Simultaneous analysis of D- and L-serine in cerebrospinal fluid by use of HPLC

Abstract

Background: D-Serine is a coagonist for the glycine-binding site of the N-methyl-D-aspartate receptors and has been implicated in various neuropsychiatric functions such as learning, memory, and nociception, as well as schizophrenia and Alzheimer disease. We developed an HPLC method for D- and L-serine in cerebrospinal fluid (CSF). Methods: The dabsylated racemic serine peak, automatically collected using a previously reported HPLC separation process for CSF amino acids, was desalted and subjected to a chiral resolution HPLC step with a Sumichiral column using an ultraviolet-visible detector. Results: The limits of quantification (signal-to-noise ratio = 10) for D- and L-serine were 0.8 and 1.3 μmol/L, respectively. The mean imprecision values (CVs) for within-day measurements of D- and L-serine were 2.1% and 1.8%, respectively, and for between-day were 6.2% and 6.6%. Mean recovery of CSF serine (sum of D-serine + L-serine) applied to the Sumichiral column was 87%. The mean (SD) D-serine concentrations in 45 CSF samples obtained from 16 patients with chronic pain due to degenerative osteoarthritis of the knees, 16 with post-herpetic neuralgia, and 13 with no pain were, respectively, 3.97 (0.44), 1.85 (0.21), and 2.72 (0.32) μmol/L. Conclusion: D- and L-serine can be quantified with ultraviolet-visible detection of dabsyl derivatives. The dabsyl derivatives are stable and allow duplicate analysis of CSF samples in multisample runs. © 2007 American Association for Clinical Chemistry.