Quantitative analysis of skeletal symmetric chlorhexidine in rat plasma using doubly charged molecular ions in LC-MS/MS detection

The skeletal-symmetric structure of chlorhexidine predicts that each doubly charged molecular ion may generate two para-chlorbenzenguanidines daughter ions through bond Cleavage at two protonation sites, thus generating better sensitivity in MRM transition than that involving singly charged molecular ions. This unique nature can be used to improve sensitivity of LC-MS/MS method. Results: High-throughput LC-MS/MS was developed and validated to quantify chlorhexidine in rat plasma as low as 0.500 ng/ml. In the method, a unique chromatographic method on a narrow bore column reduced run time to 2.5 min and successfully minimized high background from accumulation of endogenous compounds in matrix on the column. Conclusion: This method was proved to be robust and suitable to support rat dermal toxicology studies.