Abstract:

A new and sensitive analytical method has been developed for the simultaneous determination of seven anticoagulant rodenticides in whole blood and urine samples by liquid chromatography-linear ion trap mass spectrometry (LC-LIT/MS) with on-line solid phase extraction (on-line SPE). The samples were treated with acetonitrile, followed by dilution, centrifugation, and filtration. The resulting solution was injected into the LC system directly and processed by on-line SPE column for enrichment and purification. Separation was performed on a C18 column with mixed mobile phases of methanol and 0.02 mol/L ammonium acetate aqueous solution for gradient elution. The analytes were detected by the mass spectrometer with electrospray ionization (ESI) in negative mode. MS² full scan signals of the target parent ions within the locked retention time window were recorded. Self-built database searching was performed for qualitative confirmation, and MS² fragment ions with high sensitivity and specificity were selected for quantification. Simultaneous qualitative and quantitative analyses of the seven rodenticides were achieved in this way. Good linearities were obtained within the investigated mass concentration ranges of the seven rodenticides, with r²≥0.9958 in blood and r²≥0.9946 in urine. The LODs varied from 0.02 ng/mL to 1.00 ng/mL, and the LOQs varied from 0.10 ng/mL to 4.00 ng/mL. The recoveries at three spiked levels in blood and urine samples ranged from 81.0% to 113.9%, with RSDs of 0.1%-6.2% (n=6). The developed method is simple, sensitive, and can be used for the rapid detection and accurate quantification of the seven anticoagulant rodenticides in whole blood and urine samples.

Key words: anticoagulant rodenticides, liquid chromatography-linear ion trap mass spectrometry (LC-LIT/MS), on-line solid phase extraction (on-line SPE), urine, whole blood