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目的建立适用于分散式固相萃取结合高效液相色谱法测定植物油中苯并(a)芘含量的不确定度分析方法。方法样品用正己烷稀释后,加入适量吸附剂和去离子水,经分散式固相萃取净化,浓缩定容后应用Eclipse XDB-C18色谱柱(4.6 mm×150 mm,5μm)对苯并(a)芘含量进行分析,流动相以乙腈-水(v:v=88:12)进行等度洗脱,采用荧光检测器(激发波长Ex=384 nm,发射波长Em=406 nm)检测,外标法定量。依据JJF 1135-2005《化学分析测量不确定度评定》中相关规定,考查称量、定容体积、标准曲线、仪器测量重复性和回收率等引入不确定度的主要因素,并对不确定度的各分量进行计算和合成。结果当植物油中苯并(a)芘含量为4.33μg/kg时,在95%的置信区间下,其扩展不确定度为0.66μg/kg(k=2)。评定结果表明,标准曲线拟合和标准溶液的配置产生的不确定度对合成不确定度的影响较大,而样品称量所引入的不确定度较小可忽略不计。结论该评定方法客观准确,适用于分散式固相萃取结合高效液相色谱法测定植物油中苯并(a)芘含量的不确定度分析,对检测结果准确度的提高具有参考意义。
OBJECTIVE To establish an analytical method of uncertainty for determination of benzo (a) pyrene in vegetable oils by dispersive solid phase extraction coupled with high performance liquid chromatography. Methods The sample was diluted with n-hexane, and then the appropriate amount of adsorbent and deionized water were added. The sample was purified by dispersive solid phase extraction (SPE). The sample was concentrated on a C18 column (4.6 mm × 150 mm, ) Pyrene, the mobile phase was isocratically eluted with acetonitrile-water (v: v = 88:12) and detected by fluorescence detector (excitation wavelength Ex = 384 nm and emission wavelength Em = 406 nm) Legal quantity. According to JJF 1135-2005 “Chemical analysis of measurement uncertainty” in the relevant provisions of the test weighing, volumetric capacity, the standard curve, the instrument measurement repeatability and recovery rate of the main factors that lead to uncertainty, and uncertainty Of the components of the calculation and synthesis. Results When the content of benzo (a) pyrene in vegetable oil was 4.33μg / kg, the uncertainty of expansion was 0.66μg / kg (k = 2) under the 95% confidence interval. The evaluation results show that the uncertainty caused by the fitting of the standard curve and the standard solution has a great influence on the synthesis uncertainty, but the uncertainty introduced by the sample weighing is negligible. Conclusion The method is objective and accurate and is suitable for the determination of the benzo (a) pyrene content in vegetable oils by dispersive solid-phase extraction combined with high performance liquid chromatography. It is of great value to the accuracy of detection results.