Liquid chromatographic determination of S-adenosyl-L-methionine in dietary supplement tablets.
A simple and reliable liquid chromatographic method was developed for the determination of S-adenosyl-L-methionine (SAM) in dietary supplement tablets. SAM in products was extracted with a phosphate buffer and separated from the mixture on a reversed-phase C8 column by ion-pair chromatography. A gradient mobile phase containing phosphate buffer, sodium octanesulfonate as the ion-pair reagent, and acetonitrile at a flow rate of 1.2 mL/min was used in the analysis. The UV detection wavelength was set at 257 nm. The calibration curve was linear over a range of 75-375 microg/mL for the SAM active ion with R2 = 0.9999. Replicate tests indicated good reproducibility of the method with a relative standard deviation of 0.9% (n = 8). The multiple extractions and recoveries from fortified products showed the high accuracy of the analysis. The use of the acidic buffer for SAM extraction and elution and the use of a fresh standard for each calibration to counteract the instability of the SAM compound significantly improved the accuracy of the method.
NOW Natural Foods, Inc., Methods Development Laboratories, Bloomingdale, IL 60108, USA. jzhou@nowfoods.com
Joseph ZiQi
JZ
Zhou
Ted
T
Waszkuc
Spiro
S
Garbis
Felicia
F
Mohammed
D002623:Chemistry Techniques, Analytical; D002853:Chromatography, Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D015203:Reproducibility of Results; D012436:S-Adenosylmethionine / Q000032:analysis*; D013607:Tablets
D013607:Tablets; D012436:S-Adenosylmethionine