Selective and sensitive spectrophotometric method for determination of sub-micro-molar amounts of aluminium ion

A simple and accurate spectrophotometric method for determination of trace and ultra-trace amounts of Al3+ ion in tap and wastewater sample has been described. Using the eriochrome cyanine R (ECR) in the presence of N,N-dodecyltrimethylammonium bromide (DTAB) as cationic surfactant spectrophotometric determination of Al3+ ion has been carried out. The Beer's law is obeyed over the concentration range of 4-400 ng mL−1 of Al3+ ion with the detection limits of 0.14 ng mL−1, while the molar absorptivity of complexes is 1.19 × 105 L mol−1 cm−1. The influence of type and amount of surfactant, pH, and amount of ligand on sensitivity of spectrophotometric method were optimized. The method has been successfully applied for Al3+ ion determination in real sample.