Discussion about Fractional Determination of Formaldehyde and Methanol in Formalin

Abstract

On the fractional determination of formaldehyde and methanol in formalin, the fixed difference of methanol determination value yielded from a colorimetric analysis using chromotropic acid and a volumetric analysis using sodium sulfite adopted in the JIS K 1502.
The former determination value of methanol in formalin was average 14. 0%, and the later was 8. 8%, respectively.
The author therefore presumed that formaldehyde in formalin was responsible for giving effect on the oxidation reaction of methanol to formaldehyde in H₃PO₄-KMn0₄ solution. Formaldehyde is belong to the aldehyde compoundt. Addition of aldehyde compounds of acetaldehyde-ammonia ([CH₃CH (NH₂) OH] ₃) made an increase in sensitivity on the determination of methanol with the conventional chromotropic acid method.
The principle of the improved method was applicable to the det ermination of methanol and methylester in atmosphere using para-rosaniline.