[Determination of 1, 4-dioxane in aerosol cosmetic by new isotope dilution-headspace gas chromatography-mass spectrometry].

Objective: To develop a simple, fast and sensitive analytical method based on isotope dilution-headspace gas chromatography-mass spectrometry for the determination of 1, 4-dioxane residue in the aerosol cosmetics.

Methods: Sample was successive weighed and dissolved in 1, 3-dimehyl-2-imidazolidinone(DMI)solvent and isotope internal standard was added. Then transfered to a 20 mL headspace vial.

[Determination of 34 pesticide residues in rice, proso millet and wheat with QuEChERS-on line gel permeation chromatography-gas chromatography-mass spectrometry].

A method for the simultaneous determination of 34 pesticides in rice, proso millet and wheat by QuEChERS coupled with on line gel permeation chromatography-gas chromatography-mass spectrometry (GPC-GC-MS) was developed. The effects of the sample weight, extraction solvent, sorbent for purification were investigated. The matrix effect and the usefulness of analyte protectant were also studied.

[Rapid simultaneous screening and detection of ten anticoagulant rodenticides in foods by ultra-high performance liquid chromatography-tandem mass spectrometry].

A rapid method for the simultaneous screening and detection of ten anticoagulant rodenticides in foods was developed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After the extraction by acetonitrile and clean-up by QuEChERS, the extract was separated on a Poroshell 120 EC-C18 column (100 mm x 2.1 mm, 2.