[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.

[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.