Effects of processing and cooking on the reduction of dinotefuran concentration in Japanese rice samples.

Dinotefuran is an insecticide belonging to the neonicotinoid class, which is frequently used to control pests in paddy rice owing to its permeability and effectiveness against sucking insects. Since 2002, this insecticide has been commercially available in Japan, and has become controversial due to its high detection frequency in brown rice for primary consumption. In this study, the effects of processing and cooking on the reduction of dinotefuran residues in commercially available brown rice were investigated.

Juvenile hormone-independent function of Krüppel homolog 1 in early development of water flea Daphnia pulex.

Elaborate regulation of insect metamorphosis is the consequence of physiological cooperation among multiple endocrine factors such as juvenile hormones (JHs) and ecdysteroids. Hormone-induced transcription factors play important roles in substantive interactions between hormonal signaling pathways. In insects, zinc finger transcription factor Krüppel homolog 1 (Kr-h1) is a key gene of the endocrine signaling pathway in which it is directly upregulated by JH receptor Methoprene-tolerant (Met) in the presence of JH and then regulates multiple downstream factors, including components of the ecdysteroid signaling pathway.

[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.

[Simultaneous determination of pesticide residues in agricultural products by LC-MS/MS].

A method for the simultaneous determination of multiple pesticide residues in agricultural products was developed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The sample was extracted with acetonitrile. Co-extractives were removed by GPC/graphitized carbon column SPE, and silica gel/PSA cartridge column SPE.

[Analysis of spinosad in animal and fishery products by LC-MS].

We investigated the determination of spinosyn A and spinosyn D, the active ingredients of spinosad, in animal and fishery products by liquid chromatography with mass spectrometry (LC-MS). The sample was homogenized with 1 mol/L dipotassium hydrogenphosphate aqueous solution and extracted with acetone-n-hexane under mildly alkaline conditions. After n-hexane-acetonitrile partitioning using an EXtrelut(®) column, the extract was cleaned up on a tandem SAX/PSA mini-column, and examined by means of fragmenter-voltage-switching ESI-SIM mode LC-MS.

[Multiresidue analysis of PCB, organochlorine pesticides and chlordanes in marine products by GC-micro ECD].

A multiresidue method using dual-injection, dual-column, and dual-micro electron capture detection gas chromatography (dual-column GC-µECD) was developed for the determination of PCB, organochlorine pesticides and chlordanes in marine products. The sample was extracted with hexane-acetone (2 : 1), and the extract was cleaned up by gel permeation chromatography(GPC)/solid-phase extraction (SPE). The GPC fraction was selectively collected, and loaded directly onto a graphitized carbon/PSA 2-layered column.