Developed a modified liquid–liquid micro-extraction method for the preconcentration of cadmium in groundwater samples of aquifers at different depth in a coal mining area

ABSTRACT

A novel, speedy and modified ultrasonic-assisted dual dispersive liquid–liquid microextraction (UDDLLμE) method using a green deep eutectic solvent (DES) for the enrichment and preconcentration of cadmium (Cd²⁺) in water samples of ground water/aquifers of Thar coalfield, Pakistan was developed. The ammonium pyrrolidine dithiocarbamate (APDC) complexed with Cd²⁺ from aqueous solution and hydrophobic complex was extracted in DES. The efficiency of the developed method was checked by comparing with conventional LLμE method. For dual stage/step, the Cd²⁺ complex entrapped in DES was back-extracted into the acidic solution, then analysed by flame atomic absorption spectrometry. The several analytical factors like pH, amount of DES, concentrations of APDC and sonication time were optimised. The preconcentration factor and the limit of detection were observed for proposed method as 78.2 and 0.046 μg L⁻¹, respectively. A matrix matched certified reference material of water (1643e), was analysed to verify the certainty of the proposed method. The proposed method was successfully applied for the preconcentration of Cd²⁺ from aquifer water samples of Thar coalfield, Pakistan. The experimental result indicated that the concentration of Cd²⁺ in water samples of aquifers were above than suggested limit of World Health Organization (WHO).

KEYWORDS:

• Ultrasound energy
• deep eutectic solvent
• microextraction
• cadmium
• aquifers

Acknowledgments

The authors would like to thank National Centre of Excellence in Analytical Chemistry (NCEAC) University of Sindh Jamshoro for providing financial support and excellent research lab facilities for scholars to carryout research work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was not funded by any funding agency.