Spectrophotometric Determination of Cd(Ⅱ) in Environmental Water Samples with Cadion in the Presence of Triton X-114 Surface Active Agent

It is vital to monitor the cadmium (Cd) content in environmental water over time, as it is a prerequisite to prevent and control Cd contamination. Spectrophotometric determination of Cd was simple, rapid and well established. However, low sensitivity limits the application of Spectrophotometry to determine Cd content in environmental water samples. The sensitivity of Cd can be significantly improved for Spectrophotometry by using the surface active agent Triton X-114. In a KOH medium, Cd ions react with cadion to form orange complex. In tests, the maximum absorption and molar absorptivity for the orange complex were 470 nm and 1.25×10⁵L/(mol·cm), respectively. Beer′s law was obeyed for 0-10 μg of Cd in 25 mL of solution. The detection limit was 5.0 μg/L. Compared with Triton X-100 and other surface active agents, Triton X-114 can increase maximum of 49% to the molar absorption coefficient and reduced about 50% of the detection limit. This method is simple, fast and suitable to determine directly major or trace Cd in environmental water and industrial wastewater.