Determination of mercury in some water samples using the gold-coated trap CV-AAS method

In this study, mercury was determined by gold-coated trap CV-AAS method, in the samples taken different regions of Muğla Province Menteşe District, Akyaka Azmak river water, Akyaka shore surface sea water, Yatağan Stream, Gökpınar Spring water, Gemlik Bay sea water, İzmir Mercury , Aliağa Bay seawater and Gebze Organized Industrial Zone. The aim of this study is; to develop an accurate, sensitive and low cost online trap method and to apply the developed method to the total mercury determination in various water samples. Before analyzing the water samples, optimum values of the parameters that can directly affect the analytical signal of mercury were determined experimentally. These parameters were found out as; collecting temperature 96 ºC, stripping temperature 810 ºC, collection time 210.0 s, argon gas flow rate 150 mL / min, hydrogen gas flow rate at collection time 3.79 mL / min, hydrogen gas flow rate during stripping 7.59 mL / min, NaBH4 concentration 0.3% (w / v), NaOH concentration 0.5% (w / v), sample flow rate 4.56 mL / min, HCl flow 4.89 mL / min NaBH4 flow rate 4.95 mL / min. By keeping the trap temperature constant at 96 C, the mercury hydride species formed were collected on the gold covered W-spiral trap, and after 210.0 seconds collection stage, the temperature of the trap was raised to 810 C and the mercury species collected on the gold covered W-spiral surface were removed from the surface to the quartz T-tube atomizer, provided to reach. In order to compare the developed trap method and the conventional CV-AAS method, mercury deterination was also conducted with conventional CV-AAS method. For the CV-AAS method, LOD and LOQ values were calculated as 0.623 µg / L, 2.056 µg / L, respectively, and the % RSD was determined as 7.19. The LOD and LOQ values were calculated as 0.048 µg / L and 0.160 µg / L, respectively, for gold coated-trap, and the % RSD was determined as 4.28. With the developed trap method, the sensitivity is increased approximately 13 times compared to the conventional CV-AAS method.The accuracy of the method has been tested with the NIST SRM 1641e (Mercury in Water) standard reference material. According to the measurement results obtained, it was concluded that the sensitivity, precision and accuracy of the trap method were satisfactory. The recently developed trap method has been successfully applied in the analysis of total mercury in water samples. Keywords: Mercury, CV-AAS, W-Coil Atom Trap, Gold coated