催化动力学光度法测定啤酒中痕量甲醛

Catalytic Kinetic Spectrophotometric Determination of Trace Formaldehyde in Beer

在硫酸介质中,甲醛能催化过氧化氢氧化结晶紫的褪色反应,其褪色程度与甲醛的含量呈正比,以此建立一种测定啤酒中痕量甲醛的新方法,研究影响该反应速率的条件.结果表明,最佳实验条件下,甲醛在质量浓度0.4～2.0 μg/mL范围内与吸光度呈良好的线性关系.方法的检出限为0.35 μg/mI,对质量浓度1.6μg/mL甲醛标准溶液进行11次平行检测,得到相对标准偏差为1.03％,该方法的灵敏度高、选择性好,适用于啤酒中痕量甲醛的检测,加标回收率为98.6％～104.6％,结果令人满意.

In sulfuric acid medium, hydrogen peroxide can oxidize and decolorize crystal violet under the catalysis of formaldehyde, and the extent of decolorization is proportional to the content of formaldehyde. A new method was established for the determination of trace formaldehyde. The factors affecting the rate of catalytic fading reaction were investigated. Under the optimal conditions, the formaldehyde concentrations within a range of 0.4-2.0 μg/mL exhibited a good linear relationship, the detection limit was 0.35 μg/mL and the relative standard deviation （RSD） of 1.03% for 11 repetitive determinations of 1.6 μg/mL formaldehyde solution. The proposed method is of high sensitivity and selectivity. When it was applied in the detection of trace formaldehyde in beer, the spike recoveries were between 98.6% and 104.6%.