Cooperative trial studies on the analysis of ethyl carbamate using capillary gas chromatography

Abstract

AbstractA design for cooperative study of analytical methods is described which involves the analysis of spiked samples and evaluation of the results using a linear regression technique. Two examples are described involving the study of ethyl carbamate in whisky at levels from 40–170 μg/L and in beer at levels <1–20 μg/L. Most participating laboratories used capillary gas chromatography with variations in sample preparation and detection methods. Acceptability criteria were defined as: intercept ±2 standard deviations of the group mean, slope 0.9 to 1.1, individual analyses of duplicates within ±10% of the mean and correlation coefficient better than 0.99. In the whisky trial, four of the seven laboratories taking part met these criteria, while for the beer trial all of the laboratories taking part were sufficiently close to these standards to be considered satisfactory given that the analyses were being performed close to the detection limit of the methods.