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Chlorpyrifos is a Malaysian Pesticide Board-approved organophosphate insecticide, which may become concentrated during fractionation. The objective of this project was to develop and validate a method to detect and quantify chlorpyrifos in food-grade fatty acids ingredients, e.g. caprylic-capric acid mixture and oleic acid (OLA) used to synthesize triacylglyceride based food additives and in the cosmetic industry. A selective ion monitoring gas chromatography–mass spectrometry method with a matrix-matched calibration curve calibration was selected. The method involved the direct injection of chlorpyrifos spiked into the fatty acids matrix. The percentage recoveries at spiking levels of 0.5, 0.75, 2.5, and 4.0 μg g−1 of chlorpyrifos in OLA and caprylic-capric acid ranged from 85.7%–101.1% to 97.2%–112%, respectively, with a relative standard deviation of within 11%. The intra-day and inter-day precision were deemed acceptable as indicated by an relative SD value of within 10%. A good linear relationship with a coefficient of correlation >0.99 for the matrix-matched calibration was achieved between 0.5 and 5 μg g−1. The limit of detection and limit of quantification corresponded to 0.5 μg g−1 for OLA and 0.55 μg g−1 for caprylic-capric acid. 相似文献
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微量农药溶液近红外光谱PLS模型的不同预处理方法对比研究 总被引:1,自引:0,他引:1
比较了常用的多种预处理方法对近红外光谱技术(NIR)检测微量农药溶液含量的影响,使用偏最小二乘法(PLS)分别对各预处理方法处理后的数据建立了数学模型,利用两种不同农药初步探讨了数据量对PLS建模结果的影响。结果表明:矢量归一化(SNV)对26个微量毒死蜱溶液样本的预处理效果综合参数最好,校正集参数为R=0.9957,RMSECV=0.182,预测集参数为R=0.9992,RMSEP=0.0802;减去一条趋势线对20个微量炔螨特溶液样本的预处理效果综合参数最好,校正集参数为R=0.9925,RMSECV=0.649,预测集参数为R=0.9952,RMSEP=0.646。26个样本的微量毒死蜱溶液PLS建模结果优于20个样本的微量炔螨特溶液。 相似文献
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目的探讨毒死蜱在茶园的使用安全性。方法采用室内检测和田间试验方法,对45%毒死蜱乳油在茶叶上的残留消解动态进行研究。样品采用含体积分数1%乙酸的乙腈溶液超声提取,分散固相萃取净化,气相色谱电子捕获法测定。结果在0.005~2.0 mg/L范围内,毒死蜱的质量浓度与其峰面积呈良好的线性关系,相关系数大于0.9990;添加浓度为0.01、0.2和1 mg/kg时,毒死蜱在茶叶中的平均回收率为81.7%~110.7%,RSD小于10%,检出限、定量限分别为0.003 mg/kg、0.01 mg/kg。施药剂量为有效成分540~1080 g/hm2时,毒死蜱在茶叶上的残留量与施药剂量密切相关,施药后初期残留量迅速降低,而后平缓下降,消解动态符合一级动力学反应模型,半衰期为3.78 d~4.16 d,施药后21 d,残留量小于0.1 mg/kg。结论毒死蜱为适于在茶园使用的农药品种,参照欧盟茶叶上毒死蜱的最大残留限量标准(MRL),45%毒死蜱乳油按常规方法喷雾,制剂有效成分用量不超过1080 g/hm2,施药1次,安全间隔期大于21 d,在茶叶上的残留是安全的。但由于毒死蜱在茶树上尚未登记,因此不建议在茶园中使用。 相似文献
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Anandrao R. Kulkarni Kumaresh S. Soppimath Tejraj M. Aminabhavi Ashok M. Dave 《应用聚合物科学杂志》2002,85(5):911-918
Novel polymeric sodium alginate (Na‐Alg) interpenetrating network (IPN) beads have been prepared by crosslinking Na‐Alg blend with gelatin (GE) or egg albumin (EA) using glutaraldehyde (GA) as the crosslinking agent. These beads were used for the controlled release of chlorpyrifos. The swelling experiments were performed in water at different temperatures, and these data were used to calculate the molecular mass (MC) between crosslinks as well as diffusion coefficients. Diffusion coefficients calculated from desorption data were lower by about two orders of magnitude than those calculated from sorption results. Higher values of MC were obtained for the gelatin‐based IPNs than the neat Na‐Alg and egg albumin‐based matrices. Size of the beads did not vary significantly either by the network or by increasing the exposure time to the crosslinking agent. The scanning electron microscopy (SEM) was used to understand the surface characteristics of the beads. Differential scanning calorimetry (DSC) indicated a molecular level dispersion of chlorpyrifos in the polymer matrix. The percentage entrapment efficiency showed a dependence on the type of network polymer as well as time of exposure to the crosslinking agent. The encapsulation efficiency decreased with an increase in time of exposure to the crosslinking agent. In vitro release experiments have been performed to follow the release kinetics of chlorpyrifos from the matrices. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 911–918, 2002 相似文献
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