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A rapid, easy and versatile, simultaneous analytical method by LC-MS/MS based on extraction of QuEChERS method (EN 15662:2008) was developed for the determination of residual pesticides in Edamame (immature soybeans). In this method, it allowed to prepare a test solution only dilution without purification using solid column. As a result, 202 analytes met the management criteria of the guideline for validity assessment (Ministry of Health, Labour and Welfare of Japan). Thus, the present method could be useful for a rapid simultaneous determination of residual pesticides in green soybean.

A rapid, sensitive and selective analytical method by LC-MS/MS was developed and validated for the determination of cyclamate in various kinds of foods. The Preparation of test solutions was performed by heat extraction technique in accordance with an official notification method in Japan. We aimed to reduce the matrix effects in LC-MS/MS only by diluting extracts without clean-up using solid phase column. This method was assessed for 30 kinds of foods fortifying cyclamate at the concentration level of 0.5 μg/g. As a result, trueness was 85.0 to 106.6%, repeatability (RSDr) ranged from 1.7 to 9.4%, and within-laboratory reproducibility (RSDwr) ranged from was 4.1 to 9.7%. These date supported the reliability our method. Thus, this method could be useful for a rapid determination of cyclamate in various kinds of foods.

A rapid, easy and versatile, simultaneous analytical method by LC-MS/MS based on extraction of QuEChERS method (EN 15662:2008) was developed for the determination of residual pesticides in agricultural products. In this method, it allowed to prepare a test solution only dilution without purification using solid phase extraction column. The method was assessed for 210 pesticide residues in 21 kinds of vegetables and fruits at the fortification levels of 0.01 and 0.1 μg/g according to the method validation guideline (Ministry of Health, Labour and Welfare of Japan). As a result, 194 to 210 analytes met the management criteria of the guideline. Thus, the present method could be useful for a rapid simultaneous determination of residual pesticides in agricultural products.

A simple determination method of dinoseb and dinoterb in agricultural products, livestock products and seafood by LC-MS/MS was developed. Agricultural samples were extracted with acetone (in the case of rice, soybean and tea leaf, phosphoric acid was added). An aliquot of crude extract was partitioned with hexane and sat. sodium chloride solution. In the case of livestock products and seafood, samples were extracted with a mixture of acetone, hexane, water and sodium chloride, and the organic layer was collected. Clean-up was performed using a PSA mini column. The LC separation was performed on a C18 column with methanol-water (19 : 1) containing 0.005 v/v% acetic acid as a mobile phase, and MS with negative ion electrospray ionization was used for detection. The calibration curve was linear between 0.0005 to 0.04 µg/mL for each compound. Average recoveries (n=5) of dinoseb and dinoterb from 20 kinds of agricultural products, livestock products and seafood fortified at the MRLs were 77-111%, and the relative standard deviations were 2-15%. The limits of quantitation were 0.001 µg/g for both compounds.

A simple determination method of hydramethylnon in agricultural products by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The sample was homogenized with phosphoric acid and extracted with acetone. An aliquot of crude extract was re-extracted with hexane and sat. NaCl solution. In the case of tea leaf, solidification processing using ammonium chloride and phosphoric acid was performed before re-extraction with hexane. Clean-up was performed using a silica-gel mini column (500 mg). The LC separation was performed on a C18 column using methanol-water (8 : 2) containing 10 mM ammonium acetate as the mobile phase and MS detection with positive ion electrospray ionization. The calibration curve was linear between 0.002-0.2 µg/mL of hydramethylnon. Recoveries (n=5) of hydromethylnon from 10 kinds of agricultural products fortified at 0.01 µg/g (0.05 µg/g for pineapple) were 82-110%, and their relative standard deviations were 2-12%.

A simple method using high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was investigated for the detection of the antiprotozoal drug imidocarb in 10 livestock and seafood products. Liquid chromatographic separation employed a TSK VMpak-25 column with ammonium acetate-acetonitrile as a mobile phase. Mass spectral acquisition was performed in the ESI positive-ion mode. Imidocarb was extracted from all samples using liquid extraction with acetonitrile under basic conditions. For samples other than honey, fat-soluble impurities were removed by acetonitrile-hexane partitioning. The salting-out technique was used for extraction from honey in order to improve the separation of the organic solvent and water added to the honey sample. The limit of quantitation was 0.005 µg/g (expressed as concentration in samples). The recoveries from all samples were 76-109%, and the repeatability and reproducibility were also satisfactory.

In the inspection of genetically modified rice, rice taxon-specific DNA could not be detected in processed rice food (bifun: rice vermicelli). The effects of using PCR the ratio of rice powder content and temperature of processing on the detection of taxon-specific DNA were examined by means of processing model experiments using cornstarch with 0, 2, 5, 10% rice powder by weight. Cornstarch and rice powder were blended with water and subjected to heating, steam-treatment, and autoclaving. The rice taxon-specific DNA was detectable in 2% rice powder following heat and steam treatments. After autoclaving, rice taxon-specific DNA was detected only in the 10% rice powder product. In the processing model experiment using rice powder, it was found that autoclaving caused severe DNA degradation.

A simple method for the determination of dinoseb in agricultural products by capillary GC without methylation was developed. Dinoseb was extracted from grains and beans with acetonitrile, and the solution was washed with hexane. In the case of fruits and vegetables, dinoseb was extracted with acetone-hexane mixture (1:1), and the solution was washed with water. The extract was cleaned up with a silica gel column, and subjected to NPD-GC with a DB-1 widebore capillary column. Recoveries of dinoseb from agricultural products fortified with 0.05ppm were 79.2-87.8%, and the limit of detection was 0.005ppm.

Systematic determination of organophosphorus, pyrethroid and organonitrogen pesticides in vegetables and fruits by GC was developed. Pesticides were extracted from samples using acetone, and re-extracted into hexane. Organophosphorus pesticides in the extract were directly determined by FPD-GC. For determination of pyrethroid (ECD-GC) and organonitrogen (NPD-GC) pesticides, the extract was purified by Florisil column chromatography using 30% ethyl acetate-hexane.The detection limits were 0.005-0.02ppm for pesticides. Organophosphorus, pyrethroid and organonitrogen pesticides were spiked at 0.1ppm, 0.2ppm and 0.2ppm, respectively. Except for dimethoate, ethiofencarb and lenacil, recoveries of pesticides were over 60%.