The standard method to determine the chlorides in solutions

GB 13580.9—92 mercuric thiocyanate high iron spectrophotometry

was improved and applied to detecting the chloride ion in common chemical cleaning agents.A pretreatment method using burning to eliminate the influence of complex and chroma on the determination was presented

and its reliability was verified.Moreover

the influence of this method on the detection result was analyzed.Results show that

for the cleaning agents with simple components

the chloride ion can be detected by spectrophotometric method directly.While for the one with complex compounds

the optimal burning temperature range during pretreatment process is between 540 ℃ and 560 ℃.The main way bringing chloride ion impurities is by ceramic crucible and NaOH

and filtration has no influence on the detection.This modified method has good stability

accuracy and reliability.The average recoveries of standard addition for glycolic acid

formic acid

hydrogen peroxide and NaOH are larger than 90.0%

and that of the citric acid and its corrosion inhibitor are between 93.0% and 102.0%.