Identification of polypropylene glycols and polyethylene glycol carboxylates in flowback and produced water from hydraulic fracturing

E Michael Thurman; Imma Ferrer; James Rosenblum; Karl Linden; Joseph N Ryan

doi:10.1016/j.jhazmat.2016.02.041

Identification of polypropylene glycols and polyethylene glycol carboxylates in flowback and produced water from hydraulic fracturing

J Hazard Mater. 2017 Feb 5;323(Pt A):11-17. doi: 10.1016/j.jhazmat.2016.02.041. Epub 2016 Feb 23.

Authors

E Michael Thurman¹, Imma Ferrer², James Rosenblum³, Karl Linden⁴, Joseph N Ryan⁵

Affiliations

¹ Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80303 USA. Electronic address: michael.thurman@colorado.edu.
² Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80303 USA. Electronic address: imma.ferrer@colorado.edu.
³ Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80303 USA. Electronic address: james.rosenblum@colorado.edu.
⁴ Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80303 USA. Electronic address: karl.linden@colorado.edu.
⁵ Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80303 USA. Electronic address: joseph.ryan@colorado.edu.

PMID: 26947804
DOI: 10.1016/j.jhazmat.2016.02.041

Abstract

The purpose of the study was to separate and identify the unknown surfactants present in flowback and produced water from oil and gas wells in the Denver-Julesburg Basin (Niobrara Formation) in Weld County, Colorado, USA. Weld County has been drilled extensively during the last five years for oil and gas between 7000-8000 feet below land-surface. Polypropylene glycols (PPGs) and polyethylene glycols carboxylates (PEG-Cs) were found for the first time in these flowback and produced water samples. These ethoxylated surfactants may be used as friction reducers, clay stabilizers, and surfactants. Ultrahigh-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC/QTOF-MS) was used to separate and identify the different classes of PPGs, PEG-Cs, and their isomers. The Kendrick mass scale was applied along with mass spectrometry/mass spectrometry (MS-MS) with accurate mass for rapid and unequivocal identification. The PPGs and their isomers occur at the ppm concentration range and may be useful as "fingerprints" of hydraulic-fracturing. Comparing these detections to the compounds used in the fracturing process from FracFocus 3.0 (https://fracfocus.org), it appears that both PPGs and polyethylene glycols (PEGs) are commonly named as additives, but the PEG-Cs have not been reported. The PEG-Cs may be trace impurities or degradation products of PEGs.

Keywords: Accurate mass; Hydraulic fracturing; LC/QTOF-MS; Polypropylene glycols.