Creatinine is an important diagnostic marker and is also used as a standardization tool for the quantitative evaluation of exogenous/endogenous substances in urine. This study aimed at evaluating and comparing three analytical approaches, based on hyphenations of different separation [two-dimensional capillary isotachophoresis (CITP-CITP), capillary zone electrophoresis (CZE), ultra-high-performance liquid chromatography (UHPLC)] and detection [conductivity (CD), ultraviolet (UV), tandem mass spectrometry (MS/MS)] techniques, for their ability to provide reliable clinical data along with their suitability for the routine clinical use (cost, simplicity, sample throughput). The developed UHPLC-MS/MS, CITP-CITP-CD, and CZE-UV methods were characterized by favorable performance parameters, such as linearity (r ˃ 0.99), precision (relative standard deviation, 0.22-2.97% for the creatinine position in analytical profiles), and recovery (87.1-115.1%). Clinical data, obtained from the analysis of 24 human urine samples by a reference enzymatic method, were comparable with those obtained by the tested methods (Passing-Bablok regression and Bland-Altman analysis), approving their usefulness for the routine clinical use. In this context, the UHPLC-MS/MS method provides benefits of enhanced orthogonality/accuracy and high sample throughput (threefold shorter total analysis times than the CE methods), whereas advantages of the CE methods for routine labs are simplicity and low cost of both the instrumentation and measurements.
Keywords: capillary isotachophoresis; capillary zone electrophoresis; clinical analysis; creatinine; mass spectrometry; ultra-high-performance liquid chromatography.
© 2020 John Wiley & Sons, Ltd.