Purdue University Metabolite Profiling Facility further expands MS imaging with the SYNAPT XS

The Purdue University Metabolite Profiling Facility is an academic research laboratory whose scientists empower researchers with new technologies, methods development, sample analysis, expert training, and consultation.

To enhance their mass spectrometry (MS) imaging capability, the team were recently successful in achieving a National Institute of Health (NIH) S10 grant. The award enabled investment in a new, advanced MS instrument.

The team invested in Waters’ SYNAPT XS: a high-resolution mass spectrometry system equipped with DESI and MALDI imaging and ion mobility separation capabilities. This technology will lead the facility’s team through the next phase of their research in metabolite and lipid profiling.

We caught up with Director of the Facility, Dr. Bruce Cooper, and Research Scientist, Dr. Christina Ferreira, to discuss their research and challenges, and why they chose the SYNAPT XS.

Christina Ferreira
Bruce Cooper

What is your research focus and what trends are you observing?

Cooper: Our core MS-based facility at Purdue University focuses on metabolomic and lipidomic analysis. Across the hall is another group that focuses on proteomics, enabling us to collectively perform a broad range of -omics experiments. I have been the director of the facility since its creation 15 years ago and in that time there has been a significant increase in the demand for lipid analysis. Christina came aboard in 2016 to develop our lipidomics offerings.

Ferreira: My work is dedicated to discovery lipidomics utilizing fast and efficient methodologies. As lipids display great variation in their chemistry, there is not a single method that can detect them all. This is why we require fast exploratory methods that provide researchers with a comprehensive overview of the lipid content in their sample. Our colleagues and collaborators are often investigating disease biomarkers or attempting to predict characteristics such as infertility, and our facility helps them identify which lipids they should analyze further to aid their research.

What systems are you currently utilizing in your lab?

Cooper: The majority of our projects involve targeted analysis, where we identify and quantify defined groups of metabolites or lipids. For this work, we utilize four LC-triple quadrupoles and one GC-triple quadrupole instrument. Untargeted analysis requires higher resolution instrumentation and so we currently employ an LC-Q-ToF for discovery experiments. Recently, Christina advocated that we apply for a grant to install a state-of-the-art imaging instrument in the lab to expand our capabilities.

We compared results between our current MALDI imaging instrument and the SYNAPT XS as part of the grant submission process, and the difference in image quality was night and day“.

What is your selection process for choosing a mass spectrometer, and why did you favor the SYNAPT XS?

Cooper: An increasing number of the scientists who come to our facility are asking for advanced MS imaging. Desorption electrospray ionization (DESI) MS imaging began as a homegrown technology from Purdue University, but it is not offered as a service in any of the core facilities on campus! We wanted to change this, and we were looking for an instrument with DESI imaging capabilities. It was our plan for this platform to be utilized by all the major universities in the state of Indiana, including Purdue University, the University of Notre Dame, and Indiana University.

We also compared results between our current matrix-assisted laser desorption ionization (MALDI) imaging instrument and the SYNAPT XS as part of the grant submission process, and the difference in image quality was night and day. We submitted samples to the Waters demo lab, and the data from the SYNAPT XS became the backbone of the grant submission. The data highlighted the limitations of our current instrumentation and the benefits of adding a state-of-the-art instrument to our facility. This, alongside the additional DESI capability of the SYNAPT XS, will provide us with complete molecular coverage for metabolomics, lipidomics, and proteomics.

What are the biggest challenges you have come across in your recent research projects?

Ferreira: When we perform LC/MS experiments, the chromatography system does a lot of the heavy separation work before the molecules reach the mass spec’s ion source and eases the job of the mass spectrometer. With imaging experiments, it isn’t feasible to use chromatographic separation, and so the data acquired is inherently more complex than LC/MS data. This can be a major challenge!

Having a mass spec that includes ion mobility – a gas phase separation technique – is incredibly useful for imaging experiments. With the inclusion of ion mobility separation in the SYNAPT XS, we utilize the additional dimension of resolution to greatly enhance the discriminating power of our MS imaging experiments and can see things that would otherwise be impossible.

What do you love about your SYNAPT XS?

Ferreira: The ion mobility separation capabilities of the SYNAPT XS provide an extra dimension of resolution, allowing us to resolve complex lipid and metabolite classes that would otherwise be difficult to distinguish. This can help us to significantly reduce analysis time and comprehensively profile complex mixtures.

We are also excited by the potential of the SYNAPT XS to supply multi-modal imaging. Traditionally, the two ionization technologies have been seen as competitors, with MALDI most suited to large molecules including peptides and proteins, and DESI used for analyzing small molecules. In reality, they are complementary and as DESI is a non-destructive technology, the same tissue sample can be used for further analysis, such as MALDI imaging. By having two MS imaging technologies in one instrument, the SYNAPT XS is particularly irresistible for researchers.

Find out more about our flexible, all-in-one SYNAPT XS high resolution mass spectrometer here.

You can also discover the benefits of DESI imaging for direct tissue analysis here.