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适量的I2与淀粉溶液可形成最大吸收波长为580 nm的蓝色配合物,其浓度与吸光度成正比。往碘-淀粉体系加入适量的NaOH后,I2与NaOH生成的NaIO能定量地将葡萄糖氧化成葡萄糖酸,过量的NaIO则发生歧化生成NaIO3和NaI。将反应后的溶液调成酸性后,NaIO3与NaI反应重新生成I2。在葡萄糖含量1.00μg/mL～8.00μg/mL的范围内,碘与淀粉溶液与葡萄糖反应前后吸光度差(ΔA)与加入的葡萄糖含量(p)有良好的线性关系,线性回归方程为ΔA=0.196 8p+0.035 0,线性相关系数r=0.999 3。方法用于测定蜂蜜样品中葡萄糖含量,测得葡萄糖含量为29.4%,相对标准偏差为0.6%(n=6),加标回收率为98%～102%(n=6),方法检出限为0.015 2μg/mL,测定结果与国标高效液相色谱法相近,可以推广应用。
The appropriate amount of I2 and starch solution can form a blue complex with a maximum absorption wavelength of 580 nm, the concentration of which is proportional to the absorbance. After adding appropriate amount of NaOH to iodine-starch system, NaIO produced by I2 and NaOH oxidized glucose to gluconic acid quantitatively, while excess NaIO disproportionated to produce NaIO3 and NaI. After the reaction solution is adjusted to acidic, NaIO3 reacts with NaI to regenerate I2. In the range of 1.00μg / mL to 8.00μg / mL, there was a good linear relationship between absorbance difference (ΔA) and glucose content (p) before and after the reaction between iodine and starch solution and glucose, and the linear regression equation was ΔA = 0.196 8p + 0.035 0, linear correlation coefficient r = 0.999 3. The method was applied to the determination of glucose in honey samples. The measured glucose content was 29.4%, the relative standard deviation was 0.6% (n = 6), the recoveries were 98% -102% (n = 6) 0.015 2μg / mL, the determination of results and the national standard high performance liquid chromatography similar to promote the use.