Green analytical approach for multielemental determination in oily matrices combining extraction induced by emulsion breaking (EIEB) with ICP OES

The development of methods aligned with the principles of Green Analytical Chemistry (GAC) has become imperative. Extraction induced by emulsion breaking (EIEB) combined with multielemental techniques offers several advantages, including reduced consumption of hazardous reagents, multielemental analysis capability, high throughput, operational simplicity, time efficiency, and low energy demand. In this context, the aim of this work was to develop an analytical method for the determination of Cd, Cr, Cu, Ni, Ti, and V in oily matrices by combining EIEB with inductively coupled plasma optical emission spectrometry (ICP OES). Emulsion formation was evaluated in different media, and emulsion breaking was investigated using heating, centrifugation, and the addition of HNO3 or ultrapure water. Based on the experimental results, the selected conditions were an extraction solution containing TX-114 (2% w/v) and HNO3 (3% v/v), vortex agitation for 60 s, and emulsion breaking by heating at 90 °C for 15 min. Calibration curves were obtained in the range of 20-250 µg kg-1, with detection limits ranging from 0.20 to 0.80 µg kg-1 and quantification limits ranging from 0.6 to 2.5 µg kg-1. The proposed method was applied to several oil-based matrices from different sources, including mineral oil, lavender, lemon, and clove essential oils, a biodiesel reference material, and edible oil samples. The application of metrics based on the principles of GAC and White Analytical Chemistry (WAC) allowed a comprehensive assessment of the method in terms of environmental impact, sustainability, analytical performance, and applicability. Owing to its simplicity, low reagent consumption, and cost-effectiveness, the method can be readily adapted for routine analysis. The results of the GAC and WAC evaluations confirmed that the developed method complies with the principles of both approaches.