Spectrophotometric Determination of Formaldehyde in Water Sample with Amino Acid-Acetylacetone

Conditions for the color reaction of formaldehyde with acetylacetone by using amino acids instead of aq. ammonia or ammonium acetate as the donor of -NH2 group were tested and a spectrophotometric method for determination of formaldehyde in water sample with glycine and acetylacetone as reagents was proposed. The optimized conditions found were as follows: ① amount of 0.12 mol·L-1 glycine derivatizing agent: 2 mL; ② temperature of reaction: 50 ℃; ③ time of reaction: 15 min; ④ pH of reaction system: 4.7. Linear relationship between values of absorbance and mass concentration of formaldehyde was obtained in the range of 0.2-1.0 mg·L-1, with detection limit of 5 μg·L-1. Values of recovery found by standard addition method were over 98.0%,and values of RSD′s (n= 6) less than 4%. The proposed method was used in the analysis of sample of surface water, giving results of formaldehyde contents in consistency with values found by GB method.