| Tyrosine is an aromatic amino acid which comes from the phenylalanine hydroxylation.It plays an important role in the body metabolism and is also an important parameter in the human health.Studies have shown that the disorders of tyrosine metabolic are not only associated with amino acid metabolic diseases,but also a certain degree of correlation with malignant tumors.Therefore,developing a simple,rapid and sensitive analytical method for monitoring of tyrosine and its metabolites in human urine will have a great practical significance for the screening,early diagnosis,monitoring and prognosis of some diseases.However,the studies of tyrosine metabolites mainly focused on the serum samples,but the analysis of tyrosine metabolites in urine samples were less reported.Urine is viewed as the ultrafiltrate of plasma,and the changes of urinary materials may relate to some diseases.Based on published researches,this paper established new methods for the study of tyrosine and its metabolites,and achieved satisfactory results.The main research results are as follows:1. A new method for the simultaneous determination of 4-hydroxyphenyl lactic acid,3-4-hydroxyphenyl propionic acid and 2-5-hydroxyphenyl acetic acid in human urine by gas chromatography-tandem mass spectrometry was established.The separation of 4-hydroxyphenyl acetic acid,4-hydroxyphenyl lactic acid and2-5-hydroxyphenyl acetic acid was carried on a HP-5MS capillary column?30m?0.25 mm?0.25?m?at 1.0 m L/min.Under the optimized chromatographic temperature program to separate,the linear of 4-hydroxyphenyl acetic acid,4-hydroxyphenyl lactic acid and 2-5-hydroxyphenyl acetic acid were all 0.0253.00mg/L.And the recoveries of them were in the range of 94.5%110.0%,with relative standard derivations?RSDs?less than 3.0%.This method was successfully applied to the determination of 4-hydroxyphenyl acetic acid,4-hydroxyphenyl lactic acid and 2-5-hydroxyphenyl acetic acid in human urine.2.A simple and reliable method was established for simultaneous determination of 4-hydroxyphenyl acetic acid,4-hydroxyphenyl lactic acid and 3-4-hydroxyphenyl propionic acid in human urine by high performance liquid chromatography–fluorescence detection.And the separation of three analytes was achieved using a C18 column and a mobile phase formed by 95:5?V/V?mixture of 50 mmol/L ammonium acetate buffer at p H 6.8 containning 5 mmol/L tetrabutyl ammo nium bromide and acetonitrile.Under the optimized conditions,the linear ranges of4-hydroxyphenyl acetic acid,4-hydroxyphenyl lactic acid and 3-4-hydroxyphenyl propionic acid were 0.0550 mg/L?0.054.0 mg/L and 0.14.0 mg/L,and the limits of detection for them were 4.8?10-3 mg/L,8.8?10-3 mg/L and 9.0?10-3 mg/L,respectively.Recoveries of them in urine were in the range of 85.0%120.0%,with relative standard derivations?RSDs?of 1.2%3.1%.This method was successfully used for the simultaneous determination of these three amino acids in the urine.3.A new method was established for the simultaneous determination of Tyrosine,4-hydroxyphenyl acetic acid,4-hydroxyphenyl lactic acid,3-4-hydroxyphenyl propionic acid,4-hydroxyphenethyl amine,3-4-hydroxyphenyl alanine and2-5-hydroxyphenyl acetic acid by ultra-performance liquid chromatography tandem mass spectrometry?UPLC-MS/MS?.Urine was diluted twice with ultra-pure water and centrifuged,and then the supernatant was injected directly.The separation of tyrosine and its metabolites were achieved on a Shim-pack GIST C18 column?75mm?2.1 mm,2mm?.The eluent that 95:5?V/V?20 m M ammonium acetate buffer at p H 5.7 and acetonitrile was delivered to the column at a flow-rate of 0.2 ml/min.Under the optimized conditions,the calibration cures of tyrosine and its metabolites were linear?correlation coefficients?29?0.9992?,and the limits of detection?LOD?and limits of quantification?LOQ?for tyrosine and its metabolites were in the range of0.0030.081 mg/L and 0.0100.270 mg/L,respectively.And the recoveries were in the range of 85.5%112.0%,with RSDs of 1.0%5.0%.This method is simple and rapid,which provided an important methodological reference for the future investigation of tyrosine and its metabolites. |
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