GC Determination of 18 Organochlorine Pesticides and 7 Polychloro-Biphenyls in Rough Rice with Ultrasonic Extraction of Samples

Sample of rough rice was extracted ultrasonically with a mixture of n-hexane and dichloromethane (3+2). The extract obtained was purified on a chromatographic column filled with florisil, and eluted by a mixture of n-hexane and acetone (9+1). 18 organochlorine pesticides (OCPs) and 7 polychlorobiphenyls (PCBs) in rough rice sample were determined by GC. Linear relationships between values of peak area and mass concentration of the 25 compounds were found in the same range of 5.00-200.0 μg·L-1, with detection limits (3S/N) ranged from 0.01 to 0.20 μg·L-1. Using a blank sample as the matrix, recovery was tested by standard addition method, giving values of recovery in the range of 71.8%-102%, RSDs (n=6) found were in the range of 2.2%-11%.