Advancing clinical liquid chromatography-mass spectrometry analysis: Rational design and optimization of derivatization techniques for enhanced sensitivity and throughput

Clinical laboratories are engaged in early disease diagnosis, health status monitoring, and clinical outcome prediction through the analysis of small-molecule analytes, thereby facilitating precise clinical decision-making. In comparison with immunoassays, liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods provide enhanced detection coverage, sensitivity, and specificity, and also improve comparability between laboratories. Their utilization has markedly increased across various clinical conditions. However, certain small-molecule analytes in clinical laboratory studies exhibit limited stability during sample storage or pretreatment and demonstrate poor detection sensitivity and specificity in LC-MS/MS analysis due to complex matrices and other factors, such as lack of an easily ionizable group. Chemical derivatization has emerged as a straightforward and efficient tool to facilitate the LC-MS/MS analysis of certain analytes since the introduction of butylation of amino acids for neonatal screening. This review focuses on discussing chemical derivatization-based LC-MS/MS methods for small-molecule analyte screening in traditional clinical laboratories. Nearly 20 years of publications on this topic indicate that chemical derivatization improves chemical stability or storage lifetime, detection sensitivity and specificity, as well as screening coverage for diseases or other clinical applications such as clinical diagnosis and new drug evaluation for disease therapy. The discussion emphasizes the application of chemical derivatization in LC-MS/MS-based clinical studies concerning detection-oriented parameters (coverage, sensitivity, throughput), separation-oriented aspects (specificity), along with metabolite stability and structural integrity, suggesting it has the potential to be established as one of the standard tools for determination of small-molecule analytes in clinical laboratories.