Beans by Dual Countercurrent Chromatography and Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry

We developed a new analytical method for analysis of N‐methyl carbamate pesticides in cereals and beans using dual counter‐current chromatography (dual CCC) and liquid chromatography‐electrospray ionization tandem mass spectrometry (ESI LC/MS/MS). After pesticides were extracted from cereals and beans with ethyl acetate, each extract was cleaned up by dual CCC using a non‐aqueous binary solvent system composed of n‐hexane‐acetonitrile and analyzed by ESI LC/MS/MS with a short column. The average recoveries from cereals and beans fortified at the level of 0.01 ppm ranged from 73.9 to 119.6%, with the coefficients of variation from 0.7 to 6.8%. At the fortified level of 0.5 ppm, the recoveries ranged from 72.1 to 117.1% with coefficients of variation from 0.4 to 9.3%. The present analytical method of N‐methyl carbamate pesticides in cereals and beans is considered to be useful for monitoring the pesticide residues in cereals and beans.

Determination of Nine Organophosphorus Pesticides in Cereals and Kidney Beans by Capillary Gas Chromatography with Flame Photometric Detection

A method is developed for the determination of nine organophosphorus pesticide residues in cereals and kidney beans by capillary gas chromatography with flame-photometric detection. In this method, dichloromethane is used for clean-up after liquid-liquid extraction. It is shown that good separations are obtained using a fused-silica capillary column (DB-1701) by the optimized temperature program. In the spiked levels of 0.012-0.43 mg/kg, the recoveries are from 83.7% to 107%, with the relative standard deviation between 3.2% and 13% and limits of detection from 8.2 to 15 microg/kg. The method is rapid, sensitive, and practical.

Ground deposit of pesticides in relation to the cereal canopy density

Pesticides not reaching the intended target may have negative effects on the environment and the field ecosystem. To estimate the potential ground water pollution and risk for soil-dwelling organisms it is necessary to estimate the amount of pesticide reaching the soil in different spraying situations. Literature shows that ground deposition may vary even within equal growth stages due to variations in canopy density. This paper discusses the feasibility of estimating the ground deposition of pesticides from canopy density in cereal fields. Spray experiments were carried out in wheat and barley with flat-fan nozzles of two sizes. Differences of ground deposition between the two nozzle sizes were insignificant. Adding surfactant to the spray solution significantly reduced the soil deposition in barley and in wheat cv Sleipner but not in cv Haven. A significant effect of Leaf Area Index (LAI) on ground deposition was obtained. A simple exponential model based on the LAI with an extinction coefficient of 0.48–0.50 may for many occasions satisfactorily describe the soil deposition of pesticides in cereals. Using non-destructive LAI-measurements combined with the deposition model may be useful in pesticide risk assessment on field, farm and larger regional scale and is optimising the application rate in site-specific farming. © 1999 Society of Chemical Industry

Ground deposit of pesticides in relation to the cereal canopy density

Pesticides not reaching the intended target may have negative effects on the environment and the field ecosystem. To estimate the potential ground water pollution and risk for soil-dwelling organisms it is necessary to estimate the amount of pesticide reaching the soil in different spraying situations. Literature shows that ground deposition may vary even within equal growth stages due to variations in canopy density. This paper discusses the feasibility of estimating the ground deposition of pesticides from canopy density in cereal fields. Spray experiments were carried out in wheat and barley with flat-fan nozzles of two sizes. Differences of ground deposition between the two nozzle sizes were insignificant. Adding surfactant to the spray solution significantly reduced the soil deposition in barley and in wheat cv Sleipner but not in cv Haven. A significant effect of Leaf Area Index (LAI) on ground deposition was obtained. A simple exponential model based on the LAI with an extinction coefficient of 0.48–0.50 may for many occasions satisfactorily describe the soil deposition of pesticides in cereals. Using non-destructive LAI-measurements combined with the deposition model may be useful in pesticide risk assessment on field, farm and larger regional scale and is optimising the application rate in site-specific farming. © 1999 Society of Chemical Industry