Novel LC–MS/MS method devised for the determination of urea in human epithelial lining fluid

Method comprising simple derivatization achieves accurate and precise LC–MS/MS analysis of urea.

Researchers at GSK, based in King of Prussia (PA, USA), have reported on a sensitive, selective and quantitative method for the determination of urea in human epithelial lining fluid (ELF).

Developed by Chester Bowen and Hermes Licea-Perez, researchers in GSK’s Bioanalytical Science and TK department, the method comprises the simple derivatization of urea using camphanic chloride, which improves chromatographic retention and separation.

According to the report, prior to performing derivatization, the team first dried a 20-μl aliquot of ELF, without initial sample clean-up. UHPLC, coupled to MS/MS, was then used for chromatographic separation and subsequent determination of urea.

Bowen and Licea-Perez validated the method over the concentration range of 8.78–103.78 μg/ml, reporting that the dynamic range may be further lowered if required.

The team also investigated how the derivatization method compared with a commercially available colorimetric assay kit and trialled the method in a preclinical non-GLP mouse study, where urea measurements were used as marker of bronchoalveolar lavage fluid dilution.

The report concluded that the novel method provides a rugged, precise and accurate approach to the analysis of urea in ELF samples. In addition, the small sample volume and run time of 1.5 min allows for high-throughput analysis of urea.

Source: Bowen C, Licea-Perez H. Development of a sensitive and selective LC–MS/MS method for the determination of urea in human epithelial lining fluid. J. Chromatogr. B Analyt Technol. Biomed. Life Sci. 917–918, 24–29 (2013).