【求助】各位有谁知道矮壮素的LC/MS/MS的测定方法

Analysis of Chlormequat residues in grain using liquid chromatography-mass spectrometry ($$lc-MS/MS)
摘要

A fast, sensitive and specific method for routine determination of residues from Chlormequat (CAS no. 7003-89-6) is described. The method is based on a simple clean-up using an SPE-C18 cartridge, high-performance liquid chromatography on a standard C18 column (Spherisorb S5 ODS1) and specific detection and quantification by electrospray mass spectrometry ($$lc-MS/MS). 13C-Chlormequat was synthesised for use as internal standard. Samples were extracted with methanol - water - acetic acid. Internal standard and ammonium acetate were added before C18-cartridge clean up and residues eluted with methanol - water - acetic acid, containing 50 mM ammonium acetate. Chromatographic separation was achieved using a solvent composed of acetonitrile - methanol - water - acetic acid (53:21:25:1 by volume), containing 50 mM ammonium acetate. Electrospray ionisation mass spectrometry was employed using m/z 58 (daughter ion of the Chlormequat quaternary ammonium ion, m/z 122) and m/z 61 (daughter ion of the 13C-Chlormequat quaternary ammonium ion, m/z 125) for quantification. The $$lc analysis time was 15 min and the limit of detection of the analytical method was 9 wg/kg. The performance of the method was demonstrated analysing grain material from an inter-comparison study. In Denmark the primary use of Chlormequat chloride (CCC, cycocel, or chlorocholin chloride, CAS no. 999-81-5) is for winter cereals and 11 such winter wheat samples from the Danish National Pesticide Survey were analysed. Residue contents were from below 0.01 up to 0.45 mg/kg, and thus below the EU maximum residue level of 2.0 mg/kg for wheat.

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