Non‐competitive immunoassay for luteinizing hormone in human serum using capillary electrophoresis with chemiluminescence detection

A non‐competitive immunoassay based on capillary electrophoresis (CE) with chemiluminescence (CL) detection has been developed for the determination of luteinizing hormone (LH) in human serum. The work involved the development of separation and CL conditions, allowing for routine analysis of serum samples. In this study, horseradish peroxidase (HRP)‐labelled monoclonal anti‐LH can catalyse the luminol–hydrogen peroxide reaction. The determined LH can react with excessive amount of HRP‐labelled anti‐LH. Within 14 min, free enzyme conjugate and immune complex could be separated in alkaline borate buffer by means of a high voltage (15 kV). To improve sensitivity, a series of measures were adopted, including the choice of para‐iodophenol as a CL enhancer, unique design in detect window. Under the optimal conditions, the calibration curve for LH was established in the concentration range 1–200 mIU/mL and the detection limit was 0.08 mIU/mL. Compared with ELISA, this method decreased the detection limit by about 12 times, and it has been successfully employed in the determination of LH in human serum. Copyright © 2007 John Wiley & Sons, Ltd.