论文部分内容阅读
目的建立冷冻干燥技术-气相色谱法同时测定蔬菜中20种有机磷农药的方法。方法采用冷冻干燥机对样品进行脱水干燥处理,干燥处理过的样品经二氯甲烷提取,浓缩仪浓缩后,进入气相色谱—火焰光度检测器(FPD)进行定性定量检测。结果该方法在0.00、0.25、0.50、1.00、2.00、2.50 mg/L范围内20种有机磷农药线性良好,相关系数r在0.999 0~0.999 5之间,方法检出限在0.002~0.030 mg/kg;在低浓度样品(农药加标浓度为0.5 mg/kg)中相对标准偏差在2.31%~8.41%之间,加标平均回收率在72.8%~92.5%之间;在高浓度样品(农药加标浓度为2.0 mg/kg)中相对标准偏差在2.25%~6.09%之间,加标平均回收率在76.1%~101.0%之间。采用前述实验方法检测的114份蔬菜样品中,共检出农药13份,检出率为11.4%。结论该方法准确可靠、简便,适用于蔬菜中多种有机磷农药的测定。
Objective To establish a method for the simultaneous determination of 20 organophosphorus pesticides in vegetables by freeze-drying technique and gas chromatography. Methods The sample was dehydrated and dried with a freeze-dryer. The dried sample was extracted with methylene chloride. The sample was concentrated and then entered into the gas chromatograph-flame photometric detector (FPD) for qualitative and quantitative detection. Results The method showed good linearity with 20 organophosphorus pesticides in the range of 0.00,0.25,0.50,1.00,2.00 and 2.50 mg / L with the correlation coefficient r between 0.999 0 and 0.999 5. The detection limits were 0.002-0.030 mg / kg. The relative standard deviations (RSDs) were between 2.31% and 8.41% in spiked samples (spiked at a concentration of 0.5 mg / kg) and the spiked average spiked recoveries ranged between 72.8% and 92.5% The relative standard deviations (RSDs) were between 2.25% and 6.09% at a spiked concentration of 2.0 mg / kg and the average recoveries were between 76.1% and 101.0%. Of the 114 vegetable samples tested by the aforementioned experimental method, 13 pesticides were detected, with a detection rate of 11.4%. Conclusion The method is accurate, reliable and simple and is suitable for the determination of many organophosphorus pesticides in vegetables.