Determination of deltamethrin and its toxicity biomarkers in rabbit urine by high performance liquid chromatography-tandem mass spectrometry

A method was developed for the determination of biomarkers related to toxicity of deltamethrin in rabbit urine by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The target analytes in this method are as follows : deltamethrin and its two metabolites (1R-cis )-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropane carboxylic acid (dibromochrysanthemic acid) and 3-phenoxybenzoic acid (3-PBA), and five toxic biomarkers, viz. serotonin hydrochloride (5-HT), 5-hydroxyindole-3-acetic acid (5-MAA), 3-nitropropionic acid (3-NPA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and 6-methoxyguanine. Urine samples were cleaned by matrix solid-phase dispersion extraction (MSPD) with diatomite; and protein was precipitated with trichloroacetic acid; and then the sample solutions were purified with hydrophilic-lipophilic balance (HLB) solid-phase extraction cartridges. The biomarkers were analyzed with electrospray ionization (ESI) in a positive and negative switching scan mode, in which the positive scan mode was used for deltamethrin, 5-HT, 5-HIAA, 8-OHdG, and 6-methoxyguanine, and the negative scan mode was used for (1R-cis)-3-(2,2-dibromoethenyl)2,2-dimethylcyclopropane, 3-PBA, and 3-NPA. The target compounds were quantified with the external standard using matrix calibration curves. The linear regression curves of the eight target compounds were linear with correlation coefficients no less than 0.991 4. The LOD and LOQ of 5-HIAA were 20 mu g/L and 50 mu g/L, respectively, and the LODs and LOQs of the other analytes were 0.2-5.0 mu g/L and 0.5-10 mu g/L, respectively. The average recoveries of the analytes spiked in rabbit urine ranged from 74.2% to 98. 7% at three levels, with relative standard deviations (RSDs) no more than 12%. The method was simple, fast, accurate, sensitive, and suitable for the detection for the exposure evaluation of deltamethrin.