[Residual pesticide concentrations after processing various types of tea and tea infusions].

The effects of processing to produce various types of tea or infusion on the levels of pesticide residues in tea were investigated for three insecticides (chlorfenapyr, pyrimiphos-methyl, and clothianidin). Tea plants were sprayed with one of the three pesticides and cultivated under cover. The levels of pesticide residues in tea decreased after processing according to the time and temperature of heating, as well as fermentation.

[New clean-up method with dispersive solid-phase extraction for simultaneous determination of pesticide residues in livestock products by GC-MS/MS].

A simple clean-up method was developed for the simultaneous determination of pesticide residues in livestock products by GC-MS/MS. The pesticide residues were extracted with acetonitrile-ethanol (1 : 1), and matrix components such as adipose were effectively eliminated by a combination of refrigerated centrifugation, dispersive solid-phase extraction, and multifunctional column chromatography. In this method, samples are treated quickly and easily without the need for gel-permeation chromatography.

[Quick simultaneous determination of residual veterinary drugs in processed food].

Development of rapid and high accuracy analysis, and tightening of regulations for veterinary drugs are required because many examples of detection of veterinary drugs in many kinds of processed food have been reported. In this study, we constructed an improved method for simultaneous determination of veterinary drugs, based on the glass bead homogenization method with EDTA-2Na and batch purification for QuEChERS analysis. Our extraction procedure is suitable for handling multiple samples quickly and easily.

[Study of simultaneous determination of residual veterinary drugs including tetracycline antibiotics in milk and dairy products].

It is considered to be difficult to detect tetracycline antibiotics in all-at-once simultaneous analysis with other drugs by liquid chromatography with tandem mass spectrometry, because tetracycline antibiotics chelate with bivalent metal ions such as calcium in samples. Therefore, we studied simultaneous determination of tetracycline antibiotics after removal of calcium with disodium ethylenediaminotetraacetate (EDTA-2Na). Tetracycline antibiotics could be assayed in all-at-once analysis by adding EDTA-2Na during the extraction procedure.