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The TSQ QuantumTM series of mass spectrometers are the most advanced and powerful set of triple quadrupole mass spectrometers available in the world today, featuring the patented HyperQuad Quadrupole mass analyzer system, a rugged orthogonal source, and a completely redesigned analyzer geometry for maximum sensitivity, precision, and reliability. One of the key features of the TSQ Quantum which sets it apart from any other commercially available triple quadrupole instrument is the ability to carry out H-SRM for quantitative assays.
What is H-SRM ?
H-SRM is an acronym for Highly-Selective Reaction Monitoring, which is a more advanced form of Selective Reaction Monitoring (SRM). SRM is a longstanding quantitative technique used on triple quadrupole mass spectrometers for quantitation. During the SRM experiment there are three distinct events which occur within the triple quadrupole mass spectrometer.
First, ions of a specific mass (precursor ion) are transmitted through the first quadrupole, while ions of different masses are filtered out. Second, the selected ions collide with a neutral gas present in the second quadrupole (collision cell) where they undergo collisional induced decomposition (CID). Third, product ions of specific mass are then transmitted through the third quadrupole, after which they are detected. In this way a specific signature can be set up for target analytes in a complex sample.
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The SRM experiment using most triple quadrupole instruments is usually conducted at unit (or higher) resolution for the precursor ion. However, with H-SRM, the precursor ion is selected at a higher resolution, typically at 0.1 FWHM without significant loss of transmission of your analyte (Fig 1). This is achievable due to the patented HyperQuad Quadrupole technology used on the Quantums. No other commercially available triple quadrupole system can currently achieve this.
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| The Advantages of H-SRM over SRM
H-SRM can eliminate chemical noise, lower detection limits, and reduce the likelihood of generating false positives. Two examples are shown here to illustrate this. Figure 2 shows a proprietary pharmaceutical compound in brain matrix being analyzed by SRM and H-SRM. Figure 3 shows Clenbuterol being analyzed in human urine in SRM and H-SRM modes. As is clear from these two example, the more stringent tolerances at (0.1 FWHM) accounts for the higher selectivity of the analyte, which leads to lower LOQs and increased precision and accuracy values especially at the limits of detection, thus giving you more confidence in your quantitative assays.
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Figure 3 Quantitative analysis of Clenbuterol in human urine using SRM and H-SRM.
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