碘酸钾碘盐自然存放13年碘的损失研究

Experimental study on iodine loss in natural storage KIO3-iodized salts during 12 years

目的研究碘酸钾(KIO3)碘盐的稳定性.方法以40目粉碎的KIO3用干混法生产的23份KIO3碘盐散装暴露在空气中常温常湿存放13年,用直接滴定法测定不同存放期碘盐的含碘量.结果存放22个月内检验盐碘量14次,碘下降0.31%;存放32个月碘下降6.38%;存放36个月碘下降9.10%;存放60个月碘下降10.28%;存放84个月碘下降19.63%;存放96个月碘下降25.51%;存放108个月碘下降28.61%;存放120个月碘下降30.40%;存放144个月碘下降39.50%;存放156个月碘下降42.48%;其中第36、54、60、84、96、108、120、144、156个月存放期样品均有程度不同的碘下降.结论KIO3碘盐化学性质较稳定,其碘盐商业流通周期内盐碘量基本不变,13年实验结果提示,它确属国内外所推崇的长效碘盐,并证明新碘盐标准(GB 5461-2000)的盐碘量统一为1种标准(35±15)mg/kg是正确的.

Objective To study the stability of KIO3-iodized salts which were produced by dry mixed method and naturally stored between 0 and 144 months (12 years). Methods Twenty times of determination for iodine contents were conducted in 23 samples of KIO3-iodized salts which were produced by dry mixed method through 40-aperture-sieve pulverization and which were naturally stored in bulk for 13 years. Results The results showed that iodine level was basically not changed after 22 month, decreased 6.38% after 32 month, declined 9.10% alter 36 month, reduced 10.28% after 60 month, lowered 19.63% after 84 month, and lowered 25.51% after 96 month, lowered 28.61% after 108 month, lowered 30.40% after 120 month, lowered 39.50% after 144 month, lowered 42.48% after 156 month. Iodine level in all samples stored after 36, 54,60,84,96,108,120,144,156 month, were decreased in different degrees. There were a negative correlation between the rates of iodine decreasement and iodine level in the sample. Conclusions The chemical quality of iodized salts is stable and the level are not changed basically in commercially circulated periods. This study has shown that a criterion of qualified iodine concentration.