Centri-voltammetric determination of glutathione

Centri-voltammetry is a method for concentrating an analyte on an electrode with the aid of a centrifuge. It can be performed in the presence or the absence of a solid carrier/support. This is followed by a voltammetric (analytical) scan. Specifically, we describe here an application of the technique to the determination of glutathione (GSH). Silica gel is used as the carrier precipitate to which gold nanoparticles were added in order to improve accumulation as a result of their strong affinity for thiols. Voltammetry was performed with a carbon paste electrode modified with multi-wall carbon nanotubes. The response to GSH is linear in the 25 and 800 mu M concentration range (the correlation coefficient being 0.9915) and the relative standard deviation is 3.40 % (at 250 mu M of GSH and n=6). The procedure was successfully applied to the determination of GSH in wine and in synthetic plasma using the standard addition method. The recoveries are 100.8 % and 100.0 %, respectively.