Simultaneous Determination of 6β-Hydroxycortisol and 6β-Hydroxycortisone in Human Urine by LC with UV Absorbance Detection

A liquid chromatographic method for the simultaneous determination of 6 beta-hydroxycortisol and 6 beta-hydroxycortisone using dexamethasone as internal standard in human urine is described. Separation was achieved on a reversed-phase C18 column by a gradient elution of acetonitrile and water containing 0.1% formic acid. 6 beta-Hydroxycortisol and 6 beta-hydroxycortisone were monitored by UV absorption at 244 nm. The lower limits of quantitation were 5 ng mL(-1) for both analytes. The intra-day and inter-day relative standard deviations were less than 7.4%. Accuracy determined at three concentrations ranged between 92.16 and 109.77%. The sensitivity, specificity and accuracy of this method were demonstrated to be satisfactory for measuring both metabolites in human urine.