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allow the largest breadth of PPCPs in one LC-MS/MS run. Metformin was the clearest example. Despite many approaches, no satisfactory reverse-phase LC method could be discovered because of its high polarity. Therefore, as described in EPA Method 1694, hydrophilic interaction liquid chromatography (HILIC) was used for the successful LC separation of metformin in water. Again, pH had a dramatic effect on the response of metformin (and other Group 4 PPCPs). The best response for metformin was with the water sample adjusted to pH 11.3 prior to injection on the reverse-phase EQuan trapping column.
Conclusion
Despite all of the challenges in the development of one single LC/MS method for this diverse group of compounds, a balance was found that allowed the measurement of the 67 PPCPs in water by the Thermo Scientific EQuan system with a large majority being quantified at or below 10 ng/L using a 0.5 mL injection volume with detection on the triple stage quadrupole TSQ Vantage™ mass spectrometer. The best
Figure 6. (a,b,c). Example chromatograms of the PPCPs in water at the ng/L level. The LLOQ for each compound is listed in parentheses.
compromise for the online sample preparation method was to run an acidified and a basified water sample containing 10% ACN. Figure 6 shows example chromatograms for the PPCPs in water at the ng/L level using this approach. The red chromatograms were the water samples at pH 2.0 and the blue chromatograms were
the water samples at pH 11.3. In general, basic conditions were preferable for analysing the smaller, more polar compounds and acidic preferable for analysing the larger, more lipophilic compounds. Use of this faster method will enable improved analysis of PPCPs and contribute to improving the environment.
New Metal Columns Provide Exceptional Performance in High-Throughput and High-Temperature Applications
Thermo Fisher Scientific introduce the Thermo Scientific TraceGOLD GC Metal Columns range of gas chromatography (GC) columns, setting a new benchmark in high-temperature performance. These robust, metal capillary columns are designed for higher temperature ranges than standard GC columns and can process highly active samples and analytes without incurring any damage. The new TraceGOLD™ GC Metal Columns are optimized for use in high-throughput analyses because they are resistant to the column breakdown and bleed that is often caused by repeated sample runs. Providing added flexibility for analysts with highly demanding applications, TraceGOLD GC Metal Columns deliver quality separations and excellent value. To accommodate a wide variety of analytical protocols, TraceGOLD GC Metal Columns are available in three stationary phase formats: TG-1MT, TG-5MT and TG-WAXMT, with a range of column lengths, internal diameters and film thicknesses. GC is a common technique used in the analysis of volatile and semi volatile compounds, and TraceGOLD GC Metal Columns are optimized to enhance analytical workflows, particularly for petrochemical, environmental, forensic science and food safety applications in which high sample volume or activity are common. Highly demanding workflows impose stresses on standard GC capillary columns, causing column bleed that leads to high background readings, peak spreading and tailing. The range of TraceGOLD GC Metal Columns withstands common stresses and prevents the column breakdown or column bleed that ultimately compromise the quality of separations.
For more information about the Thermo Fisher Scientific portfolio of TraceGOLD GC Metal Columns, please visit
www.thermoscientific.com/tracegold First Quadupole Time-of-Flight Gas Chromatography System Introduced
Agilent Technologies announce the launch of the 7200 Quadrupole Time-of-Flight gas chromatography/mass spectrometry (Q-TOF GC/MS) The Agilent 7200 is the world’s first Q-TOF GC/MS built specifically for GC that delivers a new level of chromatographic and spectral resolution to a wide range of biological and chemical GC/MS analyses. The instrument was showed in Singapore at an event for the first time, and generated a lot of interest from the conference attendees. Agilent’s 7200 Q-TOF GC/MS is well-suited for analyzing target compounds and unknowns in challenging applications such as metabolomics, food safety, natural products research, environmental analysis, sports-doping detection, and energy research. With the 7200 Q- TOF GC/MS, customers are able to coax more qualitative and quantitative information out of increasingly complex samples. Also at the event, Agilent introduced the 6550 iFunnel Quadrupole Time-of-Flight liquid chromatography mass spectrometry system (Q-TOF LC/MS). The 6550 iFunnel Q-TOF offers 10 times more sensitivity than its previous model, while delivering fast acquisition to 50 spectra/sec, up to five orders of intra-scan dynamic range, and robust performance and operation. The system is well suited for highly challenging, qualitative and quantitative analyses in applications such as metabolomics, food-safety screening, early-stage drug metabolism and pharmacokinetics, and protein identification.
For more information email
terry_sheehan@agilent.com
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