| 1. |
- Xu, Shu-ling, et al.
(författare)
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Double Derivatization Strategy for High-Sensitivity and High-Coverage Localization of Double Bonds in Free Fatty Acids by Mass Spectrometry
- 2020
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 92:9, s. 6446-6455
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Tidskriftsartikel (refereegranskat)abstract
- Free fatty acids (FFAs) are key intermediates of lipid metabolism that have a crucial role in many critical biological processes. The specific locations of carbon-carbon double bonds (C=C) in FFAs are often associated with distinct biological functions. Despite the rapid development of analytical techniques, identification of C=C locations in FFAs with more than three C=C bonds in complex biological matrices remains a challenge. Herein, we describe a double derivatization strategy, coupled with shotgun-mass spectrometry (MS), for unambiguous and sensitive determination of a high-coverage C=C bond (from 1 to 6) locations of FFAs. Our approach is based on combination of acetone labeling of C=C bonds and N,N-diethyl-1,2-ethanediamine (DEEA) labeling of carboxyl groups within FFAs. Acetone labeling of C=C bonds via photochemical reaction provides diagnostic ions, specific to C=C locations, and DEEA labeling of carboxyl groups significantly enhances MS response of diagnostic ions, by invoking a readily protonated tertiary amine group on FFA analytes. By exploiting this double derivatization strategy, the assignment of C=C locations of FFAs with more than three C=C bonds was achieved with high sensitivity (limit of quantitation (LOQ) 0.1-1.5 nmol/L). In contrast, such assignments were not possible by acetone labeling alone, because of the low sensitivity of diagnostic ions in negative ionization mode of MS. The applicability of our method was demonstrated by profiling of FFAs, including unsaturated FFA C=C positional isomers, in liver samples from mice with nonalcoholic fatty liver disease (NAFLD) and their lean controls. The study showed that the high-specificity and high-sensitivity method developed here is promising for accurate identification and quantitation of a wide array of FFAs in biological samples.
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| 2. |
- Yu, Jun-Chao, et al.
(författare)
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Levels and distribution of short chain chlorinated paraffins in seafood from Dalian, China
- 2014
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Ingår i: Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]. - Beijing : Ke xue zhu ban she. - 0250-3301. ; 35:5, s. 1955-1961
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Tidskriftsartikel (refereegranskat)abstract
- Seafood samples were collected from Dalian, China to study the accumulation and distribution characteristics of short chain chlorinated paraffins (SCCPs) by GC/ECNI-LRMS. Sum of SCCPs (dry weight) were in the range of 77-8 250 ng.g-1, with the lowest value in Scapharca subcrenata and highest concentration in Neptunea cumingi. The concentrations of sum of SCCPs (dry weight) in fish, shrimp/crab and shellfish were in the ranges of 100-3 510, 394-5 440, and 77-8 250 ng.g-1 , respectively. Overall, the C10 and C11 homologues were the most predominant carbon groups of SCCPs in seafood from this area,and a relatively higher proportion of C12-13 was observed in seafood with higher concentrations of sum of SCCPs . With regard to chlorine content, Cl1,, CI8 and CI6 were the major groups. Significant correlations were found among concentrations of different SCCP homologues (except C1, vs. Cl10 ) , which indicated that they might share the same sources and/or have similar accumulation, migration and transformation processes.
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