Analytical selenoamino acid studies by chromatography with interfaced atomic mass spectrometry and atomic emission spectral detection

Uden, Peter C.; Bird, Susan Mary; Kotrebai, Mihály; Nolibos, Paula B; Tyson, Julian F.; Block, Eric; Denoyer, E. R.

doi:10.1007/s002160051105

Cited by 77 publications

(77 citation statements)

References 38 publications

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“…1A and B show the on-line HPLC-ICP-MS chromatograms of selenium-enriched yeast and garlic, respectively. The somewhat poorer separation at the beginning of the chromatogram, as compared to our earlier work, using 0.1% TFA in the mobile phase, 6 is due to the change of the column from a Zorbax SB-C8 (4.6 mm 3 15 cm) to a Symmetry Shield RP8 (3.9 mm 3 15 cm). The latter has a polar modifier group between the silica base and the C8 group 14 and the advantages of the modified column will be evident in upcoming publications.…”

Section: Hplc-icp-ms Analysiscontrasting

confidence: 64%

“…The total selenium contents of the samples were 1922 mg g 21 in the yeast and 296 mg g 21 in the garlic. 6,11 The identities of the peaks eluting at 3.08 and 6.21 min in Fig. 1A and at 4.95 min (Fig.…”

Section: Hplc-icp-ms Analysismentioning

confidence: 97%

“…8 On-line ESI-MS identification was reported by Momplasir et al 9 Detailed reference lists of different existing methods for selenium compound separation are available from earlier publications. 6,[10][11][12] The importance of the extraction method employed must also be noted, since the selenium compounds can exist in a free form or are covalently bound in proteins. Thus, by employing simple water extraction, only the free selenium compounds will be detected, thus leading to incomplete differentiation of identified compounds into major and minor categories.…”

Section: Introductionmentioning

confidence: 99%

“…As demonstrated in our earlier work, establishing a selenium mass balance is important. 6 To release the covalently bound selenoamino acids, enzymatic or acidic hydrolysis is necessary. This is especially important for yeast in which selenomethionine was found to be the major component after hydrolysis, but only a minor component after simple hot water extraction.…”

Section: Introductionmentioning

confidence: 99%

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Identification of the principal selenium compounds in selenium-enriched natural sample extracts by ion-pair liquid chromatography with inductively coupled plasma- and electrospray ionization-mass spectrometric detection

Kotrebai¹,

Tyson²,

Uden³

et al. 1999

Anal. Commun.

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109

105

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PC, "Identification of the principal selenium compounds in seleniumenriched natural sample extracts by ion-pair liquid chromatography with inductively coupled plasma-and electrospray ionization-mass spectrometric detection" (1999 Selenium-enriched garlic and yeast sample extracts and digests were analyzed using ion-pair high performance liquid chromatography (HPLC) with on-line inductively coupled plasma-mass spectrometric (ICP-MS) and electrospray ionization-mass spectrometric (ESI-MS) detection. The principal selenium compounds in these samples were identified as selenomethionine, and Se-adenosyl-selenohomocysteine in yeast, and g-glutamyl-Se-methyl-selenocysteine and possibly g-glutamyl-selenomethionine in garlic. The compounds identified account for 85 and 90% of the total selenium content of the yeast and the garlic samples, respectively. On-line HPLC-ESI-MS selected ion chromatograms (SIC) and mass spectra of selenium compounds extracted from selenium enriched samples are presented. Limits of quantification (LOQ, defined as S/N = 10) for HPLC-ICP-MS were in the range 10-50 ng mL 21 Se in the injected extracts. LOQ values for HPLC-ESI-MS were ca. 100 times higher than those of HPLC-ICP-MS.

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Section: Hplc-icp-ms Analysiscontrasting

confidence: 64%

Section: Hplc-icp-ms Analysismentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Identification of the principal selenium compounds in selenium-enriched natural sample extracts by ion-pair liquid chromatography with inductively coupled plasma- and electrospray ionization-mass spectrometric detection

Kotrebai¹,

Tyson²,

Uden³

et al. 1999

Anal. Commun.

Self Cite

109

105

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show abstract

“…The enzymatic and hot water extractions of Se-garlic and Se-yeast followed the procedures Chemistry and Biological Activity of Selenized Plants reported earlier (Uden et al, 1998) and therefore are only briefly summarized here. For the hot water extraction, 5 mL of distilled deionized water was added to 0.2 g of sample in a 15-mL centrifuge tube, and the tube was placed in a doubleboiling water bath for an hour.…”

Section: Methodsmentioning

confidence: 99%

Chemical Speciation Influences Comparative Activity of Selenium-Enriched Garlic and Yeast in Mammary Cancer Prevention

Birringer

Block

et al. 2000

J. Agric. Food Chem.

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268

126

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A recent human intervention trial showed that daily supplementation with selenized yeast (Seyeast) led to a decrease in the overall cancer morbidity and mortality by nearly 50%; past research has also demonstrated that selenized garlic (Se-garlic) is very effective in mammary cancer chemoprevention in the rat model. The goal of this study was to compare certain biological activities of Se-garlic and Se-yeast and to elucidate the differences based on the chemical forms of selenium found in these two natural products. Characterization of organic selenium compounds in yeast (1922 µg/g Se) and garlic (296 µg/g Se) was carried out by high-performance liquid chromatography with inductively coupled plasma mass spectrometry or with electrospray mass spectrometry. Analytical speciation studies showed that the bulk of the selenium in Se-garlic and Se-yeast is in the form of γ-glutamyl-Se-methylselenocysteine (73%) and selenomethionine (85%), respectively. The above methodology has the sensitivity and capability to account for >90% of total selenium. In the rat feeding studies, supplementation of Se-garlic in the diet at different levels consistently caused a lower total tissue selenium accumulation when compared to Se-yeast. On the other hand, Se-garlic was significantly more effective in suppressing the development of premalignant lesions and the formation of adenocarcinomas in the mammary gland of carcinogen-treated rats. Given the present finding on the identity of selenomethionine and γ-glutamyl-Se-methylselenocysteine as the major form of selenium in Se-yeast and Se-garlic, respectively, the metabolism of these two compounds is discussed in an attempt to elucidate how their disposition in tissues might account for the differences in cancer chemopreventive activity.

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Selenium speciation in animal tissues after enzymatic digestion by high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry

et al. 2000

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A procedure is described for the enzymatic digestion of tuna and mussel samples that allows the determination of selenium species by high-performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry. The species were extracted by two-step enzymatic hydrolysis with a non-specific protease (subtilisin). The selenium species were separated on a Spherisorb 5 ODS/AMINO column using two different chromatographic conditions, namely phosphate buffers at pH 2.8 and pH 6.0 as mobile phases. The method determines organic (trimethylselenonium, selenocystine, selenomethionine and selenoethionine) and inorganic selenium species (selenite and selenate), but only organic selenium species were found in the samples. The sum of identified selenium species in the sample was about 30% of the total selenium present in the enzymatic extract despite the fact that recoveries of total hydrolysed selenium were 93-102%. Trimethylselenonium ion and selenomethionine were found in both tuna and mussel samples and an unknown selenium species was also found in tuna samples.

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Analytical selenoamino acid studies by chromatography with interfaced atomic mass spectrometry and atomic emission spectral detection

Cited by 77 publications

References 38 publications

Identification of the principal selenium compounds in selenium-enriched natural sample extracts by ion-pair liquid chromatography with inductively coupled plasma- and electrospray ionization-mass spectrometric detection

Identification of the principal selenium compounds in selenium-enriched natural sample extracts by ion-pair liquid chromatography with inductively coupled plasma- and electrospray ionization-mass spectrometric detection

Chemical Speciation Influences Comparative Activity of Selenium-Enriched Garlic and Yeast in Mammary Cancer Prevention

Selenium speciation in animal tissues after enzymatic digestion by high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry

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