Colorimetric sensor based on modified AuNPs for determination of arsenic in water samples

Accurate determination of arsenic as a water pollutant heavy cation in real samples is of importance due to its carcinogenic and pathogenic effects on human health especially heart and digestion systems [1]. AuNPs present interesting optical properties due to their strong surface plasmon resonance (SPR) absorptions in the visible region and their ease of preparation and stability. Modification of AuNPs and using them as colorimetric sensors is one of the most utilized methods for analytical determinations which exhibits high selectivity toward different analytes by using a wide variety of organic modifiers [2, 3].In this study, AuNPs modified with a newly synthesized organic modifier were used as colorimetric sensors for selective, sensitive and inexpensive spectrophotometric determination of arsenic in drinking water samples. Aggregation of modified AuNPs caused by their interaction with arsenic ions results in the change of the color of solution from red to violet which is proportional to the concentration of arsenic. The effects of pH, NaCl, time and the concentration of organic modifier were studied and optimized. Analytical figures of merit were investigated and the accurcy of proposed method was confirmed by recovery experiments using standard addition method.