Determination of Endogenous Amino Acids and Taurine in Honey by Ultra-performance Liquid Chromatography£­Tandem Mass Spectrometry with AQC Pre-column Derivation

KeyWord:honey  amino acids  taurine  AQC derivation  ultra-performance liquid chromatography£­tandem mass spectrometry

Abstract:

      An ultra-performance liquid chromatography£­tandem mass spectrometry£¨UPLC£­MS/MS£© with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate£¨AQC£© pre-column derivation was established for the determination of 23 endogenous amino acids and taurine in honey£®The honey samples were extracted with water and derived with AQC£¬then separated on an AccQ£­Tag Ultra C18 column£¨2.1 mm ¡Á 100 mm£¬1.7 ¦Ìm£© by gradient elution with acetonitrile£­10 mmol/L ammonium formate as the mobile phase£¬and finally analyzed by mass spectrometry in positive ion multiple reaction monitoring mode and quantified by internal standard method£®The calibration curves for amino acids and taurine showed good linearity in their respective concentration ranges£¬with correlation coefficients£¨r£© not less than 0.993 0£®The limits of detection£¨LODs£© and the limits of quantitation£¨LOQs£© were in the range of 0.03£­0.15 ¦Ìmol/L and 0.1£­0.5 ¦Ìmol/L£¬respectively£®The average recoveries ranged from 90.5% to 109%£¬with relative standard deviations of 1.2%£­4.7%£®Through analyses on 39 batches of real honey£¬39 batches of adulterated honey and 10 batches of syrup£¬it was found that the types and content of target compounds in different honey sources differed largely£®The contents of amino acids and taurine in adulterated honey were significantly lower than that in real honey£¬and no target compounds were detected in syrup£®This method was simple£¬sensitive and accurate£¬and it could be used for the determination of free amino acids and taurine in honey£¬providing a technical support for the quality evaluation and authenticity identification.