Essential oils are widely used in the industry, being particularly important in the manufacturing of cosmetics. Since the use of cosmetic products has grown exponentially in recent years, it is of great relevance to control elemental impurities in these products, as they may have potentially adverse effects on human health [1, 2]. For this purpose, a straightforward, highly sensitive, and matrix effect free analytical method has been developed for the simultaneous determination of trace metals in essential oils, employing inductively coupled plasma optical emission spectrometry (ICP OES). To eliminate potential interferences from the matrix and to enhance the sensitivity of the analysis, a dispersive liquid-liquid microextraction (DLLME) has been carried out using a magnetic deep eutectic solvent (MDES) as an extractant phase. The primary benefit of this solvent is its capacity to be separated from the sample by applying an external magnetic field, thereby circumventing the necessity of a centrifugation step and rendering the method simpler, faster, and more environmentally friendly in comparison with the use of conventional DES. The main experimental factors influencing the DLLME have been optimized using multivariate analysis. Additionally, the trueness of the method has been evaluated through recovery experiments in commercial essential oils.

Acknowledgements

The authors are grateful to the Spanish Ministry of Science and Innovation (PID2021-126155OB-I00), to the Regional Government of Valencia (Spain) (CIPROM/2021/062, INVEST/2022/70) and to the European Commission and the Bulgarian Ministry of Education and Science (BG-RRP-2.004.0001-C01) for the financial support. The authors are also grateful to the Spanish Ministry of Science and Innovation for granting the Spanish Network of Excellence in Sample Preparation (RED2022-134079-T).

References

[1] L. Abad-Gil; S. Lucas-Sánchez; M. J. Gismera; M. T. Sevilla; J. R. Procopio Microchemical Journal, 2022, 182, 107881.

[2] M. Irfan; A. Shafeeq; U. Siddiq; F. Bashir; T. Ahmad; M. Athar; M. T. Butt; S. Ullah; A. Mukhtar; M. Hussien; S. S. Lam Journal of Hazardous Materials, 2022, 433, 128806.