Colorimetric and “turn-on” fluorescence detection of saccharin using silver nanoparticles-graphene oxide composite

Abstract

Saccharin (SAC) is a synthetic sweetener used in soft drinks and candies. Consumption of excess SAC leads to several health problems. Therefore, developing a simple method to detect its concentration in food stuffs and soft drinks is very important. The present study describes a simple colorimetric method for SAC determination using graphene oxide-silver nanoparticles (GO-AgNPs) composite solution. The yellow color GO-AgNPs was changed to reddish brown while adding 600 μM SAC and the emission of GO was “turn off” after the formation of AgNPs. However, the emission was “turn on” after the addition of SAC. This was ascribed to the strong interaction between sulfonamide groups of SAC with AgNPs, resulting the leaching of AgNPs from GO surface. The emission intensity increases linearly when SAC concentration increases from 500 nM to 1 mM with R2 = 0.9971 and the limit of detection was 0.7 mg L−1 (S/N = 3). The present GO-AgNPs composite was also used to selectively determine SAC containing 1400-fold higher concentration of interferents. Finally, the real sample analysis was carried out by determining SAC in candies and soft drinks by using GO-AgNPs.