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建立了简单、快速的鲜烟叶中苦参碱的测定方法。样品用0.01 mol/L的乙酸水溶液(pH3.5)提取,强阳离子交换柱(SCX-SPE)净化,气相色谱-氮化学发光检测器(GC-NCD)测定。通过净化方法比较发现,SCX-SPE法比常规溶剂萃取法具有更好的净化效果。在选定的色谱条件下,苦参碱在0.15～15.0μg/mL范围内,其质量浓度与峰面积之间呈良好的线性关系,决定系数R2=0.999 7。对烟草空白样品进行添加回收试验,在0.05～0.4 mg/kg范围内其回收率在89.5%～91.6%之间,相对标准偏差(RSD)在2.7%～3.6%之间,检测限(LOD)为0.03 mg/kg,能满足苦参碱在烟草样品中的残留检测。田间试验结果表明:苦参碱的消解动态曲线符合一级动力学方程,其在烟草中的半衰期为7.64 d,属易降解农药。
A simple and rapid method for the determination of matrine in fresh tobacco leaves was established. The samples were extracted with 0.01 mol / L acetic acid aqueous solution (pH 3.5), purified by a strong cation exchange column (SCX-SPE) and analyzed by gas chromatography-nitrogen chemiluminescence detector (GC-NCD) By comparison of purification methods, SCX-SPE method has better purification effect than conventional solvent extraction method. In the selected chromatographic conditions, matrine in the range of 0.15 ~ 15.0μg / mL, the mass concentration and peak area showed a good linear relationship, the determination coefficient R2 = 0.999 7. The recoveries of blank samples from tobacco increased from 89.5% to 91.6% and the relative standard deviations (RSDs) were between 2.7% and 3.6% in the range of 0.05-0.4 mg / kg. The limit of detection (LOD) 0.03 mg / kg, which can meet the residual detection of matrine in tobacco samples. Field experiments showed that the kinetic curves of matrine digestion were in accordance with the first-order kinetic equation. The half-life of matrine in tobacco was 7.64 days, which was a biodegradable pesticide.