Adsorption voltammetric determination of μg 1−1 levels formaldehyde via in situ derivatization with Girardʹs reagent T

The adsorptive voltammetric behaviour of formaldehyde (HCHO) after its in situ derivatization with trimethylaminoacetohydrazide chloride (Girardʹs reagent T) at a hanging mercury drop electrode (HMDE) was investigated in NH3-NH4Cl (pH 9.7) solution. The results showed that the adduct of HCHO with Girardʹs reagent T can be adsorbed on the surface of the HMDE, yielding one peak at −1280 mV (vs AgAgCl electrode), corresponding to the reduction of the adduct. The limit of detection was as low as 8.0 × 10−8 mol dm−3 (corresponding to 2.4 μg dm−3 of HCHO). The linear range of the method was 2.0 × 10−7~8.0 × 10−6 mol dm−3. The sensitivity of the method allows its application for the direct determination of HCHO in rain water samples.