凯氏定氮-气相色谱法测定蓝莓利口酒中微量甲醇的含量

Determination of the Content of Trace Methanol in Blueberry Liqueur by the Kjeldahl Nitrogen Gas Chromatography

利用凯氏定氮仪蒸馏蓝莓利口酒中的甲醇,加入叔戊醇作为内标物,利用气相色谱法测定甲醇的含量。采用白酒分析专用毛细管柱CP-Wax57CB(50 m×0.25 mm×0.2μm)分离,用氢火焰离子检测器检测。进样口温度220℃,柱温35℃,程序升温:35℃,保持4min;5℃/min升至80℃;25℃/min升至200℃,保持3 min,检测器温度260℃,用内标法定量。结果表明,在100~1 000 mg/L的线性范围良好,线性方程为Y=3.42×10^(-3)X-4.152×10^(-2),相关系数R为0.999 37,回收率为88.72%~96.99%,检出限为1.2 mg/L。该方法能快速蒸馏样品,操作简单,准确度高,稳定性好,能快速大批量检测蓝莓利口酒中微量甲醇的含量。

The methanol in blueberry liqueur was distilled by Kjeldahl apparatus,and the content of methanol was determined by gas chromatography with tert amyl alcohol as internal standard.Special capillary column CP-Wax57CB(50 m×0.25 mm×0.2μm)as separated for white spirit,detected by hydrogen flame ion detector.Inlet temperature was 220℃,Column temperature was 35℃,Program temperature:35℃,was keeped 4min;5℃/min to 80℃;25℃/min to 200℃,was keeped 3min,the detector temperature is 260℃,internal standard method was used for quantitative analysis.The results show that the linear range in 100~1 000 mg/L was good,linear relationship is Y=3.42×10-3X-4.152×10-2,correlation coefficient is 0.999 37,recovery rate of 88.72%~96.99%,the detection limit is 1.2mg/L.The method can be used for rapid distillation of samples with simple operation,high accuracy and good stability.It can rapidly and quantitatively detect the content of trace methanol in blueberry liqueur.