The Gold Standard for Quantitative Measurement

By March 3, 2017

Tandem quadrupole mass specs: Made to measure

vials-350Not that long ago  they were as big as a car and cost so much that only the most well-funded research institutions were able to afford them, along with the scientists that knew how to run them.

Fast forward 50 years. Today’s tandem quadrupole mass spectrometers – some use the term “triple quadrupole” or QqQ – bear little resemblance to those of the 1960’s and 1970’s in size, capability and usability.

Tandem quadrupole mass spectrometers are in a class of their own. They have become today’s go-to, general-purpose measurement tools.

“Tandem quads” or “tandems” are prized for their selectivity and sensitivity. In the pharmaceutical industry, tandem quads coupled to a UPLC system provide quantitative measurements of active drugs and their metabolites to generate accurate PK/PD, toxicokinetic and bioequivalence data which, of course, are fundamental to the drug development process.

“Triple quadrupole mass spectrometry has become the gold standard for performing quantitative bioanalysis in discovery as well as regulated bioanalytical groups.

“When the triple quad is coupled to a UPLC it’s looking for a very specific retention time as well as a fragmentation pattern for the analyte or analytes of interest. It is this marker of the analytes that is responsible for the excellent selectivity and sensitivity.”

Dr. Christopher Evans, Director Bioanalytical Sciences and Toxicokinetics, GSK

What makes up a tandem or triple quadrupole MS?

The feature of a tandem quadrupole mass spec that sets them apart is the twin quadrupole mass analyzers on either side of a collision quadrupole.

  • As the name implies, a quadrupole consists of four precisely parallel rods (called poles) equally spaced around a central axis.
  • As the precursor ions introduced by the ion source travel along the axis of the first quadrupole, the quadrupole separates them according to their mass-to-charge (m/z) ratio.
  • They then enter the collision quadrupole which fragments them into smaller, product ions. The second quadrupole mass analyzer then separates the product ions according to their unique m/z ratio whence they are beamed toward the mass detector.
Schematic for a Waters tandem quadrupole MS

Schematic for a Waters tandem quadrupole MS

With an estimated 14,000 tandem quads of every stripe in use worldwide – and the number of installations growing by a net 1,500 units per year – they are a mainstay of pharmaceutical research and development, analytical services, forensic toxicology, biomarker verification, food and environmental testing and clinical laboratories.

Advancing tandem quad MS technology for three decades

Waters’ long tradition of innovation in tandem quadrupole mass spectrometry dates back more than 30 years. With each new tandem quad instrument, Waters packs more innovation and analytical power into a smaller and smaller frame. Waters newest tandem quad, the Xevo TQ-XS, is no different. This instrument features StepWave XS ion guide for focusing ions and eliminating neutral ions and gases, making it the most sensitive tandem quad mass spectrometer on the market today.

Equipped with Waters tandem quads, our customers are making new discoveries every day, publishing their work in more than 500 papers every year. And the number of papers only continues to grow as applications for the technology continue to blossom.

If you are attending Pittcon 2017 in Chicago, plan on checking out our booth #2420 where you can see the new Waters Xevo TQ-XS on display.

  • Oral presentation: Towards an Automated Untargeted Method for Microcystins Analysis Using Two Dimensional Liquid Chromatography and Ion Mobility/Quadrupole Time of Flight Mass Spectrometry, with Ken Rosnack. Tuesday 9:30 (session 980-4)
  • Workshop: Discrimination of Honey of Different Botanical Origins Using an Untargeted High-Definition Metabolomic Workflow, with Ken Rosnack. Wednesday 3:50 (session 1885-5)
  • Posters: Fast and Reliable Analysis of Isoflavones in Dietary Supplements Tuesday (1420-7 P); Accessible and Efficient Screening of Multiclass Contaminants in Food Wednesday (2050-1 P)

Infographic: Evolution of Tandem Quadrupole Mass Spectrometry Technology

Infographic: Evolution of Tandem Quadrupole Mass Spectrometry Technology



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