Relative Mass Defect Filtering of High-Resolution Mass Spectra for Exploring Minor Selenium Volatiles in Selenium-Enriched Green Onions

Shah, Monika; Meija, Juris; Caruso, Joseph A.

doi:10.1021/ac060703k

Cited by 24 publications

(18 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A slightly more comprehensive version of that plot is shown in Figure , comparing the relative MD of several naturally occurring compound classes as a function of their % hydrogen content. Relative MDF has also been employed for detecting new selenium‐containing volatiles in plants. In this example, a simple relative MD‐based algorithm was used to simplify high resolution EI spectra from a GC‐TOF‐MS instrument.…”

Section: Mass Defect Filteringmentioning

confidence: 99%

The use of mass defect in modern mass spectrometry

2012

View full text Add to dashboard Cite

Mass defect is defined as the difference between a compound's exact mass and its nominal mass. This concept has been increasingly used in mass spectrometry over the years, mainly due to the growing use of high resolution mass spectrometers capable of exact mass measurements in many application areas in analytical and bioanalytical chemistry. This article is meant as an introduction to the different uses of mass defect in applications using modern MS instrumentation. Visualizing complex mass spectra may be simplified with the concept of Kendrick mass by plotting nominal mass as a function of Kendrick mass defect, based on hydrocarbons subunits, as well as slight variations on this theme. Mass defect filtering of complex MS data has been used for selectively detecting compounds of interest, including drugs and their metabolites or endogenous compounds such as peptides and small molecule metabolites. Several strategies have been applied for labeling analytes with reagents containing unique mass defect features, thus shifting molecules into a less noisy area in the mass spectrum, thus increasing their detectability, especially in the area of proteomics. All these concepts will be covered to introduce the interested reader to the plethora of possibilities of mass defect analysis of high resolution mass spectra.

show abstract

Section: Mass Defect Filteringmentioning

confidence: 99%

The use of mass defect in modern mass spectrometry

2012

View full text Add to dashboard Cite

show abstract

“…Due to the low abundance of selenium in some natural and common processed foods [7], a variety of selenium-enriched materials including yeast [23,24], milk [9], broccoli [25,26], garlic [27,28], green onions [29,30], green tea [31,32] and mushrooms [33,34] have been commercialized or proposed as selenium dietary supplements. Baker's yeast (Saccharomyces cerevisiae) is most commonly used for the production of supplements; selenized or 'high selenium yeasts' are prepared by growing yeast in a sodium selenite-enriched medium [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Speciation of selenium dietary supplements; formation of S-(methylseleno)cysteine and other selenium compounds

Amoako

Uden

Tyson

2009

Analytica Chimica Acta

View full text Add to dashboard Cite

a b s t r a c tSpeciation of selenium is of interest because it is both essential and toxic to humans, depending on the species and the amount ingested. Following indications that selenium supplementation could reduce the incidence of some cancers, selenium-enriched yeast and other materials have been commercialized as supplements. Most dramatically however, the SELECT trial that utilized l-selenomethionine as the active supplement was terminated in 2008 and there is much debate regarding both the planning and the results of efficacy studies. Further, since dietary supplements are not regulated as pharmaceuticals, there are concerns about the quality, storage conditions, stability and selenium content in selenium supplements. Enzymatic hydrolysis enabled selenium speciation profiles to be obtained by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and following derivatization gas chromatography with atomic emission detection (GC-AED). Coated fiber solid phase microextraction (SPME) was used to extract volatile selenium species for determination by GC-AED and GC-MS. Similar speciation patterns were observed between yeast-based supplements subject to extended storage and those heated briefly at elevated temperatures. All the yeast-based supplements and one yeast-free supplement formed S-(methylseleno)cysteine on heating. Evidence was obtained in support of the hypotheses that S-(methylseleno)cysteine is formed from a reaction between dimethyldiselenide and cysteine or cystine.

show abstract

“…1). MeSe 2 Me is the most commonly reported organoselenide in selenium accumulating organisms (Kubachka et al, 2007;Meija et al, 2002Meija et al, , 2003Shah et al, 2007;Zhang and Chasteen, 1994). MeSeSMe may arise from disproportionation of MeSe 2 Me and MeS 2 Me (Chasteen, 1993).…”

Section: Chemical Analysis Of Smt and Atps/smt Transformed Tobacco Plmentioning

confidence: 99%

“…3). A dominant feature of the fragmentation of alkylselenides is the loss of the alkyl group as an alkene, such as the loss of C 2 H 4 from an ethyl selenide or C 3 H 6 from a propyl selenide (Kubachka et al, 2007;Meija et al, 2002;Shah et al, 2007). No such fragments were observed (Fig.…”

Section: Chemical Analysis Of Smt and Atps/smt Transformed Tobacco Plmentioning

confidence: 99%

Organoselenides from Nicotiana tabacum genetically modified to accumulate selenium

et al. 2009

View full text Add to dashboard Cite

Relative Mass Defect Filtering of High-Resolution Mass Spectra for Exploring Minor Selenium Volatiles in Selenium-Enriched Green Onions

Cited by 24 publications

References 17 publications

The use of mass defect in modern mass spectrometry

The use of mass defect in modern mass spectrometry

Speciation of selenium dietary supplements; formation of S-(methylseleno)cysteine and other selenium compounds

Organoselenides from Nicotiana tabacum genetically modified to accumulate selenium

Contact Info

Product

Resources

About