High performance liquid chromatography-tandem mass spectrum detection method of dithiophosphate pesticide metabolites

Abstract

The invention discloses a high performance liquid chromatography-tandem mass spectrum detection method of dithiophosphate pesticide metabolites, belonging to the detection field of dithiophosphate pesticide metabolites. The method comprises the following steps: carrying out pre-treatment on a sample containing the dithiophosphate pesticide metabolites; carrying out derivatization treatment on the sample by 3-bromo methyl-4-nitrobenzoic acid; and detecting the derivatization products by liquid chromatography-tandem mass spectrum. According to the detection method disclosed by the invention, the recovery rate of the dithiophosphate pesticide metabolites in soil is 79.3-90.7%, the degrees of precision are 9.38% and 5.93%, the detection limits are 0.01mg / kg and 0.005mg / kg, and the linearly dependent coefficients in a range of 0.005-1.000mg / kg are 0.9992 and 0.9997. The method has good recovery rate, limit of quantitation, degree of precision and linearity, and meets the requirements on detection methods of pesticide residues and metabolites thereof in agricultural products.

Description

technical field [0001] The invention relates to a detection method for pesticide metabolites, in particular to a high-performance liquid chromatography-tandem mass spectrometry detection method for dithiophosphate pesticide metabolites, and belongs to the detection field of dithiophosphate pesticide metabolites. Background technique [0002] Organophosphorus pesticides have many advantages such as broad spectrum and high efficiency, and are one of the three pillars of current pesticides. The scale and other factors rank first among all kinds of pesticides (Zhang Qiang. A review of rapid detection methods for organophosphorus pesticides [J]. Guangdong Chemical Industry. 2013, 10(40): 142-147). The wide application of organophosphorus pesticides in agriculture may cause soil , surface water and organisms are polluted and may eventually be passed on to food (Ballesteros, E., & Parrado, M.J..Continuous solid-phase extraction and gas chromatographic determination of organophospho...

AI Technical Summary

Problems solved by technology

The detection methods of trace phosphorodithioate pesticide metabolites mainly include gas chromatography. Due to the unstable structure of metabolites, gas chromatography uses pentafluorobenzylbenzene (PFBBr) to derivatize metabolites, but there are derivatization Long time and low sensitivity (Yang Yulin, Rui Zhenrong, Wang Hong, et al. Analysis of six organophosphorus pesticide metabolites in urine samples by gas chromatography[J]. Chinese Journal of Health Inspection, 2003, 13(1): 24; Wu Chunhua , Zheng Lixing, Zhou Zhijun. Determination of metabolites of organophosphorus pesticides in urine[J]. Fudan Journal, 2006,33(4):552-554); when derivatized with pentafluorobromobenzylbenzene (PFBBr), the hydroxyl Shielding to reduce the activity of O, O-dimethyl phosphorodithioate or O, O-diethyl phosphorodithioate, and then perform gas chromatography-FPD method for detection, the actual measurement of O, O -Dimethyl phosphorodithioate or O,O-diethyl phosphorodithioate have sensitivities of 0.5mg / kg and 1.0mg / kg respectively, much lower than that of liquid chromatography-mass spectrometry

[0005] In addition, O, O-dimethyl phosphorodithioate and O, O-diethyl phosphorodithioate are methylated to trimethyl phosphorothioate and O, O-diethyl-S -Methyl phosphorodithioate (as figure 1 ), the conversion efficiency is not high, and the conversion rate is slow, so the symmetry of the peak shape is not good, the peak shape is not sharp, and it cannot be accurately quantified

[0006] Phosphorodithioate pesticide metabolites are highly polar and cannot be retained by ordinary liquid chromatography columns. Even if HILIC liquid chromatography columns with strong retention for polar compounds are used, it is still difficult to retain and the two compounds cannot be separated. Separation, therefore not directly detectable by liquid chromatography-mass spectrometry

Liquid chromatography-tandem mass spectrometry was used to directly determine phosphorodithioate metabolites, but the chromatographic retention time was too short, and the metabolites could not be completely separated, resulting in too high a matrix effect, and the sensitivity of the actual sample was low (Schenke D..Analytical Method for the determination of O,O-diethylphosphate and O,O-diethylthiophosphate in faecal sample[J].Chemosphere,2000,41:1313-13201; Liu Qian, Xie Mandan, Zhu Yufen. Electrospray ionization mass spectrometry[J]. Journal of Analysis and Testing. 2000,19(5):24-27.)

[0007] In conclusion, when determining phosphorodithioate metabolites (O,O-dimethylphosphorodithioate and O,O-diethylphosphorodithioate) by gas chromatography, bromopentafluorobenzyl As a derivatization reagent, benzene has the disadvantages of long derivatization time and low sensitivity, and this derivatization reagent is not suitable for detection on liquid chromatography-tandem mass spectrometry; the detection method directly using liquid chromatography-tandem mass spectrometry has the disadvantage of being unable to retain, The problem of low sensitivity

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