Determination of gaseous formaldehyde by derivatization using magnetic multiwalled carbon nanotubes (MWCNTs) modified with 2,4-dinitrophenylhydrazine (DNPH) and high-performance liquid chromatography – ultraviolet detection (HPLC-UV)

Formaldehyde, a common indoor air pollutant, may have adverse effects on human health. The detection of formaldehyde is vital for assessing personal exposure risks. In this study, a method for indoor gaseous formaldehyde detection was developed based on the derivatization of formaldehyde by magnetic multi-walled carbon nanotube (MWCNT)-supported 2,4-dinitrophenyl hydrazine (DNPH) and analysis by high-performance liquid chromatography with ultraviolet detection. The method exhibited high derivatization efficiency due to the immobilized DNPH and rapid separation of derivatives and impurities due to the magnetic solid material. The optimal analysis conditions were 30 min for the derivatization reaction time and 35 °C for the derivatization reaction temperature in an acidic reaction medium. Under these conditions, the linear range for the proposed formaldehyde detection method was from 0.01 to 5.00 mg/L, and the detection limit was 0.005 mg/L. This formaldehyde detection method is advantageous due to its simplicity, sensitivity, linearity, and stability.