Determination of trace amounts of chromium ions in water and food samples using ligand-less solid phase extraction-based modified nanoboehmite

Chromium is one of the hazardous pollutants in industrial effluents. In this study, a new nano-boehmite modified with sodium dodecyl sulphate is developed for preconcentration trace amounts of chromium ions as a prior step to its determination by flame atomic absorption spectrometry. We investigated the effect of various parameters on the recovery of the analyte ions, including pH of sample solution, amount of sorbent, sample volume on extraction efficiency of the chromium ions. Under the best experimental conditions, the calibration curve was linear in the range of 1.0 -700.0 ng.mL^-1 of chromium with R² = 0.997. Detection limit was 0.6 ng.mL^-1 in the original solution (3Sb/m) and the relative standard deviation for seven replicate determination of 0.5 μg.mL^-1 chromium was ±2.4%. The developed method was successfully applied to the extraction and determination of chromium in water and food samples with satisfactory results.