The Thermo Scientific Q Exactive hybrid quadrupole-Orbitrap mass spectrometer introduce the concept of Quanfirmation, which means to routinely and confidently identify, quantify, and confirm in a single analysis using a single mass spectrometer. The Thermo Scientific Q Exactive Plus takes Quanfirmation to a new level.
Figure 1. The Thermo Scientific Q Exactive Plus Hybrid Quadrupole Orbitrap Mass Spectrometer
The Structure of the Q Exactive Plus Mass Spectrometer
Figure 2. Schematic of the Q Exactive Plus mass spectrometer
Like Q Exactive mass spectrometer, the Q Exactive Plus consists of six main components, including the ion source, an injection flatapole with mass resolving capabilities, quadrupole mass filter for precursor ion selection, curved linear trap (C-trap) for short selection, collision cell, and Orbitrap analyzer for Fourier transform mass analysis.
The injection flatapole acts as an ion focusing device and also an ion pre-filtering device. To focus the ions along the axis of the lens, an RF voltage is applied to the electrodes. In addition, a DC voltage is applied to the injection flatapole. In positive ion mode, this voltage creates a negative potential difference with respect to the S-lens exit lens. While in negative ion mode, this voltage difference is inverted. In ion pre-filtering mode, additional DC voltages (of opposite sign but equal magnitude) are applied to opposite sets of electrodes to coarsely filter ions falling outside of a wide window around the much narrower window of ions passed by the quadrupole. For quadrupole mass filter, the Q Exactive Plus MS uses advanced quadrupole technology (AQT), which comprises a hyperbolic segmented quadrupole for higher transmission efficiency and optimized transmission window shape.
In Q Exactive Plus mass spectrometer, after samples are introduced into the API source, the injection flatapole transmits ions into the quadrupole. In addition, the injection flatapole also work as coarse pre-filtering of ions according to their mass-to-charge (m/z) ratios. The quadrupole rod can transmit and filter the ions according to m/z ratios. And then ions are transferred into the C-trap, where the ions are accumulated and their energy is dampened with a bath gas. The ions are then injected into the Orbitrap analyzer to obtain mass spectra. Besides, to conduct MS/MS experiment or all-ion fragmentation (AIF), the ions are passed through the C-Trap into the HCD cell for fragmentation. After fragmentation, the ions are transferred back into the C-Trap and injected into the Orbitrap analyzer for detection.
Features of Q Exactive Plus Mass Spectrometer
Figure 3. Features of Q Exactive Plus Mass Spectrometer
- Several approaches to quantitation including selected ion monitoring (SIM), parallel reaction monitoring (PRM), and data-independent acquisition (DIA). In SIM, ions of one or more specific m/z values are are detected, which provides high specificity and sensitivity. In PRM, a predefined precursor ion is selected in the quadrupole and transferred through the C-trap to the HCD cell for fragmentation. After fragmentation, fragment ions are transferred back to the C-trap and eventually injected and analyzed in the Orbitrap mass analyzer. In DIA, all ions within a selected m/z range are fragmented and analyzed in a second stage of MS/MS, where the data can be researched later with an improved library to generate even better data.
- Advanced axial beam guide (AABG) for greater sensitivity and maximum robustness. AABG with prefiltering second-generation axial field bent flatapole ion guide reduces noise by preventing neutrals and high-velocity clusters from entering the quadrupole.
- Advanced quadrupole technology (AQT) for superior precursor isolation. AQT with a segmented quadrupole mass filter can provide increased ion transmission and superior isolation window shape. And the variable precursor isolation width selection ranges from 0.4D to full mass range. AQT optimizes precursor selection and transmission, improving quantitation of low-abundance ions in the most complex matrices.
- Optional intact protein mode. It provides superior trapping of large molecules for improved analysis of intact proteins and protein complexes.
Applications of Q Exactive Plus Mass Spectrometer
The Q Exactive Plus mass spectrometer accelerates a wide range of applications.
- Protein identification. The Q Exactive Plus MS can increase sensitivity and precision for protein identification. The AABG and AQT improve identification of low-abundance proteins in complex matrices while providing the utmost reliability and confidence.
- Intact proteins characterization. With the new intact protein and enhanced resolution modes, the Q Exactive Plus system can confidently analyze intact proteins and isotopically resolve subunits as large as 50 kDa with outstanding sensitivity. This may be a good choice for the therapeutic proteins and monoclonal antibodies (mAb) analysis.
- Quantification with high confidence. The Q Exactive Plus mass spectrometer with AQT to optimize the ion selection and transmission, improving the quantification of low abundance ions within narrow isolation windows, which can be used for isobaric mass tagging (like Tandem Mass Tag, TMT). The Q Exactive Plus system with PRM and high-resolution accurate-mass selected ion monitoring (HR/AM-SIM) can quantify peptides and small molecules with superior sensitivity and unmatched selectivity. In addition, DIA can provide a high-throughput for protein quantification and qualitative confirmation.
The Q Exactive Plus mass spectrometer combines the quadrupole precursor selection with HR/AM Orbitrap to provide identification and quantitation of more compounds with greater confidence. At Creative Proteomics, we can provide the reliable services to meet a variety of requirements by using the Thermo Scientific Q Exactive Plus hybrid quadrupole Orbitrap mass spectrometer.