Study On The Determination Of Amino Acids And Amines In Complex Matrix By Halogen Isotope Labeling Mass Spectrometry

The analysis of amino acids and amines mostly uses derivatization techniques to change the properties of the analytes.However,the derivatization reagents that have been reported at this stage are limited in their application scope due to low data accuracy,high price,susceptibility to complex matrix interference of derivative product mass spectrometry signals,and difficulty in data processing.In response to this problem,this paper screened 4 new derivatization reagents,studied the halogen isotope peaks and anti-matrix interference capabilities of their derivatives,and used Python to improve the data processing process.Firstly,the derivatization reaction of the derivatization reagent(4-chlorobenzenesulfonyl chloride)containing the halogen isotope Cl(4-chlorobenzenesulfonyl chloride)with glycine was used as a model to explore the reaction conditions.The optimal derivatization conditions were determined by comparing the reactant feed ratio,the order of reactant feed,the derivatization reaction time,the derivatization temperature,the alkaline environment,and the addition of terminator.The derived product thus obtained is stable and does not need to be purified.The most important thing is that the isotope peaks of halogen Cl can be clearly seen in the chromatogram and mass spectrum of the derivative product,which facilitates rapid qualitative analysis of specific target compounds without fluorescence or ultraviolet absorption in complex matrices.Secondly,the data processing part is not easy to complete due to the complex data matrix of the actual sample and the time-consuming processing process.On this basis,a method for analyzing UPLC-Q-TOF data based on Python scripts was proposed.Four new halogen isotope derivatization reagents(4-chlorobenzenesulfonyl chloride,3,5-dichlorobenzenesulfonyl chloride,4-Bromobenzenesulfonyl chloride,4-bromo-2-chlorobenzenesulfonyl chloride)derivative products of the mass spectrum found the isotopes containing one Cl element,two Cl elements,one Br element,one Cl element and one Br element derivative products peak.This method greatly improves the efficiency of data acquisition and saves time and cost.The experimental results prove the effectiveness and superiority of screening data,and lay a solid foundation for the analysis of mass spectrometry data of actual samples.Finally,because the complex matrix in the actual samples of healthy human urine and milk samples interferes with the detection and analysis of amino acids and amines,this paper establishes a halogen isotope labeling-mass spectrometry technique for the determination of amino acids and amines in complex matrices Research.It was found that when healthy human urine was extracted with water,methanol and acetonitrile,acetonitrile had the best effect.After derivatization,urea,tyrosine,and uric acid were found in urine samples.Commercial milk first uses methanol(the ratio of solvent to milk is 3:1)to precipitate proteins,and then removes lipids by DCM.After derivatization and data processing,there is no isotope peak.It can be inferred that this kind of milk sample is not added Non-protein nitrogen,but the isotope peak of the derivative was detected in the milk sample artificially added with melamine.