A New Spectrophotometric Method for Instant Determination of Formaldehyde in Dope

In the presence of FeCl3 and HCl,formaldehyde can form a purple complex with peptone.The complex exhibited maximum absorption at 555 nm.The absorption was linearly proportional to the complex concentration in the formaldehyde concentration range of 1~25 μg/10mL with a correlation coefficient(r2) of 0.9997.The detection limit was 0.05 μg/mL.This method was applied to the determination of formaldehyde in dope discoloring by the active carbon.The recoveries were 96.46%~103.32% and the relative standard deviations were 1.36%~2.09%(n=6).