Using Cloud Point Extraction for Preconcentration and Determination of Iron, Lead, and Cadmium in Drinking Water by Flame Atomic Absorption Spectrometry

The determination of heavy metals in drinking water is an important assessment for quality as well as for the detection of pipeline corrosion. The aim of this research was to develop a simple, low cost, and accurate method based on cloud point extraction for the preconcentration and determination of iron, lead, and cadmium by flame atomic absorption spectrometry (FAAS) when the metal concentration in the sample is below the limit of detection without enrichment. By utilizing both 2,4-diamino-6-phenyl-1,3,5-triazine (DPT) and 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) as chelating agents, and using Triton X-114 as the surfactant, lead, cadmium, and iron were concentrated in water samples prior to determination. The preconcentration was optimized by varying experimental factors, including the temperature, pH, and the concentrations of the chelating agents and surfactant. Using the optimized conditions, this novel procedure allows the determination of these trace elements with a 20-fold reduction in the detection limit with recoveries as high as 99%. The good reproducibility of the results demonstrates that this method was successfully applied to the determination of iron, lead, and cadmium in water samples by FAAS.