Enhanced extraction of arsenic and cadmium from environmental samples using a natural deep eutectic solvent and determination by inductively coupled plasma mass spectrometry

ABSTRACT

A natural deep eutectic solvent (NADES) synthesised from malic acid, xylitol, and water was used as a solvent in ultrasound-assisted extraction (UAE) for the determination of As and Cd in fish and shellfish samples by inductively coupled plasma mass spectrometry. The formation of the solvent was confirmed by infrared spectroscopy analysis, which showed the presence of hydrogen bonds between the components. Evaluation was made of elemental determinations performed using standard and kinetic energy discrimination (KED) modes. Higher sensitivity was observed using KED mode, which could be attributed to charge transfer between carbon and the analytes when the NADES introduced into the plasma. The detection limits were 12.7 and 0.100 µg kg⁻¹ for As and Cd, respectively, and the accuracy of the extraction procedure was assessed by comparing methods. The Cd concentrations in the fish and shellfish samples were below the limits of quantification, while the As concentrations varied between 1.88 and 12.0 µg g⁻¹, exceeding the maximum values recommended by regulatory agencies.

KEYWORDS:

• Green solvents
• natural deep eutectic solvent
• ultrasound-assisted extraction
• plasma-based technique

Acknowledgments

The authors would like to thank Coordination for the Improvement of Higher Education Personnel – Brazil (CAPES) – Finance Code 001 and process number 88887136426/2017/00, National Council for Scientific and Technological Development (CNPq) for fellowships (processes number 465571/2014-0, 421694/2018-1, and 306698/2019-6), and São Paulo Research Foundation (FAPESP,  processes number 2014/50945-4, 2015/08873-9, 2017/18531-3, and 2019/22113-8) for the financial support, and National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM).

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by the National Council for Scientific and Technological Development (CNPq – processes number 465571/2014-0, 421694/2018-1, and 306698/2019-6), São Paulo Research Foundation (FAPESP – processes number 2014/50945-4 , 2015/08873-9, 2017/18531-3, and 2019/22113-8), and Coordination for the Improvement of Higher Education Personnel (CAPES – Finance Code 001 and process CAPES 88887136426/2017/00).