Dipartimento di Chimica Generale, Università di Pavia, via Taramelli 12, 27100, Pavia, Italy.
Departament de Química, Universitat de Lleida, Rovira Roure 191, 25198, Lleida, Spain.
Anal Bioanal Chem. 2010 May;397(1):389-394. doi: 10.1007/s00216-009-3439-8. Epub 2010 Jan 23.
Absence of gradients and Nernstian equilibrium stripping (AGNES) is a recently developed electroanalytical technique specifically designed for the direct determination of free concentrations of metal ions. AGNES is applied here to the determination of free Zn concentration in a river water sample. The method has been validated with synthetic solutions of low ionic strengths containing Zn and 2,6-pyridinedicarboxylic acid and then applied to synthetic river waters and to a natural sample collected from Besòs River in Montcada i Reixac (Catalonia, North-Eastern Spain). In the river sample, an average free Zn concentration of 12.8(4) nM was obtained, while the total dissolved Zn concentration was 0.51(8) microM. To control and maintain pH and pCO(2) constant during AGNES measurements, a novel device for N(2)/CO(2) mixed purging has been developed.
无梯度和能斯特平衡去极（AGNES）是一种最近开发的电分析技术，专门用于直接测定金属离子的游离浓度。AGNES 现被应用于测定河流水样中的游离锌浓度。该方法已通过含有锌和 2,6-吡啶二甲酸的低离子强度合成溶液进行了验证，然后将其应用于合成河水和取自西班牙东北部蒙卡达伊雷雅克的贝斯奥河的天然水样。在河流水样中，获得了平均游离锌浓度为 12.8(4)nM，而总溶解锌浓度为 0.51(8)μM。为了在 AGNES 测量过程中控制和保持 pH 值和 pCO2 恒定，开发了一种用于 N2/CO2 混合吹扫的新型设备。
