Screening of Environmental Contaminants Using GC/Q-TOF and Accurate Mass Library

Oral Presentation

Prepared by K. Chen1, P. Wylie2, T. Young3
1 - Agilent Technologies, 5301 Stevens Creek Blvd, Santa Clara, CA, 95051, United States
2 - Agilent Technologies, Inc., 2850 Centerville Rd, Wilmington, DE, 19808, United States
3 - Department of Civil and Environmental Engineering, University of California, 3113 Ghausi Hall, One Shields Avenue, Davis, CA, 95616, United States


Contact Information: kai_chen@agilent.com; 408-553-7743


ABSTRACT

The investigation of organic micropollutants is an important aspect of assessing environmental quality. Conventional monitoring approaches focus on analyzing a defined number of target compounds when a mass spectrometer is used, with the instrument operated in selected data acquisition mode for those targeted analytes. However, scientific studies have shown that such an approach may significantly underestimate the exposure and risk of pollutants, compared to a more comprehensive screening.

With recent advances in mass spectrometry, the scope of analysis is no longer limited by data acquisition owing to the sensitivity and selectivity provided by high resolution accurate mass instruments operated in full spectrum acquisition mode. Accurate mass information enhances the confidence of compound identification. Retrospective data mining also becomes possible for researchers when an emerging contaminant is discovered. Therefore, there is growing interest in broad scope screening of organic micropollutants by using high resolution mass spectrometry coupled to both LC and GC. Consequently, efficient conversion of mass spectrometric data into knowledge regarding the presence of micropollutants is also highly desirable.

In this work, an accurate mass EI GC/MS spectral library has been developed for GC/Q-TOF to facilitate data processing for suspect screening. The library contains the spectra and retention times for around 1000 compounds including pesticides, PAHs, phthalates, halogenated aromatics and other environmental pollutants. It allows users to set up a screening method for a broad suite of suspect pollutants without the need for reference standards. Several environmental samples were analyzed by an Agilent 7250 GC/Q-TOF system with a method retention time locked to the library reference values. We will describe how the library facilitated the identification of a diverse group of micropollutants.