Detection of glutathione, cysteine, and homocysteine by online derivatization‐based electrospray mass spectrometry

Abstract

Rationale Electrospray ionization mass spectrometry (ESI‐MS) is one of the most popular techniques for obtaining structural information, which is commonly used in bioanalysis and clinical diagnostics. However, for the detection of complicated samples with high reactivities (such as reactive sulfur species, RSS), traditional ESI‐MS usually suffers from overlapped and inaccurate signals. In this study, based on the multiphase flow of extractive electrospray ionization (MF‐EESI), an ambient MS technique of online derivatization was proposed to detect thiols without any other sample pretreatment. Methods RSS molecules and the derivatization reagent of 4‐chloro‐7‐nitro‐1,2,3‐benzoxadiazole (NBD‐Cl) were introduced into the internal and innermost capillary of the MF‐EESI system, respectively. By a high‐velocity nebulizing stream of N2 gas through an external capillary, both flows of innermost biothiols and internal NBD‐Cl were electrosprayed and mixed for online reactions. Therefore, the fast derivatization of thiols was used to generate stable ionized derivatives for MS detection. Results By evaluating the changes in MS signals before and after the derivatization, the ions of RSS were identified simply and correctly. Without any sample pretreatment, the fast detection of cysteine, homocysteine, and glutathione has been achieved in the complicated samples. Conclusions The present online derivatization‐based MF‐EESI was successfully used for fast, simple, and accurate detection of biothiols. This presented a potential pathway for the fast identification of thiols in complicated samples.

Applications of ambient ionization mass spectrometry in 2022: An annual review

“… 27 Other studies aiming to improve existing techniques have introduced a plasma treatment step to the DESI pipeline to increase ion signal, 186 studied the effects of ion source geometry on the reproducibility of LAESI imaging, 187 incorporated the use of helium as a nebulizing gas into DESI and ESI, 188 and developed a post‐acquisition mass recalibration method to reduce mass drift in DESI analysis. 189 Others have built custom REIMS devices using a soldering iron to improve analysis of poorly conductive samples, 190 incorporated an online derivatization step into multiphase flow EESI for the analysis of reactive sulfur species, 191 and modified the DART source to reduce undesirable oxidation when using nitrogen gas in place of helium. 192 Some researchers have attempted to produce simpler and lower cost versions of AIMS techniques, such as using repurposed americium‐241 from smoke detectors as ion sources 193 and building miniaturized sample nebulizing devices using cheap piezoelectric materials.…”

Association between Micronutrients and Hyperhomocysteinemia: A Case-Control Study in Northeast China

“…Hcy and other nutrients were completed in the clinical laboratory of Shengjing Hospital according to clinical testing standards. Plasma Hcy levels were determined through chemiluminescence using a commercial kit (Jiuqiang Biological Company, Beijing, China) and an automatic chemiluminassay analyzer (Abbott-i16200, Shanghai, China), following the detection methods reported by Yin [33,34]. Plasma Zn, Cu, Ca, P, Mg, and Pb levels were determined using an atomic absorption spectrometer (Jingbohui Biotechnology Company, Beijing, China), following the method by Komarova [35,36].…”

Devoting turbidity measurements via absorptiometry: glutathione determination

“…The accurate measurement of GSH and GSSG in blood and tissues in absolute and ratiometric terms is therefore considered a putative tool in oxidative stress investigations (8). For detecting glutathione, a number of techniques based on fluorescence (17), colorimetric detection (18), mass spectroscopy (19) and Liquid Chromotagraphy (20) have been published.…”