DETERMINATION OF FORMALDEHYDE CONTENT IN THE AMINOMETHYLATED PRODUCT OF TANNIN BY POTENTIOMETRIC TITRATION

In this paper a potentiometric titration was used to improve the neutral sodium sulfite method for determining the content of formaldehyde, and the accuracy and influential factors were discussed. The results of quantitative determination of formaldehyde in the aminomethylated product of tannin showed that the mensurative rate of formaldehyde in reaction system was 93.82%, r =0.999, the recovery rate of the blank test was 97.74%, r = 0.999, temperature was controlled at 15-20℃, laying time was between 1 h for stabilization. This method eliminated the defects of coloured and cloudy liquor which blurred the end point of titration by indicator. The range of electric potential was wide, the repetition and accuracy of data were perfect. This method is quick, simple and easy to control.