Concentration of 4-methoxy-2-methyl-2-butanethiol in Spanish virgin olive oils

The sensitivity of a stable isotope dilution assay for 4-methoxy-2-methyl-2 -butanethiol (MMB) causing the blackcurrant-like odour in olive oils was im proved. After spiking the oil sample with labelled MMB, the thiols were sep arated from the volatile fraction with an immobilized reagent for thiols. M MB and its standard were purified by multi-dimensional gas chromatography o f the thiol fraction and determined by mass spectrometry. The new procedure was applied to three Spanish oils differing in the intensity of their blac kcurrant-like odour note. The concentrations of MMB lay between 0.4 mu gkg( -1) and 4.3 mu gkg(-1). (C) 1998 Elsevier Science Ltd. All rights reserved.