芹菜中苯醚甲环唑农药残留表面增强拉曼光谱的快速检测

采用表面增强拉曼光谱技术结合快速溶剂前处理方法快速分析芹菜中苯醚甲环唑农药残留。利用乙腈提取芹菜汁,采用N-丙基乙二胺(PSA)、C18和石墨化碳去除芹菜汁中的脂肪酸、蜡质、色素和固醇等荧光物质,分别采集不同浓度苯醚甲环唑标准溶液和以芹菜汁为基质的苯醚甲环唑溶液表面增强拉曼信号。结果表明,1192 cm-1特征峰强度与以芹菜汁为基质的苯醚甲环唑溶液浓度在1~10 mg/L范围内具有良好的线性关系,相关系数为0.9622。以芹菜汁为基质的苯醚甲环唑溶液的最低检测浓度1 mg/L。方法的回收率为92.4%~113.2%,相对标准偏差RSD在8.83%~12.4%之间。在对4个未知浓度的样本进行t检验时,参考值与预测值之间无显著差异。该方法操作简单,单个样本检测时间在20 min内完成,基本满足国家规定的残留限量要求,可为蔬菜中农药残留快速检测装置开发奠定基础。

Rapid Detection of Difenoconazole Residues in Celery by Surface-enhanced Raman Spectroscopy

Surface-enhanced Raman spectroscopy (SERS) combined with the fast solvent pretreatment method was used to rapidly detect difenoconazole residues in celery. Celery juice was extracted with acetonitrile, then N-propylethylenediamine, C18, and graphitic carbon were used to remove fluorescent materials in celery juice, such as fatty acids, waxes, pigments, cholesterols. SERS signals corresponding to different concentrations of difenoconazole solutions in celery juice matrix were recorded using a laser Raman spectrometer. The results showed that the intensity of the characteristic peak at 1192 cm-1 and the concentration of difenoconazole between 1 and 10 mg/L in celery juice matrix exhibited a good linear relationship, with a correlation coefficient of 0.9622. The limit of detection by SERS for difenoconazole in celery juice matrix was 1 mg/L and the recovery of the method was in the range of 92.4% to 113.2%. Additionally, the relative standard deviation (RSD) was between 8.83% and 12.4%. t-Tests were performed on four samples with unknown concentrations and the results indicated that there were no significant difference between the reference and predicted values. The operation of this method is simple and the duration for the detection of a single sample was only 20 minutes. Therefore, this method meets the national requirement for the maximum residue limits (MRLs) of difenoconazole in vegetables and the results of this study will help in the development of devices to rapidly detect pesticide residues in vegetables.