Simultaneous determination of amino acid and monoamine neurotransmitters in serum by high performance liquid chromatography coupled with precolumn derivatization

Using o-phthalaldehyde (OPA) as the derivatization reagent, a precolumn derivatized -high performance liquid chromatography (HPLC) method was developed for the simultaneous determination of amino acid neurotransmitters taurine (Tau), glutamic acid (Glu), glycine(Gly), and γ -aminobutyric acid (γ-GABA), as well as the monoamine neurotransmitter dopamine (DA), in serum samples. The samples and ethanol were mixed at a volume ratio of 1:2 (v/v) for protein precipitation. After centrifugation, the supernatant was withdrawn and blown to dryness using nitrogen. The residue was pre-column derivatized with OPA, and the derivatized product was isolated by gradient elution ona Luna 5u C18 column (250 mm×4.6 mm, 5 μm). Under the optimal experimental conditions, the five neurotransmitters showed good linearities (r2 ≥ 0.9866). The limits of detection were between 0.10 and 0.40 μmol/L. The spiked recoveries at different spiked levels were 87.57%-115.31%, and the RSDs were below 7.80%. This method is simple, sensitive, and it can be promised for the simultaneous detection of amino acid and monoamine neurotransmitters.