ABSTRACT
BACKGROUND: To develop an UPLC-MS/MS method to replace the in-house immunoassay for the analysis of urinary cortisol. RESULTS: Cortisol was extracted from human urine by ethyl acetate and analyzed on a Waters ACQUITY TQD system using a BEH C18 column. Linear calibration curves were generated over the range of 27.6 to 1380 nmol/l and exhibited consistent linearity and reproducibility with a correlation coefficient greater than 0.9950. Intra-day coefficients of variation were between 3.74 and 5.10% and inter-day coefficients of variations were between 4.22 and 6.73%. The extraction recovery of cortisol was greater than 83%. CONCLUSION: An accurate, rapid and robust UPLC-MS/MS method for the determination of urinary cortisol has been developed and validated. With a lower flow rate (0.4 ml/min), a shorter running time per sample and a simple and cost-effective sample preparation, this method is a desirable option for clinical laboratories.
