A simple method of sample preparation for analysis of biphenyl residues in citrus fruit peels by gas chromatography.

A simple method of sample preparation for analysis of residues of the fungicide biphenyl in peels of citrus fruits by gas chromatography (GC) is described. The blended peels are macerated after addition of anhydrous sodium sulphate in dichloromethane for 2 h. After filtration the biphenyl is quantified directly without concentration of the solution by GC with a flame ionization detector (FID) or a mass selective detector (MSD) under single ion mass conditions. Due to the simple method of sample preparation and good average recoveries of 98-103% with standard deviations of 1-4% in the concentration range of 1-10 ppm, the method described is reliable for analysis of biphenyl in citrus fruit peels. In order to avoid loss of the relatively volatile biphenyl no evaporation of the extraction solution occurs.