New Dispersive Solid Phase Extraction Method Developed for Phenolic Compounds

Scientists from the Tabriz University of Medical Sciences in Tabriz, Iran recently developed a new dispersive solid phase extraction (DSPE) method for extracting phenolic compounds from aqueous samples. Their findings were published in Analytica Chimica Acta (1).

Modern urban wastewater treatment plant. Water purification is the process of removing undesirable chemicals, suspended solids and gases from contaminated water. Water cleaning facility outdoors. | Image Credit: © arhendrix - stock.adobe.com

Phenolic compounds are environmental pollutants that are produced by industrial activities. These compounds can be formed in several ways. For example, obtaining metallurgical coke from coal, or converting coal to liquid or gas fuels, which often occurs in oil refineries. These compounds, which can be persistent in water and have relatively long half-lives, can enter the environment by the discharging of large amounts of oil refinery waste. Phenolic compounds can be harmful to organisms through long-term exposure, and high dosages can lead to nervous system disruptions. This has led to regulations meant to name maximum residue limits (MRLs) for phenols in water samples.

As part of this study, the scientists hoped to introduce a new homogenous dispersive solid phase extraction (DSPE) approach for extracting phenolic compounds from aqueous samples and their analysis via gas chromatography coupled with a flame ionization detector (GC-FID). As part of this, they created a new extraction procedure based on in situ formation of carbon dioxide (CO2)-incorporated solid sorbent. In this system, a homogenous solution of the samples and diamine was prepared and placed under a CO2 stream. From there, CO2 molecules were incorporated into the diamine’s structure, forming a carbamic acid analogue of the diamine, which was insoluble in the solution. The obtained solid acted as a sorbent for analyte adsorption. According to the scientists, this is the first report where this method has been used in sample preparation.

Read More: In-Situ Formation of CO2-Incorportaed Solid Sorbent for Dispersive Solid Phase Extraction of Phenolic Compounds from Water and Wastewater Samples Prior to Gas Chromatography-Flame Ionization Detector

For this experiment, the sample solution was mixed with isophorone diamine and placed under a CO2 stream; this led to a reaction that produced a carbamic acid analogue. This was then dispersed into the sample solution as tiny particles, which adsorbed the analytes that were later eluted by a volatile organic solvent and concentrated more by eluate vaporization. Extraction was performed at low temperatures to limit releasing carbon dioxide from the produced compound. To obtain reliable results, the method was validated, with the obtained limits of detection and quantification ranging from 0.29–0.41 and 0.96–1.3 ng/mL, respectively. Acceptable relative standard deviation (≤7.3%) and coefficient of determination (≥0.994) values confirmed the repeatability and linearity of the method.Further, the method displayed high enrichment factors (410–435) and extraction recoveries (82–87%).

Reference

(1) Mardani, A.; Farajzadeh, M. A.; Nemati, M.; Mogaddam, M. R. A. In-Situ Formation of CO2-Incorportaed Solid Sorbent for Dispersive Solid Phase Extraction of Phenolic Compounds from Water and Wastewater Samples Prior to Gas Chromatography-Flame Ionization Detector. Anal. Chim. Acta 2024, 1287, 342062. DOI: https://doi.org/10.1016/j.aca.2023.342062