In vivo quantification of volatile organoselenium compounds released by bacteria exposed to selenium with HS-SPME-GC-MS. Effect of selenite and selenium nanoparticles

• Published in: Talanta (Oxford) Vol. 224; p. 121907
• Main Authors: Moreno-Martin, Gustavo, Sanz-Landaluze, Jon, León-González, María Eugenia, Madrid, Yolanda
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-03-2021
• Subjects: Bacteria metabolisms; Escherichia coli; Gas Chromatography-Mass Spectrometry; In vivo headspace solid-phase microextraction; Nanoparticles; Organoselenium Compounds; Selenious Acid; Selenium; Selenium biotransformation; Selenium nanoparticles; Solid Phase Microextraction; Staphylococcus aureus; Volatile mixed sulfur/selenium compound; Volatile Organic Compounds - analysis; Volatile organoselenium compounds; Volatile mixed sulfur/selenium compound; Bacteria metabolisms; In vivo headspace solid-phase microextraction; Volatile organoselenium compounds; Selenium biotransformation; Selenium nanoparticles
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2020.121907

Quantification of volatile organoselenium species released by Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), after their growth in the presence of 1 and 2 mg Se·L-1 as both selenite and chitosan-modified selenium nanoparticles (Ch-SeNPs), was achieved by the application of a method based on headspace solid-phase microextraction (HS-SPME) and in-fiber internal standardization, combined with gas chromatography coupled to mass spectrometry (GC-MS). This method consisted of an initial extraction of the released volatile organoselenium compounds on the SPME fiber, followed by the extraction of internal standard (IS), deuterated dimethyl sulfide (d6-DMS), on the same fiber before its desorption at the injection port of GC-MS. The results showed that the biotransformation of selenite and Ch-SeNPs into volatile organoselenium compounds was dependent on both the type of bacterial species and the chemical form of selenium (Se) administered. In this sense, E. coli was able to biotransform both selenite and Ch-SeNPs into dimethylselenium (DMSe) and dimethyldiselenium (DMDSe) while S. aureus, biotransformed selenite into DMSe and DMDSe and, Ch-SeNPs only into DMDSe. Additionally, the formation of a volatile mixed sulfur/selenium compound, dimethyl selenenyl sulfide (DMSeS), from Se in nanoparticulated form has been detected for the first time.
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•HS-SPME-GC was applied for in vivo quantification of DMDSe by bacteria.•E. coli and S. aureus biotransform SeNPs into volatile Se and mixed Se/S compounds.•DMSe, DMDSe and DMDSeS were released by E. coli and S. aureus.•DMSe and DMDSe formation depended on the bacterial species and the Se form.