title: 2,3,4,5-Tetrakis(3',4'-dihydroxylphenyl)thiophene: a new matrix for the selective analysis of low molecular weight amines and direct determination of creatinine in urine by MALDI-TOF MS.
abstract: Small organic matrixes are still the most commonly used ones in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) because of their advantages of high sensitivity, convenience, and cost-effectiveness. However, due to the matrix interference in the low mass region, the direct analysis of low molecular weight amines in complex surroundings with conventional organic matrixes remains a challenge. Here, a new Brønsted-Lowry acid compound 2,3,4,5-tetrakis(3',4'-dihydroxylphenyl)thiophene (DHPT) was designed, synthesized, and applied as a matrix for analysis of low molecular weight amines by MALDI-TOF MS. DHPT displays good selectivity in the analysis of amines without matrix-related interference and the low picomole/femtomole limit-of-detection was obtained in positive ion mode. With DHPT, the metabolites including creatinine, glycine, alloxan, allantoin, and 3-hydroxyhippuric acid in human urine were directly analyzed by MALDI-TOF MS. The identity of these metabolites was confirmed by tandem mass spectrometry. Furthermore, the urine creatinine was quantitatively determined using isotope-labeled internal standard. This DHPT-assisted LDI MS method provides a general approach for both qualitative and quantitative analysis of low molecular weight amines.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, China.
authors.forename: Suming
authors.initials: S
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Jianing
authors.initials: J
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Hou
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.forename: Jian'an
authors.initials: J
authors.lastname: Liu
authors.forename: Jiyun
authors.initials: J
authors.lastname: Wang
authors.forename: Shaoxiang
authors.initials: S
authors.lastname: Xiong
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Yang
authors.forename: Zongxiu
authors.initials: Z
authors.lastname: Nie
mesh_terms: D000481:Allantoin / Q000652:urine*; D000496:Alloxan / Q000652:urine*; D003404:Creatinine / Q000652:urine*; D005998:Glycine / Q000652:urine*; D006626:Hippurates / Q000652:urine*; D006801:Humans; D007553:Isotope Labeling; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D006626:Hippurates; D013876:Thiophenes; C535238:3-hydroxyhippuric acid; D000481:Allantoin; D000496:Alloxan; D003404:Creatinine; D005998:Glycine