Study on direct determination of sodium formaldehyde sulfoxylate in foods by pararosaniline hydrochloride colorimetry

Objective:To establish a method with high specificity and accuracy for the direct determination of sodium formaldehyde sulfoxylate in foods by pararosaniline hydrochloride colorimetry.Methods: The sample was distillated by steam water with acidic conditions followed by the addition of sodium hydroxide which produced sulfur dioxide and formaldehyde.The absorbance were determined by pararosaniline hydrochloride colorimetry at 560 nm.Results: The results were satisfactory between 0.02 mg~0.7 mg with good linearity of r=0.9996,lowest determination limit of 0.005 mg and higher recovery of 93.5%~99.7%.Conclusion: This simple and accurate method is suitable for the direct determination of sodium formaldehyde sulfoxylate in foods.