Head-space Gas Chromatographic Determination of Benzene Homologues in Paint and Adhesive

Benzene homologues (benzene,toluene and xylene were tested in special) in paint and adhesive were determined by gas chromatography. Fifty μL of the gaseous analyte were taken from the top of the head-space sample bottle,in which an appropriate amount of the sample was added together with pure water to have the volume ratio of gas to liquid phase achieved to 2 to 1,and equilibrated statically at 70 ℃ for 20 min under hermetic condition,and were introduced into the GC instrument. Linear relationships between values of peak area and mass concentration of benzene,toluene or xylene were kept in the range from 100 to 1 000 mg·L-1. Detection limits (3S/N) for the 3 compounds found were 0.074,0.106 and 1.292 mg·L-1 respectively. Recovery and precision of the method were tested by analyzing a known paint sample with addition of mixed standard solution at 3 different concentration levels,and determining each for 5 replications,values of average recovery obtained were in the range of 99.3%-101.7%,and values of RSD′s (n=5) in the range from 1.6% to 4.7%.