Development and validation of a sensitive assay for analysis of D/L-serine in cells using ultra-high performance liquid chromatography-fluorescence detector

The aim of this study was to establish a simple, sensitive, and robust ultra-high performance liquid chromatography coupled with fluorescence detection method (UPLC-FLD) for the determination of chiral D/L-serine in cells. D/L-serine in cells were derivatizated by o-phthalaldehyde (OPA) and N-acetyl-L-cysteine (NAC). Carbocisteine was selected as the internal standard. The derivatives were separated on a C18 column by gradient elution. The excitation and emission wavelengths for fluorescence determination are 340 nm and 450 nm, respectively. The retention time of D-serine and L-serine was 23.3 and 23.9 min respectively, which presented a perfect separation. The accuracy of D-serine and L-serine were ranged from 96.46 % to 109.63 % and 95.50 %-102.20 %, respectively. The precision of D-serine and L-serine were ranged from 4.34 % to 14.56 % and 3.56 %-13.73 %. The limit of quantitation of D-serine and L-serine were 0.1 nmol/mL. The concentration of D/L-serine varies in different cell lines. This method can satisfy the determination of D/L-serine in astrocytes and other cells, which can be used for the study of D/L-serine metabolism and related mechanisms. In short, we have established a simple, stable, reliable and robust method for the determination of D/L-serine in cells. In addition, the D/L-serine levels in different cells were quantified in this study, which can provide a reference for the study of D/L-serine metabolism in cells.