用变色酸光度法同时测定甲醇与甲醛的初步实验

甲醇和甲醛往往同时存在，为了能同时检测它们，采用变色酸光度法对甲醇、甲醛的检测进行了探讨性实验。先用变色酸比色法直接测定甲醛，然后在酸性条件下用高锰酸钾将甲醇氧化成甲醛后再与变色酸反应进行测定，这时的测定值为甲醇与甲醛之总量，扣除甲醛之量后就得到甲醇量。甲醛的最低检出浓度为2mg／L，测定上限为20mg／L，方法的精密度和准确度也比较好。

Experiment of determining methylalcohol and formaldehyde simultaneously by off-color acid spectrophotography

Off-color acid spectrophotography is adopted in discussing experiments to determine carbinol and formaldehyde simultaneously,since they exist often atthe same time. After formaldehyde is determined directly by off-color acid colorimetry,formaldehyde is oxidized under acid condition by potassium permanganate into formaldehyde which is in turn reacted with off-color acid and then measured. The measured valueis the sum of the amount of carbinol and formaldehyde that minus the value of formaldehyde is the amount of carbinol. The inferior cone of formaldehyde determined by thismethod is 2 mg/L,while the superior limit is 20 mg/L. This method is also more preciseand accurate.