[Simultaneous Determination of Pesticide Residues in Brown Rice Using GC-MS/MS and LC-MS/MS].

This study developed a method that simultaneously detected 283 pesticide residues in brown rice using GC-MS/MS and LC-MS/MS. In this method, we examined the desirable amount of sodium chloride required for salting out and the SPE cartridge required for clean-up. Pesticide residues from the sample were extracted with acetonitrile using a homogenizer and mixed with salts including anhydrous magnesium, two types of citrate, and sodium chloride. The sample solution of the acetonitrile layer was cleaned up using the GCB/NH2 (200 mg/200 mg, 6 mL) SPE cartridge. The determination method was validated using two concentrations (0.01 and 0.1 µg/g) of 283 pesticides based on the validation guideline of the Ministry of Health, Labor and Welfare in Japan. Of the 283 pesticides, 250 were detected satisfactorily. In addition, 59 brown rice samples sold in Tokyo were surveyed using the same method. Out of 44 samples, 12 pesticide residues below MRLs were detected. Therefore, this developed method is useful for the simultaneous determination of pesticide residues in brown rice.

[Evaluation on a Simultaneous Analytical Method of Pesticide Residues in Limes].

A LC-MS/MS simultaneous analytical method for screening 191 pesticide residues in limes had been developed and validated. Pesticides were extracted with acetonitrile from samples. Then mixed salts, which were anhydrous magnesium sulfate for dehydration, sodium carbonate for adjusting pH, and sodium chloride for salting out, were added to the sample. After centrifugation, supernatant was transferred to a tube. The sample solution was cleaned up using solid phase extraction (SPE) with C18/GC/PSA for the determination by LC-MS/MS. The developed method was improved the recovery rate of thiabendazole, which had a low recovery rate by the conventional method. Validation study, which was following the guidelines of the Ministry of Health, Labor and Welfare, were carried out at 0.01 and 0.1 µg g-1 to evaluate the method. The results of 175 pesticides out of 191 were with satisfactory. A total of 19 imported lime samples sold in Tokyo was analyzed to evaluate the method, then 18 samples contained pesticide residues below MRLs. The developed method is applicable for detection of pesticide residues in lime.

[Comparison of Validation Results Obtained by GC-MS/MS and LC-MS/MS for the Analysis of Residual Pesticides in Agricultural Products].

In the field of food analysis and regulation, different instruments are used to determine the accuracy of quantification values. This is essential, as inconsistencies in values are commonly encountered. To visualize the degree of these discrepancies in each food matrix, we compiled a validation study based on a routine method developed in our laboratory, for 121 pesticides in six agricultural products, namely the grapefruit, potato, paprika, cabbage, spinach, and brown rice. These were analyzed by GC-MS/MS and LC-MS/MS, and the results were compared mainly on the basis of trueness. According to the results of the validation study when using GC-MS/MS, of the 121 pesticides tested in each product class, the number of analytes that satisfied the criteria of the Japanese validation guidelines was 97 in grapefruit, 111 in potato, 110 in paprika, 118 in cabbage, 111 in spinach, and 63 in brown rice. In contrast, in the analysis of the same samples by using LC-MS/MS, the number of analytes that satisfied the criteria of the validation guidelines was 50 in grapefruit, 114 in potato, 103 in paprika, 112 in cabbage, 100 in spinach, and 103 in brown rice. Inconsistences in the differences of trueness were mainly attributed to matrix effects of each instrument, as well as to food matrices, of which the most diverged matrix was that of brown rice (over 20%).

[Validation of a Method for Determining Multiple Residual Pesticides in Dried Red Pepper Using LC-MS/MS].

An analytical method has been developed and validated for determining 107 pesticide residues in dried red pepper using LC-MS/MS. LC method, the clean-up and sample dilution processes were examined to determine their impact on reducing the matrix effects. Clean up was performed using an ENVI-CarbIITM/PSA (300/600 mg, 6 mL) SPE cartridge. In the sample dilution process, eight-fold dilution was used. In the validation of the developed method at two concentrations (0.01 and 0.1 µg/g) for 107 pesticides, 96 pesticides showed recovery rates in the range of 70.1 to 112.6%, RSDs of repeatability of ≤11.5 and 3.4%, and RSDs of within-laboratory reproducibility of ≤24.3 and 19.9%. These values fulfill the criteria of the validation guidelines for pesticide residues in Japan. It is concluded that matrix effects and low recovery rates in the process of extraction are the main factors for values that do not conform to the criteria.

Surveillance of Chlorantraniliprole Residues in Vegetables and Fruits Using LC-MS/MS.

We measured the residual amounts of chlorantraniliprole in various vegetables and fruits. Sample solutions were prepared according to our routine procedure based on the QuEChERS method and analyzed by LC-MS/MS. Performance characteristics were evaluated for 8 kinds of food samples by means of recovery tests of 5 replicates at the concentration of 10 ng/g. Recoveries and RSDs (％) ranged from 50.2 to 93.4％ and from 2.1 to 9.7％, respectively. Application of this method to survey 207 vegetables and 163 fruits gave detection rates of 8.2 and 1.2％, respectively. In vegetables, detection rates were high in okra (4 out of 10 samples), paprika (4 out of 23 samples) and tomato (2 out of 6 samples), and leaf vegetables such as lettuce, mizuna, spinach and wrinkled greens also contained high concentrations of chlorantraniliprole. The highest residual concentration was 571 ng/g in mizuna. The samples containing chlorantraniliprole seemed to be mainly from Asian countries, including samples of domestic Japanese origin. However, none of them contained more than the MRL, which suggests that the use of chlorantraniliprole has been properly controlled.

Determination of Formetanate Hydrochloride in Agricultural Products by LC-MS/MS.

An analytical method based on LC-MS/MS was developed for the determination of formetanate hydrochloride in agricultural products. Formetanate hydrochloride was confirmed to be stable in acetonitrile. It was therefore extracted from samples with acetonitrile, and the crude extracts were purified using a combination of ethylenediamine-N-propyl silylation silica gel and graphite carbon mini columns. Formetanate hydrochloride in the resulting sample solutions was quantified by LC-MS/MS utilizing an external solvent calibration curve. The average recovery (n=5) of formetanate hydrochloride spiked in 10 types of agricultural products (brown rice, soybean, spinach, cabbage, potato, apple, orange, lime, nectarine and green tea) at the maximum residue limits (MRLs) or at a uniform limit of 0.01 mg/kg was 92.3-103%, with a relative standard deviation of 1.3-5.4%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.

Determination of Fluopicolide in Livestock Products and Seafood by LC-MS/MS.

An analytical method for the determination of fluopicolide in livestock products and seafood was developed using LC-MS/MS. Sodium chloride was added to livestock products and seafood samples and fluopicolide was extracted twice with acetone after acidification with formic acid. The fat from the crude extract was removed using a macroporous diatomaceous earth column, followed by purification with a combination of mini-columns of GC (graphite carbon) and PSA (ethylenediamine-N-propyl silylation silica gel). The average recovery (n=5) of fluopicolide from 10 types of livestock products and seafood (cattle fat, cattle liver, cattle muscle, chicken, eel, egg, freshwater clam, honey, milk and salmon) spiked at the MRLs or at the uniform limit (0.01 ppm) was 96-100%, with a relative standard deviation of 2.3-6.2%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.

[Single-laboratory validation study of simple and simultaneous determination method for pesticide residues in meat by LC-MS/MS].

We performed a single-laboratory validation study of a simple and simultaneous determination method for pesticide residues in meat using LC-MS/MS. Water was added to the sample and the mixture was homogenized. Next, pesticides were extracted with acetonitrile containing 1 vol% formic acid using a homogenizer, and salted out with magnesium sulfate, trisodium citrate and sodium chloride. After centrifugation, the acetonitrile layer was made up to standard volume and analyzed by LC-MS/MS. This method was assessed by performing recovery tests in retail bovine, swine and chicken muscle samples spiked with the 132 pesticides at the levels of 0.01 and 0.04 µg/g. Among them, 125 pesticides satisfied the Japanese method validation guideline criteria in bovine, 120 in swine and 127 in chicken.

[Survey of pesticide residues in imported spices and herbs (1997.4-2011.3)].

A survey of pesticide residues in 313 samples of imported spices and herbs on the Tokyo market from April 1997 to March 2011 was carried out. Thirty-seven kinds of pesticides, including organophosphorus, organochlorine, pyrethroid, carbamate and others, were detected between levels of trace (below 0.01 ppm) and 3.3 ppm from 64 samples. The rate of detection was highest in peel (100%) followed by stem (66.7%), fruit (34.5%), bark (33.3%), flower (31.3%) and leaf (14.7%). No residues were detected in root, seed or whole grass. Organochlorine pesticides were detected in all plant parts. The insecticides were detected in products from all production areas, suggesting that their use is common. Residue levels of these pesticides were calculated as less than 1% of their ADI values, based on the daily intake of spices and herbs. Therefore, these spices and herbs should be safe when consumed in customary amounts.

[Survey of pesticide residues in imported tea (1992.4-2010.3)].

A survey of pesticide residues in 116 imported tea samples on the Tokyo market from April 1992 to March 2010 was carried out. Twenty-two kinds of pesticides, including organophosphorus, organochlorine, pyrethroid and others, were detected at levels between trace (below 0.01 ppm) and 4.0 ppm in 76 samples. The rate of detection was 90% in non-fermented tea, 89% in semi-fermented tea, and 49% in fermented tea. Organophosphorus pesticide was not detected in puer tea, which is fermented with bacteria. The pesticide residues tended to be decreased by a fermentation process. However, organochlorine and pyrethroid pesticides appeared to be chemically stable, so they were still detected in fermented teas. Residue levels of these pesticides were calculated as less than 1% of ADI, except for ethion (45% of ADI) based on the daily intake of tea. Therefore, these teas should be safe when drunk in customary amounts.

[Study on rapid analysis method of pesticide contamination in processed foods by GC-MS and GC-FPD].

A simple and rapid method using GC-MS and GC-FPD for the determination of pesticide contamination in processed food has been developed. Pesticides were extracted from a sample with ethyl acetate in the presence of anhydrous sodium sulfate, then cleaned up with a combination of mini-columns, such as macroporous diatomaceous earth, C18, GCB (graphite carbon black) and PSA. Recovery tests of 57 pesticides (known to be toxic or harmful) from ten kinds of processed foods (butter, cheese, corned beef, dried shrimp, frozen Chinese dumplings, grilled eels, instant noodles, kimchi, retort-packed curry and wine) were performed, and the recovery rates were mostly between 70% and 120%. This method can be used to judge whether or not processed foods are contaminated with pesticides at potentially harmful levels.

[Survey of pesticide residues in imported frozen vegetables and fruits (1989.4~2008.3)].

A survey of pesticide residues in 595 imported frozen products on the Tokyo market from April 1989 to March 2008 was carried out. Forty three kinds of pesticides, including organophosphorus, organochlorine, carbamate, pyrethroid and others, were detected between levels of trace (below 0.01 ppm) and 4.6 ppm from 162 samples. Chlorpyrifos, cypermethrin and omethoate were frequently detected in green vegetables (komatsuna leaf and spinach), cypermethrin and methamidophos were detected in pods and seeds (green soybean and string pea), chlorpropham (CIPC) was detected in potato, and captan and carbaryl were detected in berries (blueberry, raspberry and strawberry). The hydrophilic pesticide methamidophos was detected in flesh of lychee. Residue levels of these pesticides were calculated as between less than 0.5% and 30% of their ADI values according to the daily intake of frozen products. Therefore, these frozen products should be safe when they were eaten in customary amounts.

[Transfer of pesticide residues to crops via cardboard boxes].

Cardboard boxes used to transport crops are often reused in the distribution process, and therefore transfer of pesticides between crops might occur. So, we designed model experiments to investigate whether or not transfer of pesticide residues from crops to other crops via cardboard boxes occurs. Under severe experimental conditions, 6.2% of the pesticide residues of grapefruit was found to be transferred to spinach via cardboard boxes. In the case of the mandarin orange, 0.57% was transferred. The actual amount of transferred pesticides in the market may be less than that in these model experiments, but it is clear that transfer of pesticide residues to other crops via cardboard boxes can occur. Therefore more attention must be given to reuse of cardboard boxes in the distribution process.

[Survey of pesticide residues in imported fruit products (1994.4-2006.3)].

A survey of pesticide residues in 600 imported fruit products on the Tokyo market from April 1994 to March 2006 was carried out. Thirty kinds of pesticides, including organophosphorus, organochlorine, carbamate, and pyrethroid, were detected between levels of Tr (below 0.01 ppm) to 0.37 ppm from 75 samples. Residual pesticides were detected from fruit products, dried fruits and pressed juice. A high frequency of pesticide residues was observed in peels, whole body of fruits and products which contained them. Residue levels of these pesticides were calculated as between less than 0.1 and 3.9% of their ADI values according to the daily intake of fruit products. Therefore, these fruit products should be safe when eaten in customary amounts.

[Survey of pesticide residues in imported vegetable products (1992.4-2006.3)].

Pesticide residues in 165 imported vegetable products on the Tokyo market from Apr. 1992 to Mar. 2006 were investigated. Seven kinds of pesticides were detected at levels between Tr (below 0.01 ppm) and 1.0 ppm from 16 samples. There was no sample in which pesticide residues exceeded the MRLs. The salt leaf of grape imported from Greece contained chlorpyrifos and quinalphos, and there was some doubt as to whether the residue levels exceeded the MRLs when the Japanese positive list system for pesticide residues in food was applied. Pesticides were detected from pickles and dehydrated vegetable, but not from products that had been treated with heat and water, such as boiled vegetables and purees. Many samples of products from Asia, and North America area contained detectable levels of pesticides. Residue levels of these pesticides were calculated as between 0.006 and 20.3% of their ADI values according to the daily intake of vegetable products. Therefore, these vegetable products should be safe when eaten in a normal manner.

[Determination of hymexazol in agricultural products by GC-NPD].

A method for the determination of hymexazol in agricultural produdcts by gas chromatography with a highly sensitive nitrogen-phosphorus detector (GC-NPD) was investigated. Hymexazol was extracted with acetonitrile, and the acetonitrile layer was separated by salting-out. The water layer was loaded onto a Chem-Elut column. Hymexazol in the water layer was adsorbed on the column, and eluted with ethyl acetate. The acetonitrile layer and the eluate were mixed and evaporated. The residue was dissolved in ethyl acetate, and the sample solution was cleaned up on a C18 column. Hymexazol in the eluate was analyzed by GC-NPD with a high-polarity capillary column (DB-FFAP) and highly deactivated inlet liner. Recoveries of hymexazol spiked in agricultural products (tomato, lemon, soybean and other samples) at the level of 0.1 mug/g ranged from 65.0 to 84.7%. The limit of detection was 0.02microg/g.

[Survey of pesticide residues in imported cereal products (1994.4 approximately 2006.3)].

A survey of pesticide residues in 490 imported cereal products on the Tokyo market from April 1994 to March 2006 was carried out. Eight kinds of organophosphorus pesticides (chlorpyrifos, chlorpyrifos-methyl, DDVP, diazinon, etrimfos, malathion, MEP and pirimiphos-methyl) were detected at levels between Tr (below 0.01 ppm) and 0.82 ppm from 91 samples. In our investigations, chlorpyrifos-methyl and malathion tended to be detected in samples from America, pirimiphos-methyl in those from Europe, and MEP in those from Oceania. Thus, pesticide residues seemed to be different in produce from different areas. Residue levels of these pesticides were calculated as between 0.08 and 13.2% of their ADI values according to the daily intake of cereal products. Therefore, these cereal products should be safe for normal usage.

Clean-up method of forchlorfenuron in agricultural products for HPLC analysis.

A simplified method for the determination of forchlorfenuron in agricultural products by HPLC with UV detection was investigated. A chopped sample homogenate from agricultural products was extracted with acetone. The extract was filtrated and concentrated. The residues was loaded onto a Chem Elut column and extracted with ethyl acetate. The crude extract was purified on Oasis HLB and Bond Elut PSA mini-columns using a mixture of methanol and ethyl acetate. Forchlorfenuron was analyzed by HPLC with UV detection (263 nm). HPLC separation was performed on an ODS column with methanol-water as the mobile phase. Recoveries of forchlorfenuron from several agricultural products fortified at the level of 0.1 microg/g were in the range of 87.6-99.5%. The limit of detection (S/N=3) was 0.005 microg/g in the sample.

[Survey of pesticide residues in rice (April, 1995-March, 2005)].

Pesictide residues in 343 samples of domestic rice and 32 samples of imported rice purchased on the Tokyo market from April 1995 to March 2005 were investigated. Residues of eleven kinds of pesticides (including organophosphorus, organochlorine, carbamate, pyrethroid and organonitrogen pesticides and bromide) were detected at levels between trace and 1 ppm in 47 domestic rice samples. DDVP and bromide residues were detected at levels between 0.01 ppm and 5 ppm in 18 imported rice samples. For rice samples that were found to containing pesticides, the amounts of pesticide intake were calculated according to the daily intake of rice, and they were compared with the ADI values. Since residual pesticide levels were 17/10,000-2/5 of ADI, all the rice samples were considered to be safe for human consumption.

[Survey of pesticide residues in baby foods (1999.4-2005.6)].

A survey of pesticide residues in 316 baby foods on the Tokyo market from April 1999 to June 2005 was carried out. Fifteen kinds of pesticides, including organophosphorus, organochlorine, carbamate, pyrethroid and others, were detected between at levels Tr (below 0.01 ppm) and 0.55 ppm from 28 samples. The baby foods in which residual pesticides were detected were produced from flour, leaf vegetable and fruits. The pesticides were detected in baby foods produced with minimal processing, such as straining and squeezing. For the baby foods containing pesticides, the amounts of intake of the pesticides were calculated from the recommended servings, and compared with the ADI values. Residual pesticide levels in baby food were between 0.06 and 16.6% of the ADI. Therefore, these foods should be safe in normal usage.