Test solution of pyrogallic acid was prepared by adding formic acid as antionxidative stabilizer, thus the measuring instability due to the oxidability of pyrogallic acid was overcome.

• 通过加入甲酸作为焦性没食子酸试液的抗氧化保护剂，解决了由于试样的氧化而导致测定值不稳定的问题。