| Abstract | Mercury is widely considered to be among the highest priority environmental pollutants of continuing concern on the global scale. Normally, people expose mercury by consuming mercury contaminated food such as fish and sea food. Since, the concentration of mercury in natural water is very low, therefore, highly sensitive instrument for mercury measurement is high demand. Chemosensor is attractive method because high selectivity, sensitivity, quick response times, easy signal detection and portable which is convenient in the field application. Rhodamine hydrazine (RhH) is a dual chemosensor for Hg2+ ion detection. In present of Hg2+ ion, RhH is induced by Hg2+ ion, the color was changed from color less to deep pink which is easily for detection by naked-eye and fluorescence enhancement is occurred. RhH sensor present selective to Hg2+ ion over other metal ions including: Pb2+, Ni2+, Ag+, Zn2+, Fe2+, Ba2+, Ce4+, and Cu2+ , Na+, K+, Mg2+ and Ca2+ ions. Detection limit of RhH was found as 2 mg/l by the lowest color produced and the lowest detected of absorption intensity and 0.2 mg/l for lowest detected fluorescence intensity. The kinetics of RhH and Hg2+ ion chelation did not depend on the time progress both fluorescently and UV spectroscopically. Acidic condition of water also affects on RhH kinetics, since the open form of RhH was predominant in acidic condition therefore, pH of water should be concerned during RhH sensor application. Sunlight also effects the interaction of RhH with Hg2+ ion, exposure to sunlight induced color change of RhH’s solution. RhH strip was developed based on filter paper as a solid support, because it was generated very clear color upon interaction with Hg2+ ion, detection limit of RhH strip was found as 0.2 mg/l. Hg2+ ion of surface water and industrial wastewater from paint, fluorescent lamp wastewater were analyzed by ICP-OES as the non detectable level, since the detection limit of ICP-OES is between 1 to 10 μg/l which is lower than detection limit of RhH strip, hence RhH cannot be applied for detection of mercury in surface and industrial wastewater samples. Application of RhH strip on the synthetic wastewater containing concentration at 0 5, 10, 15, 20 mg/l, the results presented the quite high accuracy 100 % for 0 mg/l and 80% for 20 mg/l concentration of Hg2+ ion. In conclusions, RhH sensor was able to detect Hg2+ ion with high selectivity, the sensitivity of strip was not high enough to be applied for the water samples of surface water and industrial wastewater. However, RhH sensor can be applied for other sources of water which contain high concentration of Hg2+ ion such as wastewater from chlor-alkali and electroplating industries and processing water which contain high concentration of mercury. |