Simultaneous quantification of ephedrines in urine by high-performance liquid chromatography

Merwe, P. J. van der; Brown, Leslie; Hendrikz, S.E.

doi:10.1016/0378-4347(94)00360-2

Cited by 23 publications

(17 citation statements)

References 9 publications

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“…4 shows chromatograms of blank urine and pseudoephedrine extracted from urine. As already mentioned by van der Merwe et al [72], loss of pseudoephedrine during the evaporation step was also observed in our laboratory. Direct injection of the eluents onto the LC-MS/MS system solved this problem.…”

Section: Direct Injection Of Reversed-phase Spe Extracts Onto Silica supporting

confidence: 73%

Bioanalytical liquid chromatography tandem mass spectrometry methods on underivatized silica columns with aqueous/organic mobile phases

Weng

2003

Journal of Chromatography B

251

134

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Section: Direct Injection Of Reversed-phase Spe Extracts Onto Silica supporting

confidence: 73%

Bioanalytical liquid chromatography tandem mass spectrometry methods on underivatized silica columns with aqueous/organic mobile phases

Weng

2003

Journal of Chromatography B

251

134

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“…Further fragmentation of the ephedrines could be partially explained by the availability of the deuterated IS (EP-d 3 ). The loss of the amine moiety (ammonia for NEP and NPEP, CH 3 NH 2 for EP and PEP, (CH 3 ) 2 NH for MEP and CD 3 NH 2 for EP-d 3 ) from the dehydrated precursor molecule could be assigned to the product ion m/z 117.…”

Section: Mass Spectrometrymentioning

confidence: 98%

“…For NPEP a threshold of 5 g/mL and for EP and MEP a threshold of 10 g/mL is applied. In anti-doping analysis ephedrines used to be quantified in urine by GC-NPD, GC-MS or HPLC-UV after preconcentrating the sample by liquid-liquid extraction (LLE) [3][4][5] or after an online clean-up [6]. The sensitivity of liquid chromatography coupled to mass spectrometry (LC-MS) and the compatibility of the system with the aqueous matrix of urine has allowed quantitative analysis of ephedrines without preconcentration step by direct injection [7,8].…”

Section: Introductionmentioning

confidence: 99%

Development and validation of an LC–MS/MS method for the quantification of ephedrines in urine

Deventer

Pozo

Eenoo

et al. 2009

Journal of Chromatography B

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“…The ephedrines 8 and caffeine 2 in the samples were extracted and quantified according to standard laboratory procedures.…”

Section: Methodsmentioning

confidence: 99%

Inadvertent doping through nutritional supplements is a reality

Merwe¹,

Grobbelaar²

2004

S Afr J SM

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Objective. Inadvertent doping through the use of nutritional supplements is a potentially important cause of the increase in positive drug tests involving high-profile Olympic athletes. The aim of this study was to screen over-the-counter nutritional supplements for the presence of steroid or stimulant compounds banned by the International Olympic Committee (IOC) and the World Anti-Doping Agency (WADA).Method. Thirty different nutritional supplements from 14 different manufacturers were bought at shops in Bloemfontein, South Africa and analysed for testosterone and nandrolone prohormones, various ephedrines and caffeine.Results. Eighteen (60%) of the 30 supplements contained no prohibited substances. Of the 12 (40%) positive supplements, 8 (66.7%) contained prohormones and 4 (33.3%) contained stimulants. Six supplements contained prohormones, which were listed on the labels, while 2 contained prohormones not listed on the labels. The stimulants were listed on the labels as Ma Huang, Guarana and Kola extracts and all contained a mixture of ephedrines and caffeine. Conclusion.The results showed that approximately 7% of supplements tested may be mislabelled or contaminated with banned substances and that inadvertent doping through nutritional supplement use is a reality for athletes. The sporting community should therefore be aware that supplements might contain anabolic androgenic steroids and stimulants that are not declared on the labels.

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Simultaneous quantification of ephedrines in urine by high-performance liquid chromatography

Cited by 23 publications

References 9 publications

Bioanalytical liquid chromatography tandem mass spectrometry methods on underivatized silica columns with aqueous/organic mobile phases

Bioanalytical liquid chromatography tandem mass spectrometry methods on underivatized silica columns with aqueous/organic mobile phases

Development and validation of an LC–MS/MS method for the quantification of ephedrines in urine

Inadvertent doping through nutritional supplements is a reality

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