A high‐throughput on‐line microdialysis‐capillary assay for D‐serine

Abstract

A high‐throughput method is described for the analysis of D‐serine and other neurotransmitters in tissue homogenates. Analysis is performed by microdialysis‐capillary electrophoresis (CE) with laser‐induced fluorescence (LIF) detection in a sheath flow detection cell. Sample pretreatment is not required as microdialysis sampling excludes proteins and cell fragments. Primary amines are derivatized on‐line with o‐phthaldialdehyde (OPA) in the presence of β‐mercaptoethanol followed by on‐line CE‐LIF analysis. Under the separation conditions described here, D‐serine is resolved from L‐serine and other primary amines commonly found in biological samples. Each separation requires less than 22 s. Eliminating the need for sample pretreatment and performing the high‐speed CE analysis on‐line significantly reduces the time required for D‐serine analysis when compared with traditional methods. This method has been used to quantify D‐serine levels in larval tiger salamander retinal homogenates, as well as dopamine, γ‐amino‐n‐butyric acid (GABA), glutamate and L‐aspartate. D‐serine release from an intact retina was also detected.