Chiral analysis of amino acid neurotransmitters and neuromodulators in mouse brain by CE-LIF

Chiral CE method has been developed for quantitative determination of d‐amino acid modulators of NMDA glutamate receptor; d‐serine and d‐aspartate along with l‐glutamate and l‐aspartate in biological samples. These ligands are suggested to be involved in regulation of NMDA receptor related brain functions, such as neurogenesis, neuronal plasticity, and memory formation. For sensitive determination of the amino acids LIF detection was chosen, and a fluorogenic reagent, 7‐fluoro‐4‐nitro‐2,1,3‐benzoxadiazole was used for derivatization. An amino‐modified β‐CD, 6‐monodeoxy‐6‐mono(3‐hydroxy)propylamino‐β‐CD (HPA‐β‐CD) was applied as chiral selector. Determinations were accomplished in a polyacrylamide coated capillary and reverse polarity was used for the analysis of the negatively charged analytes. The method was optimized and validated; 6 mM HPA‐β‐CD in 50 mM HEPES buffer, pH 7 was appropriate to achieve baseline separation of the analytes. The limit of quantification with acceptable accuracy is 0.05 μM for both d‐amino acids. The method was used for the determination of d‐aspartate and d‐serine content in various brain regions of adult mice.