Abstract:
This research aimed to develop a colorimetric method for the determination of formaldehyde on a paper-based device, using 4-aminophenyl sulfone for surface modification of gold nanoparticles (AuNPs) with an amine group that can react with formaldehyde in the presence of hydroxylamine hydrochloride. The process resulted in the aggregation of modified gold nanoparticles (modified-AuNPs) induced by formaldehyde in the presence of hydroxylamine hydrochloride. To verify this aggregation, the modified-AuNPs were characterized using ultraviolet-visible spectroscopy (UV-vis) and Transmission electron microscopy (TEM). This method offers a high sensitivity and selectivity for the determination of formaldehyde over other chemical and ions. The color change of modified-AuNPs from red to blue can be monitored by naked eyes. The relevant calibration curves was linear in the range of 40 - 110 µg mL-1 (R2 = 0.9979) and the limit of detection was found to be 35 µg mL-1 by using ImageJ software for image processing. This developed method was applied to detect formaldehyde in real samples (e.g. food and environmental), which the results were in good agreement with those obtained from the standard methods.
