HG/T2785-2012 Ammonium Bisulfite for Industrial Use
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- Apr 7,2026
Summary
The arithmetic mean of parallel determination results was taken as the final determination result.
The absolute error of parallel determination results does not exceed 0.35%.
5.3.5 Allowable Difference
The arithmetic mean of parallel determination results was taken as the final determination result.
The absolute error of parallel determination results does not exceed 0.35%.
5.4 Total Ammonium Content
The sum of ammonium sulfite and ammonium bisulfite expressed as mass percentage (X3) is calculated according to Equation (3):
X3=X1+X2…………………………（3）
Where: X1 — measured content of ammonium bisulfite,%;
X2 — Measured content of ammonium sulfite,%
5.5 Ammonium bisulfite/ammonium sulfite ratio
The ratio of ammonium sulfite to ammonium sulfite expressed as a percentage by mass (X4) is calculated according to Equation (4):
……………………（4）
Where: X1 — measured content of ammonium bisulfite,%;
X2 — Measured content of ammonium sulfite,%
5.6 Determination of Ammonium Thiosulfate Content
5.6.1 Principle
The sample was titrated with ammonium thiosulfate in a pH 5–6 solution using starch solution as the indicator and formaldehyde solution as the masking agent. The ammonium thiosulfate content was calculated based on the iodine solution dosage.
response equation ：
2（NH4）2S2O3+I2→（NH4）2S4O6+2NH4I