Sahin Uğur, Kartal Senol, Ulgen Ahmet
Department of Chemistry, Faculty of Arts and Sciences, Erciyes University, Kayceri, Turkey.
Anal Sci. 2008 Jun;24(6):751-7. doi: 10.2116/analsci.24.751.
A coprecipitation method has been developed for the determination of Cr(III), Mn(II), Fe(III), Co(II), Cu(II), Cd(II) and Pb(II) ions in aqueous samples by flame atomic absorption spectrometry (FAAS) with the combination of pyridine, nickel(II) as a carrier element and potassium thiocyanate as an auxiliary complexing agent. The obtained coprecipitates were dissolved with nitric acid and measured by FAAS. The coprecipitation conditions, such as the effect of the pH, amounts of nickel, pyridine and potassium thiocyanate, sample volume, and the standing time of the precipitate formation were examined in detail. It was found that the metal ions studied were quantitatively coprecipitated with tetrakis(pyridine)-nickel(II)bis(thiocyanate) precipitate (TP-Ni-BT) in the pH range of 9.0 - 10.5. The reliability of the results was evaluated by recovery tests, using synthetic seawater solutions spiked with the analyte metal ions. The obtained recoveries ranged from 96 to 101% for all of the metal ions investigated. The proposed method was validated by analyses of two certified reference materials (NIST SRM 2711 Montana soil and HPS Certified Waste Water Trace Metals Lot #D532205). It was also successfully applied to seawater and dialysis solution samples. The detection limits (n = 25, 3s) were in the range of 0.01-2.44 microg l(-1) for the studied elements and the relative standard deviations were < or =6%, which indicated that this method could fully satisfy the requirements for analysis of such samples as seawater and dialysis solution having high salt contents.
已开发出一种共沉淀法，通过火焰原子吸收光谱法（FAAS）结合吡啶、镍（II）作为载体元素和硫氰酸钾作为辅助络合剂，来测定水样中的Cr(III)、Mn(II)、Fe(III)、Co(II)、Cu(II)、Cd(II)和Pb(II)离子。所得共沉淀物用硝酸溶解，然后通过FAAS进行测定。详细考察了共沉淀条件，如pH值、镍、吡啶和硫氰酸钾的用量、样品体积以及沉淀形成的静置时间的影响。结果发现，在所研究的金属离子在pH值为9.0 - 10.5的范围内与四（吡啶）-镍（II）双（硫氰酸盐）沉淀（TP-Ni-BT）定量共沉淀。通过回收率测试评估结果的可靠性，使用添加了分析物金属离子的合成海水溶液。对于所有研究的金属离子，获得的回收率在96%至101%之间。通过分析两种有证标准物质（NIST SRM 2711蒙大拿土壤和HPS认证废水痕量金属批次#D532205）对所提出的方法进行了验证。该方法还成功应用于海水和透析液样品。所研究元素的检测限（n = 25，3s）在0.01 - 2.44 μg l(-1)范围内，相对标准偏差≤6%，这表明该方法能够完全满足分析高盐含量的海水和透析液等样品的要求。
