[Analysis of metribuzin and its metabolites in livestock products and seafoods by liquid chromatography-tandem mass spectrometry]

Ionic Liquid Modified Porous Polymer as a Dispersive Filter Extraction Adsorbent for Simple, Sensitive, and Efficient Determination of Chlorotriazine Herbicides in Irrigation Water

Triazine herbicides (TRZHs) are widely used in agricultural production, but their improper use can threaten the environment and organisms. Herein, rapid extraction of four chlorotriazine herbicides (Cl-TRZHs) in irrigation water was achieved using an ionic liquid modified porous m-aminophenol formaldehyde resin (IL-MAPFR) as a dispersive filter extraction (DFE) adsorbent. The IL-MAPFR shows excellent adsorption performance for four Cl-TRZHs (simazine, cyanazine, atrazine, and terbuthylazine), with a large specific surface area (158.1 m² g^-1) and fast mass transfer (2 min). The adsorption process conforms to the pseudo-second-order kinetics and Freundlich isotherm models. The four Cl-TRZHs were concentrated 12-16-fold after the IL-MAPFR-DFE method. Coupled with high-performance liquid chromatography, an accurate and sensitive determination method for four Cl-TRZHs in irrigation water was established, with low detection limit (0.11-0.20 ng mL^-1), high recoveries (91.5-110%), and excellent precision (relative standard deviations (RSDs) ≤ 8.4%). This method provides technical support for agricultural irrigation water quality monitoring and has great application potential in water safety, especially pesticide residues.

[A Simultaneous Determination Method with Acetonitrile-n-Hexane Partitioning and Solid-Phase Extraction for Pesticide Residues in Livestock and Marine Products by GC-MS]

A simultaneous determination method was examined for 312 pesticides (including isomers) in muscle of livestock and marine products by GC-MS. The pesticide residues extracted from samples with acetone and n-hexane were purified by acetonitrile-n-hexane partitioning, and C18 and SAX/PSA solid-phase extraction without using GPC. Matrix components such as cholesterol were effectively removed. In recovery tests performed by this method using pork, beef, chicken and shrimp, 237-257 pesticides showed recoveries within the range of 70-120% in each sample. Validity was confirmed for 214 of the target pesticides by means of a validation test using pork. In comparison with the Japanese official method using GPC, the treatment time of samples and the quantity of solvent were reduced substantially.