Urinary Cortisol Quantitation Using Ultra High Pressure Liquid Chromatography/Compact Mass Spectrometry

Introduction

Cortisol is an important steroid hormone produced from cholesterol in the adrenal cortex. Its secretion is closely regulated by the Adrenocorticotropic hormone (ACTH). Most cortisol is protein-bound and only unbound cortisol is excreted in urine. The measurement of cortisol in urine is typically used to diagnosis of Cushing’s syndrome, a disorder of hypercortisolism.

Although immunoassay methods have extremely high sensitivity, they are subject to variable interferences from other steroids and their conjugates. Liquid chromatography with tandem mass spectrometry is used in clinical analysis because of its higher specificity and selectivity than immunoassay methods.

A simple and robust UHPLC/MS method using the Advion Interchim Scientific expression^® Compact Mass Spectrometer (CMS) is introduced for urinary cortisol analysis and the dynamic range and sensitivity (LOD and LLOQ) of the UHPLC/CMS method will be evaluated.