Determination of cesium using nickel hexacyanoferrate by stripping voltammetry

The determination of cesium ions (Cs⁺) is important for various applications, including resource utilization, environmental monitoring, and human health. Electrochemical sensors, with their inherent advantages, stand out as an ideal choice for Cs⁺ detection. However, electrode materials for Cs⁺ sensors usually face problems such as poor selectivity and complex synthesis. Herein, a method employing nickel hexacyanoferrate (NiHCF) as the electrode material for stripping voltammetry in the determination of Cs⁺ was proposed. Both adsorption and electrochemical intercalation exhibited selectivity. In the presence of interfering ions at a 10 : 1 molar ratio to Cs⁺, Cs⁺ was still preferentially intercalated in NiHCF. However, electrochemical intercalation exhibits superior selectivity for Cs⁺ compared to adsorption. Meanwhile, the effect of adsorption on the detection was minimized by electrochemical intercalation. Based on the standard addition method, Cs⁺ was determined using both adsorption and electrochemical intercalation methods. The error reduced significantly from 32.7% above the theoretical value through adsorption to 9.5% below the theoretical value through electrochemical intercalation. This approach not only enhanced the measurement accuracy but also reduced the costs associated with both measurement and preparation. The study proposed a cost-effective and rapid method for Cs⁺ measurement using Prussian blue analogs.