Quick and Green Procedure for the Quantification of Chromium in an Anionic Surfactant System

Abstract

This study aims to establish a facile, user-friendly, accurate, and repeatable spectrophotometric detection method for Cr(III) ions in trace quantities. The method utilises reagent 1-nitroso-2-naphthol (NNPh) in a sodium dodecyl sulphate (SDS) 1.0 % micellar solution, replacing the old, time-consuming, and expensive solvent extraction method that employs hazardous solvents such as carbon tetrachloride and chloroform. SDS surfactant is used to solubilise indissoluble chelates, making the proposed technique easy, rapid, and environmentally friendly. The established method exhibits an improved linear calibration range, sensitivity, limit of detection, and selectivity compared to earlier spectrophotometric methods employing different complexing agents. The stoichiometric ratio between Cr and NNP was observed to be 1 : 3. The molar absorption coefficient (ε) was determined to be 2.05 ∙ 104 l mol−1 cm−1 at λmax 579 nm. The limits of detection for Cr(III) was measured as 3.49 ng l−1. A calibration linear curve was achieved in the concentration range of 0.5–5.0 μg ml−1. Results obtained showed good comparison with the results obtained by atomic absorption spectrometry. The developed method has been adapted for the analysis of Cr(III) in various alloys, pharmaceutical, environmental, and biological samples.

Keywords

• chromium
• micellar solution
• 1-nitroso-2-naphthol
• spectrophotometry
• sodium dodecyl sulphate