果汁中克菌丹农药残留吸收光谱检测

Detection of Captan Pesticide Residue Absorption Spectrum in Fruit Juice

利用紫外可见分光光度计分别获取克菌丹农药和苹果汁–克菌丹农药混合溶液的吸收光谱,发现克菌丹农药及其与苹果汁混合溶液在279 nm处有明显的特征肩峰。对苹果汁–克菌丹农药的特征肩峰的吸光度与克菌丹农药的浓度进行偏最小二乘法线性拟合,建立了吸光度与药液浓度之间的预测模型函数,其相关系数为0.9907,平均回收率为99.6%,LOD (检出限)为0.0360 mg/mL,LOQ (定量限)为1.1999 mg/mL。对苹果汁–克菌丹农药的吸收光谱进行导数运算处理,得到混合药液的导数吸收光谱。与原混合溶液的吸收光谱相比较,苹果汁–克菌丹农药的导数光谱在297 nm处有明显的特征峰。拟合混合药液的浓度与导数光谱吸光度的函数关系,相关系数为0.9934,平均回收率为98.2%,LOD (检出限)为0.0098 mg/mL,LOQ (定量限)为0.0328 mg/mL。结果表明,采用吸收光谱法对苹果汁中的克菌丹农药残留进行直接检测与分析是快速和有效的,而基于导数吸收光谱的检测效果则更优。

The absorption spectra of Captan pesticide and apple juice-captan pesticide mixed solution were obtained by UV-visible spectrophotometer respectively. It was found that Captan pesticide and its mixed solution with apple juice had obvious characteristic shoulders at 279 nm. Partial least squares linear fitting was carried on the absorbance of the characteristic shoulder peaks of apple juice-captan pesticides and the concentration of captan pesticides, and a prediction model function was established between the absorbance and the concentration of the pesticide solution, the cor-relation coefficient (R) was 0.9907, the mean recovery (%) was 99.6%, LOD was 0.0360 mg/mL, LOQ was 1.1999 mg/mL. Derivative processing was performed on the absorption spectrum of the apple juice-captan pesticide to obtain the derivative absorption spectrum of the mixed solution. Compared with the absorption spectrum of the original mixed solution, the derivative spectrum of the apple juice-captan pesticide had an obvious characteristic peak at 297 nm. Fitting the relation-ship between the concentration of the mixed solution and the absorbance of the derivative spec-trum, the correlation coefficient (R) was 0.9934, the mean recovery (%) was 98.2%, LOD was 0.0098 mg/mL, LOQ was 0.0328 mg/mL. The results show that the direct detection and analysis of captan pesticide residues in apple juice by absorption spectroscopy was fast and effective, while the detection effect based on derivative absorption spectroscopy was better.