Spectrophotometric determination of biacetyl in distillates of wine by flow injection

Abstract

The reaction of biacetyl with 1-naphthol and creatine in an alkaline medium has been used to develop a flow injection method for the determination of biacetyl. Acetoin is the principal interferent and, by exploiting the fact that biacetyl reacts comparatively faster than acetoin, the optimum experimental conditions for increasing the selectivity were found. Under these conditions, the relationship between the peak height (absorbance) and the concentration of biacetyl was linear up to a concentration of 10.0 µg cm^–3 with a relative standard deviation (RSD) of 0.74 and 0.37% for 1.0 and 5.0 µg cm^–3 biacetyl standards (n= 10), respectively. The sampling rate was 30 h^–1. When the method was applied to the determination of blacetyl in wine, after a separation step for biacetyl by steam distillation, the RSD ranged from 2.7 to 3.3%, and the results were in good agreement with those obtained by a conventional spectrophotometric method.