关键词: 挥发酚, 溴化容量法, GB 7491-1987, HJ 502-2009

Abstract: Two standards for determination of volatile phenolic compounds with bromine method, GB 7491-1987 and HJ 502-2009, were compared including determination range, analysis procedure, consumption of potassium bromated-potassium bromide solution and titrant, precision and accuracy. Comparison results show that in HJ 502-2009 standard method, the determination range of volatile phenolic compounds (0.1-45.0 mg/L) is definite, which is not clear in GB 7491-1987; the content of precision and accuracy is added, and sample pre-distillation is only once, which is twice in GB 7491-1987. According to HJ 502-2009 standard method, for 100 mL distillate, the adding volume of potassium bromated-potassium bromide solution is fixed to 3 mL, thus one blank test is enough for multiple samples analysis, which is more suitable to batch analysis. When the content of volatile phenolic compounds in 100 mL distillate is 2.35 mg, the consumptions of potassium bromated-potassium bromide solution of these two standard method are the same; when the content of volatile phenolic compounds in 100 mL distillate is less than 2.35 mg, the consumption of potassium bromated-potassium bromide solution and sodium thiosulfate standard solution in HJ 502-2009 standard method is more than those in GB 7491-1987; however, it is contrary when the content of volatile phenolic compounds in 100 mL distillate is more than 2.35 mg. It is suggested to change the fixed volume of potassium bromated-potassium bromide solution from 3 mL to 2.5 mL, and the content of volatile phenolic compounds in 100 mL distillate should be less than 2.35 mg for easy operation and better accuracy.

Key words: volatile phenolic compounds, bromine method, GB 7491-1987, HJ 502-2009