Recovery of polycyclic aromatic hydrocarbons and their oxygenated derivatives in contaminated soils using aminopropyl silica solid phase extraction

Abstract

The formation, fate, and toxicology of oxy-, hydroxy-, and carboxy-substituted PAH (OPAH, OHPAH, COOHPAH, respectively) alongside PAH in contaminated soils have received increasing attention over the past two decades; however, there are still to date no standardized methods available for their identification and quantitation in soil. Here we investigated and developed the first method using aminopropylsilica solid phase extraction (SPE) for these compounds. We further investigated the efficacy of the developed method for three soils representing a range of contamination levels and soil textural characteristics and evaluated the impact of different sample preparation steps on the recovery of targeted compounds. Average recovery of PAH, OPAH, and OHPAH standards were 99%, 84%, and 86%, respectively for the SPE method. In contrast, COOHPAH exhibited the lowest recovery (0-82%) and poor inter-batch reproducibility.Soil texture and contamination levels influenced full method efficiency. Specifically, soils with higher proportion of clay contributed to the loss of the higher molecular weight OHPAH prior to SPE. Soil with the highest contamination showed enhanced recovery of some lower-concentration mid weight PAH and OPAH, while the least contaminated soil showed greater sensitivity to evaporative losses during sample preparation.Recommendations for reducing matrix effects as well as the practice of using deuterated PAH surrogate standards for OPAH analysis are further discussed. Quantitation of recovered PAH and oxygenated PAH across the three soils showed high reproducibility (<10% relative standard deviation for a majority of compounds), supporting the use of this method for PAH, OPAH, and OHPAH at contaminated sites.

Solid‐phase adsorption methodologies of naturally occurring anthraquinones: A review

“…Most of the listed solids in fact showed a very good pattern of selectivity in extraction of such molecules as well as good values as regards the extractive yields. Indeed, several other sorbents have been applied for the extraction of synthetic anthraquinones and/or naturally occurring ones from biological matrices different from plant ones; these include, among the main explicative examples, mango seed powder, used for the extraction of Acid Blue 80, Acid Blue 324, Acid Green 25, and Acid Green 27 from aqueous solutions, 50 bis(tetraoxacalix[2]arene[2]triazine) modified silica, for the extraction of aloe‐emodin, emodin, physcion, chrysophanol, and rhein from human urine samples, 51 fly ash for the removal of Acid Blue 127 from aqueous solutions, 52 aminopropyl silica for the extraction of 9,10‐anthraquinone from contaminated soil, 53 and finally covalent organic polymers for the quantification of this same sample in environmental water 54 . All these are examples of the extreme versatility of synthesis and functionalization of solid materials to be employed in SPE, and their use in the extraction, pre‐concentration, and enrichment of naturally occurring anthraquinones is an attractive and interesting research topic for the near future.…”