A New Gas Chromatography Method for Quality Control of Methylsulfonylmethane Content in Multicomponent Dietary Supplements
Abstract
This paper reports the first gas chromatography method with flame ionization detection (GC-FID) for rapid assay of the quality control of methylsulfonylmethane (MSM) content in multicomponent dietary supplements. The proposed method was completely validated and used for quality control of multicomponent dietary supplements available in the local market.
The study showed that the content of MSM varied in different commercial samples (77.7-112.3 % of the declared amount) and was dependent on different qualities of the dietary supplement producer. The developed method was based on the rapid extraction of MSM into acetone using ultrasound bath (5 min) and on the subsequent quantification of the MSM by gas chromatography.
The used GC conditions were as follows: fused silica cyanopropylphenylmethylpolysiloxane capillary column Alltech AT(TM-624) (30 m x 0.32 mm i.d., 1.8-mu m film thickness), injection mode split of 1:10, sample volume of 1.0 mu L, injector temperature of 190 A degrees C, detector temperature of 190 A degrees C, column temperature held at 190 A degrees C for whole analysis time, and helium carrier gas flow rate of 0.7 mL min(-1). Nitrobenzene was chosen as internal standard for precise and accurate quantification of MSM in dietary supplements.
Method precision evaluated as relative standard deviation was 1.7 %, and method accuracy evaluated as recovery was in the range of 102.5-106.2 %. The method required no special sample pretreatment, so it showed to be simple, robust, rapid (short analysis time of less than 4 min), and suitable for routine analysis of MSM in food quality control laboratories.