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Ensuring the safety of the world’s drinking water supply is critically important. The health of the world’s lakes, rivers, streams and oceans can be impacted by human and natural activities, and monitoring of these resources is of increasing concern worldwide. Screening water samples for targeted contaminants, such as pesticides, herbicides, and other pollutants, followed by quantification of these contaminants, is one possible experiment. Screening water samples for unknown contaminants is another possible experiment and is one of the most challenging workflows in the laboratory, requiring a different experimental and data analysis approach. High-resolution, accurate-mass (HR/AM) mass spectrometry is ideally suited for this difficult analysis. With the high-resolution capabilities and fast scanning speed of Orbitrap™-based platforms, screening water for hundreds of contaminants can be performed in less time than ever before. Results can be delivered quickly, and the safety of our water can be ensured.
For additional resources, search the Orbitrap Science Library
Overview
Workflow Overview for Unknown Environmental Contaminant Screening & Quantification
For unknown screening of water samples, the goal is to identify as many of the compounds present in the particular sample as possible. This is a more difficult experiment because there is not a targeted list of compounds. In a typical workflow, the samples are collected and then shipped to the laboratory for analysis. After the samples arrive, they are logged, processed, and extracted. They are then analyzed on the mass spectrometer, and the data is scrutinized using automated software. The results can be checked against a local database or a larger external database and further confirmed.
Resources
Gerssen A, Mulder PP, et al.
Anal Chim Acta. 2011 Jan 31;685(2):176-85.
Calza P, Medana C, et al.
Rapid Commun Mass Spectrom. 2012 Aug 15;26(15):1687-704.

Mol HG, Zomer P, et al.
Anal Bioanal Chem. 2012 Jul;403(10):2891-908.
Workflow Overview for Unknown Screening of Environmental Contaminants
For unknown screening of water samples, the goal is to identify as many of the compounds present in the particular sample as possible. This is a more difficult experiment because there is not a targeted list of compounds. In a typical workflow, the samples are collected and then shipped to the laboratory for analysis. After the samples arrive, they are logged, processed, and extracted. They are then analyzed on the mass spectrometer, and the data is scrutinized using automated software. The results can be checked against a local database or a larger external database and further confirmed.
Resources
Gerssen A, Mulder PP, et al.
Anal Chim Acta. 2011 Jan 31;685(2):176-85.
Calza P, Medana C, et al.
Rapid Commun Mass Spectrom. 2012 Aug 15;26(15):1687-704.

Mol HG, Zomer P, et al.
Anal Bioanal Chem. 2012 Jul;403(10):2891-908.
Sample Preparation
Sample Preparation Workflow for Unknown Screening of Environmental Contaminants
Due to the complexity of the regulations for environmental testing around the world, many different sample preparation techniques are utilized. For example, automated, solid-phase extraction can be performed using the Thermo Scientific Dionex AutoTrace system, or online pre-concentration and cleanup can be performed with the Thermo Scientific EQuan MAX system. Offline SPE is also utilized.
Mass Spectrometry
Mass Spectrometry Workflow for Unknown Screening of Environmental Contaminants
The use of UHPLC in environmental analysis has been growing steadily to decrease the turnaround analysis time per sample. Advances in Orbitrap™ technology have been made to accommodate the requirements associated with UHPLC, namely, HR/AM and high speed.
With these benefits in mind, here are a few highlights that will help you acquire the unknown and screening data in which you are most interested. Our full-scan, data-dependant MS/MS methods enable screening for unknown contaminants:
- The system rapidly and automatically performs MS/MS on the components detected in the MS spectrum with high resolution and accurate mass at a speed amenable to UHPLC.
- After data is acquired and components are identified, the data can always be re-interrogated for new compounds of interest.
- Full-scan MS and MS/MS allows confirmation of identity in the same run.
Products
Thermo Scientific Accela High Speed LC
Download the brochure
Thermo Scientific Dionex UltiMate 3000 HPLC series
Thermo Scientific EQuan MAX high throughput LC-MS solution
Download the brochure
Resources
Gerssen A, Mulder PP, et al.
Anal Chim Acta. 2011 Jan 31;685(2):176-85.
Calza P, Medana C, et al.
Rapid Commun Mass Spectrom. 2012 Aug 15;26(15):1687-704.

Mol HG, Zomer P, et al.
Anal Bioanal Chem. 2012 Jul;403(10):2891-908.
Data Analysis
Data Analysis Workflow for Unknown Screening of Environmental Contaminants
Multiple software solutions are available for the analysis of data from unknown screening of environmental samples.
Thermo Scientific ExactFinder software is the preferred software for unknown contaminant screening. ExactFinder™ software has the ability to select ion peaks of interest from the full MS spectra, assign a theoretical molecular formula based on m/z, and search ChemSpider for identification of potential candidates.
After a putative identification of the contaminant has been made, Thermo Scientific Mass Frontier software can be used for identity confirmation by using the fragment ion spectrum acquired in the data-dependent MS/MS run. The software also has the ability to show chemical synthesis breakdown patterns.
For the ultimate in unknown screening, experiments can be performed in which two samples are compared to one another. For example, a known clean drinking water sample can be compared to a “suspect” drinking water sample. Using Thermo Scientific SIEVE software, the two different samples can be compared to one another. SIEVE™ software references the two samples and offers a “fingerprint” of the differences between the two samples, thus allowing the scientist to focus on what is different between the two.
Products
Thermo Scientific TraceFinder Software
Download the brochure
Thermo Scientific ExactFinder Software
Download the brochure
Mass Frontier Spectral Interpretation Software
Download the brochure
Sieve Differential Expression Software
Download the brochure
Resources
Gerssen A, Mulder PP, et al.
Anal Chim Acta. 2011 Jan 31;685(2):176-85.
Calza P, Medana C, et al.
Rapid Commun Mass Spectrom. 2012 Aug 15;26(15):1687-704.

Mol HG, Zomer P, et al.
Anal Bioanal Chem. 2012 Jul;403(10):2891-908.
Thermo Fisher Scientific
United States
