Activated Carbon Modified with Sodium Dodecyl Sulfonate as a Solid Phase Sorbent for the Separation and Preconcentration of Trace Cadmium in Water Samples with Detection by Electrothermal Atomic Absorption Spectrometry

Abstract

A novel absorbent was prepared by sodium dodecyl sulfonate (SDS)-modified activated carbon (SDS-AC) and was employed as the microcolumn packing material for separation/preconcentration of trace Cd(II). The method based on Cd(II) was quantitatively retained by SDS-AC sorbent, which entailed cation exchange nature and negative charged surface, facilitating favorable retention of positively charged ions. The retained Cd(II) was effectively recovered with elution by 1 mol · L⁻¹ HNO₃, and the eluent was quantified by electrothermal atomic absorption spectrometry (ET-AAS). Under the optimized conditions, the limit of detection (LOD) for Cd(II) was 3 ng · L⁻¹ with the consumption of 20.0 mL sample solution. The relative standard deviation (RSD) for ten replicate measurements of 50 ng · L⁻¹ Cd(II) was 2.9%. The developed technique was demonstrated for the determination of trace Cd(II) in water samples and the recoveries for spiked samples were found to be in the range of 94.9–107.2%. For validation, two certified reference materials of water samples (GBW08607 and GBW08608) were analyzed, and the results obtained were in good agreement with the certified values.

Keywords:

• Cadmium determination
• Electrothermal atomic absorption spectrometry
• Modified activated carbon
• Sodium dodecyl sulfonate
• Water samples

Acknowledgments

Financial support from the National Natural Science Foundation of China (No. 41003015), the Natural Science Foundation of the Education Department of Henan Province (No. 2011B150010), and the Natural Science Foundation of Henan Polytechnic University (No. B2008-26 and YB016) is gratefully acknowledged.

Notes

MSPE: magnetic solid phase extraction.

“++++” means “the most expensive.”.

“+++” means “more expensive.”.

“++” means “expensive.”.

“+” means “normal.”.