Abstract:

In sulfuric acid medium, hydrogen peroxide can oxidize and decolorize crystal violet under the catalysis
of formaldehyde, and the extent of decolorization is proportional to the content of formaldehyde. A new method was
established for the determination of trace formaldehyde. The factors affecting the rate of catalytic fading reaction were
investigated. Under the optimal conditions, the formaldehyde concentrations within a range of 0.4–2.0 μg/mL exhibited
a good linear relationship, the detection limit was 0.35 μg/mL and the relative standard deviation (RSD) of 1.03% for 11
repetitive determinations of 1.6 μg/mL formaldehyde solution. The proposed method is of high sensitivity and selectivity.
When it was applied in the detection of trace formaldehyde in beer, the spike recoveries were between 98.6% and 104.6%.

Key words: catalytic kinetic spectrophotometry, formaldehyde, crystal violet, hydrogen peroxide