Development of microwave‐assisted derivatization followed by gas chromatography/mass spectrometry for fast determination of amino acids in neonatal blood samples

Analysis of amino acids in blood samples is an important tool for the diagnosis of neonatal amino acid metabolism disorders. In the work, a novel, rapid and sensitive method was developed for the determination of amino acids in neonatal blood samples, which was based on microwave-assisted silylation followed by gas chromatography/mass spectrometry (GC/MS). The amino acids were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) under microwave irradiation. The controlled reaction was carried out employing BSTFA under conventional heating at 120 degrees C for 30 min. Experimental results show that microwave irradiation can accelerate the derivatization reaction of amino acids with BSFTA, and much shorten analysis time. The method validations (linear range, detection limit, precision and recovery) were studied. Finally, the method was tested by determination of amino acids in neonatal blood by the measurement of their trimethylsilyl derivatives by GC/MS in electron impact (EI) mode. Two biomarkers of L-phenylalanine and L-tyrosine in phenylketonuria (PKU)-positive blood and control blood were quantitatively analyzed by the proposed method. The results demonstrated that microwave-assisted silylation followed by GC/MS is a rapid, simple and sensitive method for amino acid analysis and is also a potential tool for fast screening of neonatal aminoacidurias.