Determination of Tyramine in Hair Samples by GC-MS

A simple and sensitive method for the determination of tyramine in hair as N-heptafluorobutyryl derivative by gas chromatography-mass spectrometry has been developed. After digestion of the hair with aqueous NaOH, the aimed the analytes were extracted with solid-phase extraction on diatomaceous earth columns, followed by derivatization with heptafluorobutyryl chloride and elution with n-hexane: propyl acetate (30:1, v/v) simultaneously. The method was linear (r (2) = 0.9982) in the concentration range of 0.5-200 pmol mL(-1), reproducible (intra-day precision = 4.4-5.5 %, inter-day precision = 3.3-6.5 %), accurate (recoveries = 96.0-97.9 %) and sensitive (LOD = 0.1 pmol mL(-1)). The method was successfully applied for analyzing the hair tyramine from the control group, the patients with schizophrenia group and the drug abuse group. Compared with the control group, there is a significant difference to the patients with schizophrenia group, while there is no significant difference to the drug abuse group. Additionally, there is no significant difference between the drug abuse group and the patients with schizophrenia group. It is a clue that tyramine could be a biological marker for schizophrenia.