Simultaneous determination of perchlorate, thiocyanate, and nitrate contents in urine by UPLC-MS/MS with isotope internal standards

Objective To establish ultra-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for simultaneous determination of perchlorate, thiocyanate, and nitrate in urine.

Methods Urine samples were mixed with a mixture of internal standards of perchlorate, thiocyanate, and nitrate for swirling and high-speed centrifugation, and the supernatants were separated through a column. The contents of perchlorate, thiocyanate, and nitrate were determined by HPLC-MS/MS with the internal standard method.

Results Perchlorate, thiocyanate, and nitrate showed good linearity within the concentration ranges of 1-200 μg/L, 3-600 μg/L, and 1-200 mg/L, respectively, with correlation coefficients of determination (R²) of 0.999, 0.999, and 0.995, respectively. The detection limits of perchlorate, thiocyanate, and nitrate were 0.3 μg/L, 1.0 μg/L and 0.3 mg/L, with the recovery rates of 95.8%-101.7%, 98.4%-104.6%, and 99.3%-100.4%, respectively.

Conclusion This method has the advantages of simple sample pretreatment, short detection time, high specificity for substances to be measured, good stability, and high sensitivity, which can meet the requirements of determining perchlorate, thiocyanate, and nitrate for large quantities of human urine samples.