Flow-through sensor for determination of butylated hydroxytoluene in cosmetics

A flow-through optosensor with solid phase UV spectroscopic detection is proposed for the direct determination of the antioxidant Butilated Hydroxytoluene (BHT) without previous derivatization. The method is based on the transient retention of this compound in a flow-through cell packed with C-18 silica using ethanol: water mixture as a carrier, and its intrinsic absorbance monitored at 274 nm. Afterwards, the recording, of the analytical signal BHT was easily and quickly desorbed from the solid support by the same carrier. The calibration graphs were linear over the range 2.0-300.0 mgL(-1) using area as the analytical parameter. The relative standard deviation (RSD) was between 0.5 and 1.6%. The method was applied to the determination of this antioxidant in several cosmetics samples and was validated using the standard addition methodology and an HPLC reference method.