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建立了在番茄及土壤中乙烯利的顶空-气相色谱检测方法,并研究了其在番茄和土壤中的消解动态及最终残留。利用乙烯利在碱性水溶液中受热并快速分解成乙烯的特点,结合气相色谱-氢火焰离子化检测器(GC-FID)检测。结果表明,在0.025,0.05和2.0 mg/kg三个添加水平下,乙烯利在番茄和土壤中的平均回收率在93.0%~109.1%之间,相对标准偏差(RSD)为0.7%~5.0%。乙烯利在三地番茄及土壤中的消解半衰期分别为5.9~8.2 d和1.3~4.5 d,表明乙烯利消解速率较快;采用85%乙烯利可溶性粉剂,分别按低剂量1 700倍稀释液和高剂量1 133倍稀释液于番茄果实生长至1/3时各施药1次,在收获期时乙烯利在番茄中残留量的最大值为0.682 mg/kg,低于我国制定的乙烯利在番茄中的最大残留限量标准(2 mg/kg)。
The headspace-gas chromatography (GC-MS) method for the determination of ethephon in tomato and soil was established and its digestion dynamics and final residues in tomato and soil were studied. The use of ethephon in aqueous alkaline solution and quickly decomposed into ethylene, combined with gas chromatography - flame ionization detector (GC-FID) detection. The results showed that the average recoveries of ethephon in tomato and soil ranged from 93.0% to 109.1% under three levels of 0.025, 0.05 and 2.0 mg / kg with relative standard deviations (RSDs) of 0.7% -5.0% . The half-lives of ethephon in tomato and soil were 5.9 ~ 8.2 d and 1.3 ~ 4.5 d respectively, indicating that the rate of ethephon digestion was fast. The ethephon 85% High-dose 1 133-fold dilution of tomato fruit growth to 1/3 and 1 each application, during the harvest of ethephon in tomato maximum value of 0.682 mg / kg, lower than the ethephon in China Maximum residue limit in tomatoes (2 mg / kg).