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利用化学反应和气相色谱法测定食盐中无机碘。在强酸介质中 ,食盐中的无机碘被亚硝酸钠还原成游离碘 ,游离碘遇丙酮立刻生成碘丙酮 ,用气相色谱电子捕获检测器测定其含量。气相色谱柱为 6 % DEGS+ 1% H3PO4/Chrom osorb W AW DMCS填充柱 ,柱温为 80℃ ,三溴甲烷为内标物。碘丙酮和三溴甲烷的保留时间分别为 4.0 m in和 1.9m in。样品的平均回收率为 10 1.2 % ,相对标准偏差为 1.9%。
Determination of inorganic iodine in salt by chemical reaction and gas chromatography. In strong acid medium, the inorganic iodine in salt is reduced to free iodine by sodium nitrite, iodine and acetone are generated in the free iodine with acetone, and its content is determined by gas chromatography electron capture detector. The GC column was a 6% DEGS + 1% H3PO4 / Chromosorb W AW DMC DMC column with a column temperature of 80 ° C and tribromomethane as the internal standard. The retention times of iodine acetone and tribromomethane were 4.0 m in and 1.9 m in, respectively. The average recovery of the sample was 10 1.2% with a relative standard deviation of 1.9%.