抑制褪色光度法测定啤酒中微量二氧化硫  

Determination of Trace Sulfur Dioxide in Beer by Using Inhibition Fading Spectrophotometry

作　　者：徐刚[1] 董文丽[1] XU Gang;DONG Wenli(College of Chemisry and Chemical Engineering,Chongqing College of Science and Technology,Chongqing 401331,China)

机构地区：[1]重庆科技学院化学化工学院,重庆401331

出　　处：《理化检验（化学分册）》2021年第3期264-267,共4页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

摘　　要：基于在硫酸介质中二氧化硫对溴酸钾氧化亚甲基蓝(MB)褪色具有抑制作用,建立了抑制褪色光度法快速测定啤酒中微量二氧化硫的方法。在25mL比色管中依次加入1mol·L^(-1)硫酸溶液、2×10^(-4)mol·L^(-1)MB溶液、0.1mol·L^(-1)溴酸钾溶液和经氢氧化钠和硫酸处理好的样品溶液,于50℃水浴中加热3.0min,在660nm处测量该体系的吸光度A及空白样品体系的吸光度A_(0),计算吸光度差值ΔA(ΔA=A-A_(0))。结果显示,二氧化硫的质量浓度在0.04~0.4mg·L^(-1)内与ΔA呈线性关系,检出限(3s/k)为0.001mg·L^(-1)。对实际样品进行加标回收试验,回收率为96.5%~101%,测定值的相对标准偏差(n=11)为1.8%~2.8%。用该方法分析熟啤和生啤,将得到的测定值与国家标准方法GB 5009.34-2016的进行了比对,相对误差为-1.5%~2.0%。Based on the principle that sulfur dioxide can inhibit the fading of MB oxidized by potassium bromate in sulfuric acid medium,a method for rapid determination of trace sulfur dioxide in beer by inhibiting fading spectrophotometry was established.1 mol·L^(-1)sulfuric acid solution,2×10^(-4)mol·L^(-1)MB solution,0.1 mol·L^(-1)potassium bromate solution and sample solution treated with sodium hydroxide and sulfuric acid were added sequentially to the 25 mL colorimetric tube,the mixed solution was heated in a water bath at 50℃for 3.0 min.The absorbance of the system(A)and the blank sample system(A_(0))were measured at 660 nm,to obtain the difference in absorbance(ΔA,ΔA=A-A_(0)).The results showed that the mass concentration of sulfur dioxide had a linearity relationship withΔAin the range of 0.04-0.4 mg·L^(-1),with detection limit(3 s/k)of 0.001 mg·L^(-1).The recovery test was made on the actual sample by the standard addition method,giving recoveries ranged from 96.5%to 101%,and RSDs(n=11)of determined values were found in the range of 1.8%-2.8%.The proposed method was used in the analysis of cooked beer and draft beer,and determined values obtained were compared with those obtained by national standard method of GB 5009.34-2016,with relative error in the range of-1.5%-2.0%.

关 键 词：亚甲基蓝 溴酸钾 抑制褪色光度法 二氧化硫 啤酒 

分 类 号：O657.32[理学—分析化学]