김윤지 (한국화학연구원)

조성희 (한국화학연구원)

김윤지 (한국화학연구원)

이장재 (한국화학연구원)

김정권 (충남대학교)

조성희 (한국화학연구원)

 Neurochemicals orchestrate complex brain functions and facilitate intercellular communication in the nervous system. Their imbalance is implicated not only in neurological disorders such as Alzheimer's and Parkinson's disease but also impacts systemic health, affecting cardiovascular, gastrointestinal, and other physiological processes. Precise quantification of these molecules is critical for elucidating disease mechanisms and developing targeted therapies. However, traditional analytical approaches have struggled to provide comprehensive neurochemical profiles due to the diverse polarity and structural similarities of these compounds.

Our research introduces an innovative liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique for the simultaneous analysis of 55 neurochemicals without the need for derivatization. This method employs a strategic combination of electrospray ionization (ESI) and multiple reaction monitoring (MRM) to enhance the detection of polar compounds, particularly amino acids. We utilized a fluoro-phenyl column, which demonstrated superior resolution for aromatic monoamines. To minimize analyte loss, we refined the sample preparation process, opting for a protein precipitation technique over conventional extraction methods. Furthermore, we meticulously optimized the mobile phase composition and column temperature to achieve maximum sensitivity in neurochemical detection.

 Our validated method exhibited robust performance metrics: excellent linearity (r² > 0.990), quantitation limits spanning 0.5 to 250 ng/mL, and detection limits ranging from 0.15 to 75 ng/mL. Rigorous validation adhering to AOAC guidelines confirmed the method's reliability, with intra-day accuracy of 75.4-119% and precision of 0.451-29.7%, alongside inter-day accuracy of 77.9-118% and precision of 0.349-23.5%. This analytical platform offers a powerful tool for accurate and sensitive quantification of diverse neurochemicals in biological matrices. Its capacity for comprehensive neurochemical profiling opens new avenues for identifying pathway-level biomarkers in neurological disorders, transcending the limitations of single-biomarker paradigms.