Application of experimental design for dispersive liquid-liquid microextraction optimization for metallic impurities determination in arnica infusion employing green solvents

Author(s)

Grecco, Giulia Brick ; Albini, Kathleen Fioramonte ; Longo Jr, Luiz Sidney ; Andreo, Marcio Adriano ; Batista, Bruno Lemos ; Lourenco, Felipe Rebello ; Calixto, Leandro Augusto

• Document type: Journal article
• Source: Journal of the Iranian Chemical Society; v. N/A, p. 10-pg., 2022-10-08.

Abstract

Arnicas Solidago microglossa DC. and Arnica montana L. are easily-accessible plants used as natural medicines by the Brazilian population. These products are susceptible to contamination by elemental impurities that are harmful to the human health. In 2017, the United States Pharmacopeia (USP) published two new chapters for elemental impurities determination. The classical methods were replaced by advanced analytical techniques such as optical emission spectrometry and inductively coupled plasma mass spectrometry (ICP OES and ICP-MS, respectively). However, these are expensive and difficult techniques to implement in small laboratories. Dispersive liquid-liquid microextraction (DLLME) contributes to improve the limit of quantification (LOQ), allowing the use of alternative analytical techniques to ICP such as capillary electrophoresis, atomic absorption and UV-Vis spectrophotometry. This work described the use a design of experiment (DoE) for the optimization of DLLME applied to the determination of metallic impurities in arnica infusions. The replacement of toxic solvents (i.e. chloroform and methanol) for a combination of organic carbonates and ionic liquids, proved to be a promising green alternative as solvent mixture in DLLME technique. The enrichment factor in infusion was between 89 and 127. The method was validated by evaluating the following parameters: selectivity, linearity, precision, accuracy, limit of detection (LOD) and LOQ. The defined range was 5.0-100.0 mu g L-1 for cadmium and lead, and 1.5-30.0 mu g L-1 for mercury, with accuracy varying from 94 to 107% and RSD from 1.77 to 8.51%. Therefore, DLLME employing green chemistry solvents has proved to be applicable for the analysis of elemental impurities in infusions. (AU)

• FAPESP's process: 16/25256-6 - Determination of heavy metals in traditional herbal medicines by alternative analytical techniques employing green chemistry principles
• Grantee: Leandro Augusto Calixto
• Support Opportunities: Regular Research Grants