Automatic Searching and Evaluation of Priority and Emerging Contaminants in Wastewater and River Water by Stir Bar Sorptive Extraction followed by Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry

Abstract

A new analytical method based on stir bar sorptive extraction (SBSE), followed by comprehensive two-dimensional gas chromatography (GCxGC-TOF-MS), has been developed for the automatic searching and evaluation of nonpolar or semipolar contaminants in wastewater and river water. The target compounds selected were 13 personal care products (PCPs), 15 polycyclic aromatic hydrocarbons (PAHs) and 27 pesticides. Excellent results have been obtained in terms of separation efficiency and also in terms of compound identification. Exceptional method detection limits were achieved applying the optimized method, at or below 1 ng/L for most of the compounds in real samples. The reliable confirmation of analyte identity was possible at this low concentration level, even for typically troublesome compounds such as the PAHs. The other validation parameters were good. In addition to obtaining analytical information such as identification and quantification of target analytes, it is also possible to screen for nontarget compounds or unknowns. New contaminants have been identified in the wastewater effluents and river water samples, such as cholesterol and its degradation products, pharmaceuticals, industrial products, other pesticides, and PCPs. The multidimensional information generated by the instrument can also be used by the researchers for contrasting samples and identifying, much more easily, the major differences between samples. We have used this feature to propose studies of comparison between the fingerprinting of different water samples, such as the contamination variation along a river affected by the discharge of urban wastewaters and also the contamination variation over a period of time in the effluent. Results show that the most frequently detected contaminants (and the contaminants detected at higher concentrations) were the PCPs. The musk fragrances galaxolide and tonalid were the most concentrated compounds in the samples. The pesticides and PAHs were present at much lower concentration than PCPs.

Triclosan breakdown by Fenton-like oxidation

“…To learn more on the potential oxidation byproducts, the samples from reaction were analyzed by SBSE-GC Â GC-TOF-MS, a powerful tool for the automatic screening, identification and quantification of priority and emerging organic micropollutants developed by Gómez et al [31]. It is a novel analytical method based on stir bar sorptive extraction (SBSE) followed by comprehensive two-dimensional gas chromatography (GC Â GC-TOF-MS).…”

Improved wet peroxide oxidation strategies for the treatment of chlorophenols

“…The wastewater from those industries commonly contains chlorophenols in significant amounts, and they have been detected in both surface and ground waters [1][2][3][4]. This fact involves a significant risk for the environment due to the high toxicity, persistence and low biodegradability of these compounds which have been listed as priority pollutants by the European Decision 2455/2001/ EC and by the US EPA in the Clean Water Act.…”

Atmospheric pressure gas chromatography–time-of-flight-mass spectrometry (APGC–ToF-MS) for the determination of regulated and emerging contaminants in aqueous samples after stir bar sorptive extraction (SBSE)

“…number of rings (e.g., dibenzo[a,h]anthracene), PCBs with many chlorine atoms (e.g., PCB 138), pyrethroids, and some UV-filters, all of them showing higher recovery percentages in the absence of NaCl. This effect could be partly counteracted by the addition of an organic solvent (methanol), which was also intended to minimize the possible adsorption of more hydrophobic compounds onto the glass walls of the flasks [1,16]. Thus, a positive response was observed for some compounds such as metoxichlor, 4,4-DDD, carbophenothion and musk ketone, although the effect was not dramatic (<30%) as most of these chemicals already have high affinity for the stir bars rather than for the glass walls.…”

“…Thousands of different organic compounds are discharged into aquatic systems every day from point (e.g., urban and industrial wastewater discharges) [1] and diffuse pollution sources (e.g., use of fertilizers in agriculture or atmospheric deposition of pollutants from vehicles and factories) [2]. So far, only a few of these contaminants have been studied in detail and regulated based on their well-known toxicity and/or other negative environmental impacts (Stockholm Convention on Persistent Organic Pollutants, 1991) [3].…”