A simple and fast colorimetric method for detection of hydrazine in water samples based on formation of gold nanoparticles as a colorimetric probe

It is critical to be able to detect and quantify hydrazine under aqueous conditions with high sensitivity and selectivity. A colorimetric sensor for hydrazine with high selectivity and sensitivity by gold nanoparticles (AuNPs) within about 4–5 min at room temperature is presented. In this paper, the reduction of AuCl4− to gold nanoparticles by hydrazine compound produced very intense surface plasmon resonance peak of AuNPs. The formation of gold nanoparticles as a result of the redox reaction in water samples was identified by measuring the localized surface plasmon resonance (LSPR) absorption. With increasing hydrazine concentration, the LSPR intensity displays linear response with the hydrazine content over the range from 6.0 to 40.0 × 10−6 M, with a detection limit of 1.1 × 10−6 M. The relative standard deviation (R.S.D.) for determination of 10 × 10−6 M and 28 × 10−6 M of hydrazine was 3.2% and 0.68% (n = 6), respectively. The proposed method is convenient, low-cost and free of complex equipment, making it possible to successfully analyze hydrazine in industrial water samples (boiler and cooling water) and river water.