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目的建立龙眼中氯酸盐残留量的检测方法。方法样品匀浆后经纯水超声提取,离心20 min,取上清液经C18小柱净化处理后再经0.45μm滤膜过滤后直接进样检测。以Ion Pac AS19(4 mm)为分析柱,淋洗液自动发生器(EGC)在线产生KOH淋洗液梯度洗脱,抑制电导进行检测,用氯酸盐的峰面积进行定量。结果氯酸盐的检出限(S/N=3)为0.03 mg/L;线性相关系数是0.999 9;样品加标回收率的范围在86.2%~101.3%之间,平均回收率在91.6%~96.9%之间,RSD<5%。市售龙眼中氯酸盐残留量均<0.3 mg/kg。结论该方法具有灵敏度高,操作简单,重现性好,能够快速准确地检测龙眼中氯酸盐残留的浓度,值得推广。
Objective To establish a method for the determination of chlorate residues in longan. Methods After the sample was homogenized, it was extracted by pure water and centrifuged for 20 min. The supernatant was purified by C18 column and filtered through 0.45 μm membrane. Ion Pac AS19 (4 mm) was used as the analytical column. The eluent generator (EGC) was used to generate a KOH eluent gradient. The conductivity was suppressed and the peak area of the chlorate was used for quantification. Results The detection limit (S / N = 3) of chlorate was 0.03 mg / L, the linear correlation coefficient was 0.999 9, the spiked recoveries ranged from 86.2% to 101.3%, and the average recoveries were 91.6% ~ 96.9%, RSD <5%. Longan chlorate residues were <0.3 mg / kg. Conclusion The method has the advantages of high sensitivity, simple operation and good reproducibility. It can quickly and accurately detect the concentration of chlorate residue in longan and is worth popularizing.