Spectrophotometric Determination of Squaric Acid

The reaction conditions of squaric acid and FeCl3 color system were investigated and the spectrophotometric method for determination of squaric acid was developed.At pH 2.1 HCl-HAc,the colored complex exhibits maximum absorption at 505nm,and the linear range for determination of squaric acid is 0.05—1.0mmol/L with a correlation coefficient of 0.9995.The detection limit of the proposed method is 0.005mmol/L.This method is simple and convenient,and has been applied to the determination of squaric acid in samples with satisfactory results.