Pesticides In Agricultural Products Research Articles

Lambda‐Cyhalothrin Nanosuspension Prepared by the Melt Emulsification‐High Pressure Homogenization Method

The nanosuspension of 5% lambda‐cyhalothrin with 0.2% surfactants was prepared by the melt emulsification‐high pressure homogenization method. The surfactants composition, content, and homogenization process were optimized. The anionic surfactant (1‐dodecanesulfonic acid sodium salt) and polymeric surfactant (maleic rosin‐polyoxypropylene‐polyoxyethylene ether sulfonate) screened from 12 types of commercially common‐used surfactants were used to prepare lambda‐cyhalothrin nanosuspension with high dispersity and stability. The mean particle size and polydispersity index of the nanosuspension were 16.01 ± 0.11 nm and 0.266 ± 0.002, respectively. The high zeta potential value of −41.7 ± 1.3 mV and stable crystalline state of the nanoparticles indicated the excellent physical and chemical stability. The method could be widely used for preparing nanosuspension of various pesticides with melting points below boiling point of water. This formulation may avoid the use of organic solvents and reduce surfactants and is perspective for improving bioavailability and reducing residual pollution of pesticide in agricultural products and environment.

An Intelligent Robot System for Spraying Pesticides

In order to reduce pesticides in agricultural production caused by direct contact with the human body injury, and improve the efficiency of agricultural spraying operations, this paper proposes the design of intelligent WiFi wireless controlled spraying pesticides robots. For monitoring the microcontroller core, a wireless router for the network connection point is employed. The camera captures video, Android phones and smart monitoring system operation. Test results show that the design realizes spraying pesticides by robot to replace staff job, and achieves good results.

Personal safety issues related to the use of pesticides in agricultural production in the Al-Batinah region of Northern Oman

The level of uptake and use of personal protective equipment (PPE) by farm workers in Oman is low; the conditions under which pesticides are stored are frequently below acceptable international standards. Research was undertaken to explore the drivers working against safe storage of agrochemicals and effective personal protection usage by pesticide application personnel. Results from a survey of over 200 respondents, representing workers in, and owners of, farms either within or outside a local farmer's association (FA), suggest that FA membership raises standards of behaviour both in terms of safe pesticide storage and use of PPE. Age of respondents had no apparent effect on the likelihood of PPE (gloves and masks) use. PPE use was, however, highest among respondents with more advanced educational backgrounds. Positive responses for glove and mask use, when applying pesticides, were higher for owners and workers in FA farms compared to non-FA farms. Lowest reported use of PPE was among workers in non-FA farms. Analysis of responses appears to indicate that behaviour patterns of workers in FA farms mirror that of the farm owners. This was not the case in non-FA farms. The results suggest that conformity to social norms, in this case acceptable work-environment behaviour, is a powerful driver behind raised usage levels of PPE in farms in Oman.

Quantitative Determination of Butocarboxim in Agricultural Products Based on Biotinylated Monoclonal Antibody

The carbamate pesticides, such as butocarboxim, are considered hazardous substances because of their toxicity to non-target species and their persistence in the environment and agricultural products. Thus, it is highly desirable to design a sensitive and rapid detection of butocarboxim for the safety of agriculture products. In this study, a new hapten of butocarboxim was designed and synthesized; a highly affinitive and selective monoclonal antibody (mAb) against butocarboxim was produced, which was obtained from immunized BALB/c female mice. Based on the biotinylated mAb, an indirect competitive enzyme-linked immunosorbent assay (bi-ELISA) and an indirect competitive electrochemical immunoassay (bi-ECIA) for detecting butocarboxim pesticides in agricultural products were developed. Under optimized experiment conditions, biotin with an amount of 20-fold molar excess against mAb was used, and meanwhile, for bi-ECIA, the concentration of coating antigen is two times lower than that of bi-ELISA (0.031 and 0.062 μg mL−1, respectively), the concentration of mAb is four times lower than that of bi-ELISA (0.07 and 0.28 μg · mL−1, respectively). Depending on the assay format, the limits of detection (LOD) of bi-ECIA and bi-ELISA were 1.41 and 7.55 ng mL−1, respectively. The results showed that the sensitivity (LOD) of bi-ECIA was over five times higher than that of bi-ELISA. At the same time, the recoveries obtained by standard butocarboxim addition to apple and greengrocery samples were from 89.6 to 108.5 % for bi-ELISA and from 87.2 to 109.8 % for bi-ECIA.

A preliminary study of the content and distribution of pesticide residues in soil samples from the Kathmandu valley, Nepal .

The increasing use of pesticides for agricultural production is causing soil pollution problems in different parts of Nepal. Uncontaminated agricultural soils are of great importance as they have a direct impact on food security and human health. The objective of this study was to investigate the quality and quantity of pesticides in soil samples from districts near the capital city of Kathmandu, from where fruit and vegetables are brought to the city for consumption. A questionnaire survey was carried out in four districts around Kathmandu city to investigate the types of pesticides that are most commonly used in these districts. A total of 15 soil samples were taken at a depth of 10 cm and four complete soil profiles were sampled at three different depths (10 cm, 30 cm and 50 cm) on the farms of those who were interviewed. A total of four replicates of each soil sample were extracted and analyzed. The pH, soil texture and organic carbon content of the soil samples were analyzed to understand the general soil characteristics. The QuEChERS method used for the analysis of food samples was modified and applied to the soil samples. An HPLC-MS/MS was used for the qualification and quantification of the pesticide residues in the soil samples. The questionnaire survey revealed that carbendazim, chlorpyrifos-methyl, parathion-methyl, imidacloprid, metalaxyl, dimethoate, omethoate and dichlorvos were the most commonly used pesticides in the area studied. The chemical analysis showed that soil samples from all the districts except Kathmandu city were contaminated with various pesticides. The soil samples collected at the depth of 10 cm were found to be contaminated with the fungicide carbendazim and the insecticide chlorpyrifos-methyl at rates of up to 0.038 mg kg<sup>-1</sup> and the systemic insecticide imidacloprid was found at up to 0.016 mg kg<sup>-1</sup>. The study of soil samples taken at different depths (10 cm, 30 cm and 50 cm) showed that pesticides were homogenously distributed with soil depth. The recovery between 77.5-112%, linearity between 0.01 mg kg<sup>-l</sup> - 2 mg kg<sup>-l</sup> with correlation factors R2 higher than 0.99 and LOQ between 0.2 µg kg<sup>-1</sup>- 6.25 µg kg<sup>-l</sup> were found. Some samples were contaminated with parathion-methyl, a highly carcinogenic organophosphorous insecticide, even though these pesticides had already been banned. For the first time, this study provides information about soil contamination levels due to pesticides in Central Nepal and shows that further research and information campaigns for farmers are necessary.

Validation study on a multi-residue method for determination of pesticides in agricultural products by LC-MS/MS

A multi-residue method for 122 pesticides in agricultural products was validated in accordance with Japanese guidelines for residual agricultural chemicals in food. The sample was extracted with acetonitrile. Co-extractives were removed by GPC-graphitized carbon column SPE, followed by silica gel/PSA cartridge column SPE. The pesticides in the test solution were determined by LC-MS/MS using scheduled MRM in combination with polarity switching. Validation tests were performed on spinach, brown rice, soybean, orange and tomato fortified at 0.01 and 0.1 μg/g. The pesticides at each level were analyzed in two samples per day on five different days. In conclusion, among 122 pesticides tested for each level, 121 pesticides (but not disulfoton) were found to meet all of the guideline criteria.

Validation study on a multi-residue analysis of pesticides in agricultural products by using phosphoric acid treatment and GC-MS/MS

A rapid method for multi-residue determination of pesticides in agricultural products was validated. The sample was cut into pieces and placed into a mixer cup containing half weight amount of 10% phosphoric acid in order to suppress degradation of easily degraded pesticides, represented by captan, and then homogenized. Pesticides in the phosphoric acid-treated sample were extracted with acetonitrile using a homogenizer, followed by salting out with anhydrous magnesium sulfate and sodium chloride. The extract was cleaned up on a C18 and graphite carbon black/PSA mini-cartridge column. Some pesticides gave tailing peaks, but these peaks became sharp and symmetrical when polyethylene glycol (PEG) 300 was added to the test solution. Recovery tests were performed on nine kinds of agricultural products (brown rice, soybean, spinach, cabbage, potato, orange, apple, strawberry, and Japanese pear) fortified with 170 pesticides at 0.01 and 0.1 μg/g. Each concentration of pesticide residue was extracted from 2 samples on 5 separate days. The trueness of the method for 147-164 pesticides in each sample was 70-120% with satisfactory repeatability and within-run reproducibility. This method is expected to useful for multi-residue analysis of pesticides in agricultural products.

Studies on rapid multi-residue analysis of pesticides in agricultural products by LC-MS/MS

Rapid multi-residue analysis of pesticides in agricultural products was studied by using LC-MS/MS. Pesticide residues in 10 g of homogenized agricultural products were extracted with 30 mL of acetonitrile and salted out with 4 g of anhydrous magnesium sulfate and 1 g of sodium chloride in the presence of citrate salts for buffering in a disposable tube. Co-extractives were removed by use of our original triple layered column (C18/GC/PSA; 60/30/60 mg). According to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan, we conducted recovery tests in 5 kinds of agricultural products (brown rice, kiwi, cabbage, sweet potato and spinach) spiked with 60 pesticides at the level of 0.01 or 0.1 μg/g. Each concentration of pesticide spiked was extracted from 2 samples per day on 5 days. Pesticides in the test solution were determined by two types of LC-MS/MS using scheduled MRM. Using this method, 58 out of 60 pesticides satisfied the guideline criteria in brown rice, 59 in kiwi, 55 in cabbage, 55 in sweet potato and 56 in spinach. This method is applicable for routine examination of pesticide residues in agricultural products.

Determination of the trace residues of four organochlorine pesticides in agricultural products by high performance liquid chromatography with modified multi-walled carbon nanotubes as solid phase extraction adsorbent

A novel method for the simultaneous determination of the trace residues of four organochlorine pesticides such as p,p'-DDD, p,p'-DDT, o,p'-DDT and p,p'-DDE in agricultural products by multi-walled carbon nanotubes (MWNTs) modified by acid oxidation on the surface as solid phase extraction (SPE) adsorbent coupled with high performance liquid chromatography (HPLC) was developed. The effects of the surface acid oxidation, SPE operations and HPLC conditions on the determination of the four pesticide residues were investigated. Under the optimized experimental conditions, the novel method provided wide linear ranges for the pesticides with correlation coefficients of 0. 997 8 - 0. 999 5, the detection limit was 0.050 mg/L for each pesticides. The recoveries from the samples spiked with the pesticide standards at three concentration levels of 0.10, 2.0 and 50 mg/L were in the range of 78% - 104% with the relative standard deviations (RSDs) of 2.7% -7.6%. This study indicated the MWNTs SPE was an efficient clean-up method to agricultural products (included dried orange peel, ginseng, cabbage and tea). The proposed method showed the advantages of accuracy and sensitivity, and can meet the requirements for the determination of low residue pesticide in agricultural products. The study provides a useful method for the analysis of trace substance of agricultural products.

Multiresidue analysis of pesticides in agricultural products by a liquid chromatography/tandem mass spectrometry based method

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of 56 residual pesticides from commercial crops. For a validation of the method, the recoveries, linearities, limits of detection (LOD), and limits of quantitation (LOQ) of the 56 pesticides were investigated. The linearities, LOD, and mean recoveries of the pesticides ranged 0.9686–0.9999, 0.00–11.54 μg/kg, and 65–82%, respectively. This method was evaluated by its application to monitor 345 agricultural products collected from 9 provinces in Korea 2011. Fifteen pesticides were detected from 39 samples and 2 or more residual pesticides were found in 7 samples. However, none of the compounds were observed above the corresponding maximum residue level. The results reflect that the detected pesticide residues were in a safe range and that residual pesticides in the agricultural products in Korea were properly controlled.

LC-MS/MS를 이용한 한국에서 유통되는 농산물의 잔류 농약 평가

본 연구에서 한국 유통 농산물 17품목(쌀, 사과, 배, 오렌지, 복숭아, 딸기, 바나나, 파인애플, 포도, 키위, 수박, 토마토, 오이, 호박, 참외, 깻잎, 상추 등)을 대상으로 다성분 분석농약 60종을 분석하기 위하여 대상농산물의 대분류별로 곡류에서는 현미, 두류는 메주콩, 과실류에서는 감귤, 채소류는 고추, 서류에서는 감자, 버섯류에서는 느타리버섯을 선정하여 회수율 실험을 수행하였다. 60% 이상의 낮은 회수율을 나타내는 성분 중 fluquinconazole, methomyl은 4가지 이상의 농산물에서 공통적으로 낮은 회수율을 나타내었다. fluquinconazole은 식품에 적용하는 식품공전 4.1.3.22의 개별 시험법을 이용한 전처리 과정을 통해 과일류, 과채류, 콩류에서 개선된 회수율 결과를 얻을 수 있을 것으로 예상되며 methomyl 은 고추, 대두, 버섯 등 식품에 적용하는 식품공전 4.1.3.15의 개별 시험법을 통해 개선된 회수율 결과를 얻을 수 있을 것으로 예상된다. 버섯, 고추에서 공통적으로 60% 미만의 낮은 회수율을 나타내었던 butocarboxim은 현재 식품공전상 개별 시험법이 존재하지 않는 항목이므로 이에 대한 개별시험법을 개발하여 다종농약다성분 시험법을 보완할 필요가 있다고 사료된다. 한국 유통 농산물 17품목(쌀, 사과, 배, 오렌지, 복숭아, 딸기, 바나나, 파인애플, 포도, 키위, 수박, 토마토, 오이, 호박, 깻잎, 상추)을 대상으로 다성분 분석농약 60종을 분석하여 농약 잔류실태를 조사하였다. 조사대상 농산물 358건 중 대부분의 농산물인 291건(81.3%)의 농산물은 농약이 검출되지 않았으며, 67건(18.7%)의 농산물에서 농약이 검출되었으나, 잔류허용기준 미만으로 검출되었다. 쌀 등 17품목에의 다소비 농산물의 농약 잔류실태를 조사한 결과 농약의 잔류량은 잔류허용기준 미만으로 ADI 대비 EDI는 0.000009%에서 0.0861%로 위해도가 아주 낮은 것으로 조사되었으며 비교적 안전한 수준으로 농산물에 대한 농약관리가 이루어지는 것으로 판단되었다. Pesticide residues in agricultural products in Korea were evaluated to create a data base to inform food policy. Pesticide residues were investigated in 17 commodities collected from 9 provinces in 2012. Our analytical method of multiresidue analysis, involved the analysis of individual recovery, linearity, limit of detection, and limit of quantitation of 60 pesticides in six matrices. The pesticides, including acetamiprid and forchlorofenuron, were evaluated in 358 agricultural samples by liquid chromatography/tandem mass spectrometry. Twenty three pesticides were detected from 67 samples. The results showed that the ratio of estimated daily intake to acceptable daily intake was 0.00009-0.0861% by the intake assessment, which means that residual pesticides in agricultural products in Korea are properly controlled.

GC-ECD와 GC-MSD를 이용한 유니코나졸 잔류실태조사

본 연구에서는 2012년 1월부터 8월까지 농산물 중 엽채류에 대하여 GC-ECD 및 GC-MSD를 이용하여 uniconazole의 잔류실태조사를 실시하였다. 겨자채에 표준용액을 0.05, 0.5 mg/kg 농도로 하여 회수율을 측정한 결과 98.9%에서 109.4%까지 양호한 결과를 나타내었다. 2012년 1월부터 8월까지 서울지역에 유통되고 있는 농산물 중 엽채류 3,632건에 대하여 모니터링을 실시한 결과 14건에서 uniconazole이 검출되었다. Uniconazole의 검출양은 0.098 mg/kg에서 2.2 mg/kg로 나타났다. 본 연구를 통하여 동시분석법으로 보다 효율적인 검사가 가능할 것으로 기대된다. We evaluated the presence of uniconazole residual pesticide in agricultural products by using multiclass pesticide multiresidue methods. Samples were collected from January to August, 2012. The pesticide was detected in 14 samples among the 3,632 samples tested. Amount of the uniconazole pesticide ranged from 0.098 to 2.2 mg/kg in the 14 samples. This method was described for the simultaneous determination of uniconazole by using gas chromatography with an electron capture detector (GC-ECD) and mass spectrometry (MS). For evaluating the GC-ECD method, uniconazole was spiked into gyeojachae at a level of 0.05, 0.5 mg/kg. The recoveries of uniconazole with the GC-ECD method ranged from 98.9-109.4%. The results indicate that our method of simultaneous analysis is applicable to uniconazole analysis.

Multi-residue Analysis of Pesticides in Agricultural Products by GC/MS Using Synchronous SIM/Scan Acquisition

Multi-residue Analysis of Pesticides in Agricultural Products by GC/MS Using Synchronous SIM/Scan Acquisition

Fungicide and insecticide activity of Justicia procumbens extracts

爵床(<i>Justicia procumbens var. procumbens L.</i>)是一种传统中药。为探明爵床提取物的抑菌杀虫活性, 采用冷浸和超声波提取相结合的方法, 分别获得了爵床甲醇、氯仿、丙酮、乙酸乙酯和正己烷等溶剂提取物; 并应用抑菌圈法研究了5种提取物对柑橘炭疽病菌(<i>Colletotrichum gloeosprioides</i>)、芦笋茎枯病菌(<i>Phomopsis asparagi</i>)、稻瘟病菌(<i>Pyricularia grisea</i>)、棉花红腐病菌(<i>Fusarium graminearum</i>)和草莓灰霉病菌(<i>Botrytis cinerea</i>)等5种植物病原真菌的抑制效果, 测定了甲醇提取物对柑橘炭疽病、芦笋茎枯病、草莓灰霉病和柑橘溃疡病(<i>Xanthomonas campestris</i>)等4种植物病菌及白蚊伊蚊(<i>Aedes albopictus</i> )、家蝇(<i>Musca domestica</i>)和菜青虫(<i>Pieris rapae</i>)等3种害虫的毒力。结果表明, 不同极性溶剂提取物8 mg?mL 1对5种植物病原真菌均有一定的抑制作用, 其中甲醇提取物对柑橘炭疽病菌、芦笋茎枯病菌、草莓灰霉病菌的抑制率均达50%以上。爵床甲醇提取物具有较强的抑菌杀虫活性, 对柑橘炭疽病菌、芦笋茎枯病菌和草莓灰霉病菌菌丝生长的抑制中浓度(EC₅₀)分别为5.94 mg?mL^-1、4.61 mg?mL^-1和5.27 mg?mL^-1, EC₉₀分别为63.69 mg?mL^-1、58.01 mg?mL^-1和54.57 mg?mL^-1; 0.25~1.00 mg?mL^-1爵床甲醇提取物对柑橘溃疡病病菌显示强抑菌作用, 0.125 mg?mL^-1显示中度抑菌作用, 最小抑制浓度(MIC)为0.062 5 mg?mL ^-1; 爵床甲醇提取物对白蚊伊蚊、家蝇和菜青虫的致死中浓度(LC₅₀)分别为0.195 8 mg?mL^-1、0.351 4 mg?mL^-1和0.287 7 mg?mL^-1, LC95分别为0.988 4 mg?mL^-1、3.053 2 mg?mL ^-1和2.584 4 mg?mL^-1。因此, 爵床提取物作为生物农药, 在农业生产中具有较好的应用前景。

Screening of Total Organophosphate Pesticides in Agricultural Products with a Cellular Biosensor

Organophosphates belong to the most important pesticides used in agricultural practice worldwide. Although their analytical determinations are quite feasible with various conventional methods, there is a lack of efficient screening methods, which will facilitate the rapid, high-throughput detection of organophosphates in different food commodities. This study presents the construction of a rapid and sensitive cellular biosensor test based on the measurement of changes of the cell membrane potential of immobilized cells, according to the working principle of the Bioelectric Recognition Assay (BERA). Two different cell types were used, derived either by animal (neuroblastoma) or plant cells (tobacco protoplasts). The sensor was applied for the detection of a mixture of two organophosphate pesticides, diazinon and chlorpyrifos in two different substrates (tomato, orange). The pesticides in the samples inhibited the activity of cell membrane-bound acetylcholinesterase (AChE), thus causing a measurable membrane depolarization in the presence of achetylcholine (Ach). Based on the observed patterns of response, we demonstrate that the sensor can be used for the qualitative and, in some concentrations, quantitative detection of organophosphates in different substrates with satisfactory reproducibility and sensitivity, with a limit of detection at least equal to the official Limit of Detection (LOQ). The assay is rapid with a total duration of 3 min at a competitive cost. The sensitivity of the biosensor can be further increased either by incorporating more AChE-bearing cells per test reaction unit or by using cells engineered with more potent AChE isoforms. Standardization of cultured cell parameters, such as age of the cells and subculture history prior to cell immobilization, combined with use of planar electrodes, can further increase the reproducibility of the novel test.

Development of an Enzyme Linked Immunosorbent Assay and an Immunochromatographic Assay for Detection of Organophosphorus Pesticides in Different Agricultural Products

ObjectiveOrganophosphorus (OP) pesticides are considered hazardous substances because of their high toxicity to nontarget species and their persistence in the environment and agricultural products. Therefore, it is important to develop a rapid, sensitive, and economical method for detecting OP pesticides and their residues in food and the environment.MethodsA broad, selective monoclonal antibody (MAb) for organophosphorus pesticides was produced. Based on the MAb, an enzyme linked immunosorbent assay (ELISA) and an immunochromatography assay (ICA) for detecting OP pesticides in different agricultural products were developed using a binding inhibition format on microtiter plates and a membrane strip, respectively.ResultsUnder the optimized conditions, the IC50 values of the ELISA ranged from 3.7 to 162.2 ng mL–1 for the 8 OP pesticides. The matrix interferences of Apple, Chinese cabbage, and greengrocery were removed by 40-fold dilution, the recoveries from spiked samples ranged from 79.1% to 118.1%. The IC50 values of ICA for the 8 OP pesticides ranged from 11.8 to 470.4 ng mL−1. The matrix interference was removed from the Chinese cabbage and Apple samples with 5-fold dilution, and the interference was removed from the greengrocery samples with 20-fold dilution. The recoveries from the spiked samples ranged between 70.6 and 131.9%. The established ELISA and ICA were specific selectivity for the 8 OP pesticides.ConclusionsThe established ELISA is a sensitive screening method for the detection of OP pesticides, but the ELISA detection method depends on a laboratory platform and requires a relative long assay time and several steps operation. The established ICA is very useful as a screening method for the quantitative, semi-quantitative or qualitative detection of OP pesticides in agricultural products, and it has advantages over ELISA methods with regard to factors such as the testing procedure, testing time, and matrix interferences, among others.

Multi-Residue Analysis of Pesticides in Agricultural Products by Liquid Chromatography Time-of-Flight Mass Spectrometry

The applicability of liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) for determining pesticide residues in agricultural products was investigated. TOF-MS conditions for monitoring target ions, together with their fragment ions, were carefully optimized. The developed LC-TOF-MS method was evaluated for 154 pesticides in soybean and spinach by using matrix-matched standards. No significant matrix effect was observed for most of the tested pesticides at a concentration level of 0.01 mg/kg, where the limits of quantification were less than 0.01 mg/kg for 145 of the 154 pesticides (S/N>10). In addition, no significant interference was observed in the chromatograms of the blank extracts. These results indicate that LC-TOF-MS determination may become a powerful tool for multi-residue analysis of pesticides in agricultural products.

Isolation and Identification of the DNA Aptamer Target to Acetamiprid

As an alternative to antibodies, aptamers have a great potential as analytical tools for pesticide detection. In this work, aptamers targeting acetamiprid were selected by a specific systematic evolution of ligands by exponential enrichment (SELEX) strategy, where a single-stranded DNA (ssDNA) library was immobilized and target modification was eliminated. After 18 rounds of repeated selection, the ssDNA pool was enriched and then 14 sequences were selected and carefully identified. At last, an acetamiprid-specific aptamer with the apparent dissociation constant (K(d)) estimated to be 4.98 μM was successfully obtained. Further work is ongoing to develop an aptamer-based detection method for field determination of this pesticides in agricultural products and environmental samples.

Effectiveness of Selected Reaction Monitoring for rapid assay of Cypermethrin Residue in Perilla Leaves

Many kinds of pesticides have been developed and used to yield a good harvest but the residues in agricul-tural products cause health problems. It is important to keep watch on these residues by using adequate methods of analysis. Pretreatment such as gel permeation chromatography (GPC) or column chromatography is often needed for the quantitative analysis of pesticide in agricultural products by conventional methods such as gas chromatography/low resolving power mass spectrometry (GC/LRMS). However, these pretreat-ments need a lot of work and take time. New methods saving the necessity of these pretreatments have been desired. We have applied selected reaction monitoring (SRM) to quantitatively determine cypermethrin residues in Perilla frutescens samples and compared the results with LRMS and HRMS in SIM mode. A background peak caused by the matrix overlapped the cypermethrin peak in the analysis using LRMS. SRM and HRMS in SIM mode provided chromatograms without matrix interference. The high selectivity of the product ion (m/z 127) produced from precursor ion (m/z 163) isolated the target peaks from the matrix peaks when using SRM. This method eliminates the pretreatment step, thus saving time and simplify ing the ana-lytical process.

Miniaturized Method Based on Matrix Solid-Phase Dispersion for the Rapid Screening of 36 Pesticides in Agricultural Food Commodities

Matrix solid-phase dispersion and gas chromatography-mass spectrometry were used for the rapid screening of 36 pesticides in agricultural products. Homogenized sample (0.5 g), C8-modified silica (0.5 g) and Na2SO4 (1 g) were mixed and transferred to a cartridge containing activated silica (0.5 g). Best recoveries (>60%) were found using dichloromethane-ethyl acetate (4:1) for elution. Analytical characteristics at spiking levels (10–100 μg/kg) were calculated for each pesticide. Matrix effects were studied by comparing the slopes of the matrix-matched calibration curves. Fruit and vegetable samples from South Africa complied with EU and South African current regulation, except for cypermethrin in green beans.