Objective To establish a high-performance liquid chromatography (HPLC) method for determination of formaldehyde in drinking water.

Methods Formaldehyde reacted with 2, 4-dinitrophenylhydrazine in an acidic medium in a water bath at 55℃ for 40 minutes to form the formaldehyde-2, 4-dinitrophenylhydrazone product, which was extracted with n-hexane. The product was separated by the C₁₈ (250 mm×4.6 mm, 5 μm) column of high-performance liquid chromatograph, and eluted with acetonitrile-water (v: v, 70:30). The detection was carried out at the maximum absorption wavelength of 355 nm.

Results The content of formaldehyde in drinking water ranged from 0.006 μg/mL to 2.00 μg/mL, and the correlation coefficient (r) was greater than 0.9992, indicating a good linear relationship. The detection limit was 0.002 μg/mL. The spike recovery rate of the method was 90.0%-106.0%, with the relative standard deviation of 1.20%-3.79%. Acetaldehyde had no interference with the experimentation at 4.00 μg/mL.

Conclusion The established method is simple to operate, has high sensitivity and good repeatability, and allows the generation of accurate results, meeting the requirements for measurement of trace formaldehyde in drinking water.