Low Flow, High Gains—Using Microflow LC Techniques for Environmental Applications

Optimizing Laboratory Operations
Poster Presentation

Prepared by K. Adams, K. Oetjen, D. Tran, C. Butt, C. Borton
SCIEX, 500 Old Connecticut Path, Building B, Framingham, MA, 01701, United States


Contact Information: [email protected]; 978-938-9253

ABSTRACT

Liquid chromatography (LC) has been applied to a wide range of environmental samples and combining this with tandem mass spectrometry (MS/MS) allows for highly sensitive and accurate measurements. A large majority of LC-MS/MS methods rely on electron spray ionization (ESI), which is susceptible to matrix effects, including ion suppression. However, the versatility of ESI and the wide range of compounds of environmental concern that can be analyzed using this method have made LC-MS/MS an important tool for environmental research and monitoring. As LC-MS/MS becomes a more important tool for the analysis of nonvolatile and polar contaminants, research has focused on creating more sensitive methods. Microflow LC has been shown to achieve sensitivity gains but until recently has primarily been used for peptide LC-MS/MS quantification. Microflow LC operates at significantly lower flow rates (up to 100x lower) compared to traditional analytical high-performance LC systems. These systems operate at flow rates in the range 1–200 μL/min and the droplets created have a diameter of only a few microns; generating more ions and minimizing ion suppression effects. This could be extremely valuable for environmental matrices which are notoriously complex, even after extensive sample extraction techniques. Here, a comparison of microflow LC and analytical flow LC for the analysis of 69 frequently analyzed pesticides was performed. Both methods use the same SCIEX QTRAP 6500+ LC-MS/MS System. Sensitivity gains of up to 240x were observed for selected pesticides. The sensitivity gains from microflow LC compared to analytical flow LC enabled simpler sample preparation procedures without sacrificing limits of quantitation (LOQs) while also reducing solvent consumption for better sustainability.