RESUMO
The decomposed products of trichlorfon in gas chromatographic analysis were identified by mass spectrometry (MS). After MS interpretation, three decomposed products, trichloroacetaldehyde, dimethyl phosphite and dichlorvos were identified. The effects of gas chromatographic conditions on decomposed products of trichlorfon, e. g. injection temperature, injection mode and oven ramp, were studied. The experiments showed that all of the factors have effects on decomposed products of trichlorfon, however, the injection temperature is the key factor to cause trichlorfon being decomposed. The higher the injection temperature is, the bigger the amount of trichlorfon being decomposed. When the injection temperature was raised from 150 degrees C to 250 degrees C, the remaining trichlorfon fell from 86% to 20%. Therefore, on-cold column injection mode gas chromatography or high performance liquid chromatography was recommended for exact quantification of trace trichlorfon.