Modern LC/MS instruments are simpler to use than in the past, as well as highly sensitive compared with immunoassays. CLi spoke to Dr Jeff Zonderman, Director of Clinical and Toxicology LC/MS at Thermo Fisher Scientific, to discuss the advantages of LC/MS, and the ease with which the technique can be implemented into the work of a routine clinical diagnostic lab.
Q: Would you first explain very briefly, for any of our readers who may be unfamiliar with LC/MS, the processes that are actually involved in identifying and analysing organic samples using these techniques?
A: LC/MS is an acronym for a system that couples liquid chromatography technology with mass spectrometry technology; it’s a workflow that enables the technician to perform a series of separations on a sample and ultimately very selectively isolate, detect and quantitate the analyte(s) of interest.
The first step is the sample preparation phase, during which the analytes of interest are separated from the biological matrix, whether that is blood, urine, plasma, etc. There are many techniques used, and this is one area where Thermo Fisher Scientific has invested in technologies to make this step less labour-intensive and more economical. The second step is chromatography, during which the samples are run an LC column, which further separates the analytes based on their chemical properties (such as polarity to a c18 stationary phase). Finally, the mass spectrometry step separates the analytes based on their mass, so that eventually the mass spectrometer is used to detect the analytes of interest. Because the analyte of interest is ultimately being measured by mass, this is a more precise and selective method for performing these types
of applications.
To further increase the selectivity in this workflow, researchers have moved to LC-MS/MS, which enables the technician to isolate a fragment of the analyte of interest, and which is gaining acceptance for many clinical research and toxicology research applications. Detecting the analyte by measuring a fragment is actually a more selective method than trying to detect the entire analyte; the fragment has more unique characteristics, which provides a higher-confidence result. LC-MS/MS is one reason that mass spectrometry has a growing reputation for being much more sensitive and selective than other assay methods.
Q: Although LC/MS has been available for some years, there is a perception that it is too complex/too costly for use in a routine practice compared with more conventional tools. How would you reassure diffident potential users?
A: LC-MS/MS technology was initially used in research-type labs, but it was the pharmaceutical industry that first discovered mass spectrometry’s potential as an alternative technology for bioanalytical assays. About 15 to 20 years ago, the pharmaceutical industry was using UV detection, immunoassays and other types of technologies for their bioanalytical work, but they just weren’t getting the sensitivity and selectivity they needed. LC-MS/MS, using a triple quadrupole mass spectrometer, delivered the sensitivity and selectivity they wanted, so they developed it into a highly robust assay format that could be run under the rigor of GLP in clinical drug development, and drug metabolism and pharmokinetics.
Now a similar adoption is happening in clinical research and toxicology research. They’re discovering that often the current technologies in labs aren’t selective enough, the data quality are not high enough, or the technologies are too expensive or labour intensive. They’re turning to LC-MS/MS because it’s automatable, sensitive, selective, and yes, cost-effective.
People are also turning to us because the solution that Thermo Fisher Scientific has built around LC-MS/MS is making it very cost-effective. We have brought a new meaning to “total solution,” with differentiated sample prep, LC front ends and mass spec technology that are integrated together with easy-to-use software.
We offer a great package that simply has everything clinical labs need, starting with the Thermo Scientific Accela high-pressure pump, which dramatically increases chromatography resolution and selectivity. From there one can upgrade to the Thermo Scientific Transcend system powered by TurboFlow technology, virtually eliminating sample preparation. The Transcend system also allows users to multiplex, running two or four independent LC channels at once through a single mass spectrometer, which is a huge savings in cost and time to run the assays. On the back end, we have new mass spectrometry technologies, such as the Thermo Scientific TSQ Vantage and the Thermo Scientific Exactive, which offer performance that can’t be matched anywhere else. And finally, everything is integrated via software, which really makes what was perceived as a fairly complicated system very easy to run reliably in the clinical research and toxicology research lab settings.
This technology has really matured to a point where it can run reliably in more of a production-type environment, where the real goal is not just to do basic research, but to generate high-quality data in a very easy fashion. The shift in people’s perceptions about LC-MS/MS has really been driven by many of the larger laboratories that have adopted the technology. There it can be seen that mass spectrometry is taking a huge hold because we have brought the data quality and confidence of results up, but at the same time driven costs down with innovative new technology.
Q: Briefly, what major advantage(s) does the use of LC/MS confer?
A: There are a lot of advantages that I think really play across multiple fields.
One big advantage of mass spec is flexibility – it’s a kind of universal detection technology. In the morning a user can do research with steroids, like testosterone, and endocrinology-type assays, and in the afternoon s/he can run an entirely different class of compounds.
Another advantage is sensitivity. The reproducibility of a mass spectrometer is phenomenal, and that leads to better-quality data. Good reproducibility and good data quality enable researchers to go down to very low levels, with high accuracy and precision. Good data also means that costs will be kept down, so people are adopting mass spectrometry technology for clinical research applications because it’s often more cost-effective.
Throughput is also a big advantage. New multiplexing technology gives labs the ability to run multiple channels into a single detector, so labs are justifying the investment based on the ability to carry out high volume. And, because of the flexibility of the platform, they can do high volumes of multiple assays.
I think another advantage for labs is that methods can be developed much faster because there is no need to worry about creating an antibody for an immunoassay, which can be very expensive and take a really long time.
Q: Are there other fields where you think the routine use of LC/MS is, or could be, advantageous?
A: I think there are lots of areas where this technology could make a big difference. One area where we have quite a bit of experience and that holds a lot of promise is proteomics. We’re working closely with a variety of collaborators to move proteomics-based biomarkers to clinical assays, helping researchers to bridge the gap between research and routine in this area.
Q: How has your company enabled the routine use of LC/MS?
A: Thermo Fisher Scientific’s biggest accomplishment for clinical researchers and toxicologists has been putting together a truly complete solution that enables people to not just get better data, but to save money at the same time.
We’ve done a huge amount of work on the front end of LC-MS/MS. Our Accela HPLC system dramatically improves selectivity, while our TurboFlow technology virtually eliminates sample prep and gives people better data. In the same way, our multiplexing capability enables people to run two or four different methods on the same mass spectrometer, essentially giving them four for one on their mass spectrometry investment. Because of this technology, people are able to do projects that simply would not have otherwise been economically practical.
If one puts all that together with some of the incredible mass spectrometry instruments we’ve recently launched, like the TSQ Vantage and the Exactive, one has a profoundly enabling solution. Maybe most importantly, the entire solution is made by Thermo Fisher Scientific, including the software that runs it. There’s no cobbling things together for a solution that has to be supported by multiple vendors; we stand behind everything.
Q: What plans do you have for future developments in this field?
A: Our reputation is really built on our innovation, and we are constantly improving our mass spectrometers and launching new products. For instance, the TSQ Vantage delivers up to 10 times more sensitivity than any other triple quad on the market. The Exactive, which is built on our Orbitrap technology, is another example of innovation. This technology was very enabling in our research-grade instruments, and we’ve just now made it into a benchtop unit to look at using the power of high resolution and accurate mass for the clinical research and toxicology research application space. We’re looking to work that differentiated technology into a number of workflows.
Jeff Zonderman,
Director,
Clinical and Toxicology LC/MS,
Thermo Fisher Scientific.
Franklin, MA, USA
