Quantitative determination of endogenous sorbitol and fructose in human nerve tissues by atmospheric‐pressure chemical ionization liquid chromatography/tandem mass spectrometry

Abstract

Attachment of anions to sorbitol and fructose has been shown to enhance sensitivity in both electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI) mass spectrometry. The post-column addition of CHCl3 produced Cl-adducts of sorbitol and fructose but their signals were suppressed due to the elevated background. Different chlorinated compounds and different additive methods were systematically investigated to form more abundant Cl-adduct precursor ions and deprotonated product ions. The major causes of the high background were explored and effective methods were developed to improve the signal-to-noise ratios and reproducibility. The compositions of mobile phase, percentages of organic modifiers (MeCN, MeOH and water), columns, oven temperature, flow rates and different gradients were investigated to separate sorbitol from fructose along with their isomers including glucose, galactose, mannose, sorbose, mannitol, and dulcitol. The optimized separation was achieved on a Luna 5 mu NH2 100A column (150 x 4.6 mm) using a mobile phase containing MeCN with 0.1% of CH2Cl2 and 50% MeOH in water at a flow rate of 800 microL/min and an oven temperature of 40 degrees C using a gradient liquid chromatography (LC) system. Human nerve tissue samples were extracted by protein precipitation followed by mixed-mode solid-phase extraction. The LC/ESI-MS/MS method produced higher peak intensities than LC/APCI-MS/MS. However, there were matrix effects from extracted tissues in LC/ESI-MS/MS but not in LC/APCI-MS/MS. Consequently, APCI proved to be the more effective method of ionization. Then the LC/APCI-MS/MS method was fully validated and successfully applied to analysis of clinical samples. The concentrations of endogenous sorbitol and fructose were determined using calibration curves employing sorbitol-13C6 and fructose-13C6 as surrogate analytes. The method has provided excellent intra- and inter-assay precision and accuracy with linear ranges of 0.2-80 ng/mg for sorbitol and 1-400 ng/mg for fructose in human nerve tissues.

Deuterium effect on ionization and fragmentation patterns of monosaccharides ionized by atmospheric pressure chemical ionization

“…[15][16][17][18][19][20][21][22][23] APCI has been employed to analyze biological materials and has been compared with ESI. [24][25][26][27][28][29][30] Liang and co-workers 24 compared APCI and ESI to determine sorbitol and fructose and reported that APCI was the more effective method. Zhu and Sato 23 analyzed underivatized monosaccharides using ESI and a tandem mass spectrometer and distinguished underivatized isomeric monosaccharides such as glucose, galactose, and mannose by comparing relative ion intensities of the major product ions.…”

“…[9][10][11] Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are the most currently used API sources which have widely contributed to the success of liquid chromatography coupled to mass spectrometry (LC-MS) for the fast analysis of biological materials. [24][25][26][27][28] Analysis of carbohydrates using LC-MS have been performed mainly with ESI. [15][16][17][18][19][20][21][22][23] APCI has been employed to analyze biological materials and has been compared with ESI.…”

Ranirestat has a stronger inhibitory activity on aldose reductase and suppresses inflammatory reactions in high glucose–exposed endothelial cells

“…HUVECs were treated with or without 24.5 mM glucose (high glucose) in the presence or absence of 50 nM, 500 nM ranirestat or 500 nM epalrestat in basal medium-2 with 2% foetal bovine serum, human fibroblast growth factor and heparin for 24 h. Then, according to the method of Liang et al, 11 sorbitol contents were measured by liquid chromatography tandem mass spectrometry, which consisted of an SIL-HTC and LC-10A (Shimadzu Corp., Kyoto, Japan) and the API4000 tandem mass spectrometer (Applied Biosystems/MDX SCIEX, MA, USA) with atmospheric pressure chemical ionization. The column and autosampler temperatures were 35°C and 10°C, respectively.…”

Influence of Alkali Metal Cation Type on Ionization Characteristics of Carbohydrates in ESI-MS

“…[9][10][11] Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are the most currently used as API sources which have widely contributed to the success of liquid chromatography coupled to mass spectrometry (LC/MS) for the fast analysis of biological materials. [24][25][26][27][28] Analysis of carbohydrates using LC/MS have been performed mainly with ESI. [15][16][17][18][19][20][21][22][23] Zhu and Sato 23 analyzed underivatized monosaccharides using ESI and reported a convenient method for distinguishing underivatized isomeric monosaccharides such as glucose, galactose, and mannose.…”