Micromass Quattro LC

Available from KRSS including installation, training and 3 months warranty a used fully refurbished and serviced Micromass Quattro LC.

The Quattro LC is a low resolution, nominal mass accuracy triple quadrupole (QQQ) tandem mass spectrometer.  It is capable of ionization via ESI and atmospheric pressure chemical ionization (APCI).  This instrument is capable of analyzing a wide variety of polar biological molecules via single stage MS.  It also is able to perform MS/MS utilizing product, precursor, or neutral loss scans for structure elucidation or in conjunction with LC and MRM analysis for quantitation.

* Price excludes MS-Workstation available at additional cost. Please call for details

  • Overview
  • Vacuum System
  • Ionisation Techniques
  • Sample Inlet
  • Why purchase used refurbished
    mass specs from KRSS
  • Find Out More

Overview

The Micromass Quattro LC is a high performance benchtop triple quadrupole mass
spectrometer designed for routine LC-MS-MS operation. Quattro LC may be coupled
to:

  • a HPLC system with or without an autosampler.
  • an infusion pump.
  • a syringe pump.

Ionisation takes place in the source at atmospheric pressure. These ions are sampled through a series of orifices into the first quadrupole where they are filtered according to their mass to charge ratio (m/z).

The mass separated ions then pass into the hexapole collision cell where they either undergo collision induced decomposition (CID) or pass unhindered to the second quadrupole. The fragment ions are then mass analysed by the second quadrupole. Finally the transmitted ions are detected by a conversion dynode, phosphor and photomultiplier detection system. The output signal is amplified, digitised and presented to the data system.

MS Operating Modes


MS1
Collision Cell
MS2
MS
Resolving
RF Only (Pass all masses)
MS2
RF Only (Pass all masses)
Resolving

The MS1 mode, in which MS1 is used as the mass filter, is the most common and most sensitive method of performing MS analysis. This is directly analogous to using a single quadrupole mass spectrometer.

The MS2 mode of operation is used, with collision gas present, when switching rapidly between MS and MS-MS operation. It also provides a useful tool for instrument tuning and calibration prior to MS-MS analysis, and for fault diagnosis.

MS-MS Operating Modes


MS1
Collision Cell
MS2
Daughter Ion Spectrum
Static (parent mass selection)
RF only (pass all masses)
Scanning
Parent Ion Spectrum
Scanning
Static (daughter mass selection)
Multiple Reaction Monitoring
Static (parent mass selection)
Static (daughter mass selection)
Constant Neutral Loss Spectrum
Scanning (synchronised with MS2)
Scanning (synchronised with MS1)

The Daughter Ion Spectrum

This is the most commonly used MS-MS scan mode. Typical applications are:

  • Structural elucidation (for example peptide sequencing).
  • Method development for MRM screening studies:
    • Identification of daughter ions for use in MRM “transitions”.
    • Optimisation of CID tuning conditions to maximise the yield of a specific daughter ion to be used in MRM analysis.

The Parent Ion Spectrum

Typical application:

  • Structural elucidation.
    • Complementary or confirmatory information (for daughter scan data).

MRM: Multiple Reaction Monitoring

This mode is the MS-MS equivalent of SIR (Selected Ion Recording). As both MS1 and MS2 are static, this allows greater “dwell time” on the ions of interest and therefore better sensitivity (~100x) compared to scanning MS-MS.

Typical application:

  • Rapid screening of “dirty“ samples for known analytes.
    • Drug metabolite and pharmacokinetic studies
    • Environmental, for example pesticide and herbicide analysis.
    • Forensic or toxicology, for example screening for target drugs in sport.

The Constant Neutral Loss Spectrum

The loss of a specific neutral fragment or functional group from an unspecified parent or parents.

Typical applications:

  • Screening mixtures, for example during neonatal screening, for a specific class
    of compound that is characterised by a common fragmentation pathway.

Vacuum System

Vacuum is achieved using a direct drive rotary pump, and two turbomolecular pumps. The rotary pump, mounted on the floor external to the instrument, backs the turbomolecular pumps and also pumps the first vacuum stage of the source. The turbomolecular pumps evacuate the analyser and ion transfer region. These pumps are both water cooled.

Vacuum measurement is by an active inverted magnetron (Penning) gauge for the analyser and a Pirani gauge for the gas cell. The Penning gauge acts as a vacuum switch, switching the instrument out of the OPERATE mode if the pressure is too high. The speed of each turbomolecular pump is also monitored and the system is fully interlocked to provide adequate protection in the event of a fault in the vacuum system, a failure of the power supply or vacuum leaks.

Ionisation Techniques

Two atmospheric pressure ionisation techniques are available.

Atmospheric Pressure Chemical Ionisation

Atmospheric pressure chemical ionisation (APcI) generally produces protonated or deprotonated molecular ions from the sample via a proton transfer (positive ions) or proton abstraction (negative ions) mechanism. The sample is vaporised in a heated nebuliser before emerging into a plasma consisting of solvent ions and formed within the atmospheric source by a corona discharge. Proton transfer or abstraction then takes place between the solvent ions and the sample. Eluent flows up to 2 ml/min can be accommodated without splitting the flow.

Electrospray

Electrospray (ESI) ionisation takes place as a result of imparting a strong electrical charge to the eluent as it emerges from the nebuliser. An aerosol of charged droplets emerges from the nebuliser. These undergo a reduction in size by solvent evaporation until they have attained a sufficient charge density to allow sample ions to be ejected from the surface of the droplet (“ion evaporation“).

A characteristic of ESI spectra is that ions may be singly or multiply charged. Since the mass spectrometer filters ions according to their mass-to-charge ratio, compounds of high molecular weight can be determined if multiply charged ions are formed. Eluent flows up to 1 ml/min can be accommodated although it is often preferable with electrospray ionisation to split the flow such that 100 to 200 µl/min of eluent enters the mass spectrometer.

Nanoflow Electrospray

The optional nanoflow interface allows electrospray ionisation to be performed in the flow rate range 5 to 1000 nanolitres per minute.

For a given sample concentration, the ion currents observed in nanoflow are comparable to those seen in normal flow rate electrospray. Great sensitivity gains are therefore observed when similar scan parameters are used, due to the great reductions in sample consumption.

Sample Inlet

Sample is introduced from a suitable liquid pumping system along with the nebulising gas to either the APcI probe or the electrospray probe. For nanoflow electrospray, metal coated glass capillaries allow the lowest flow rates to be obtained while fused silica capillaries are used for flow injection analyses or for coupling to nano-HPLC.

 

Why purchase used refurbished
mass specs from KRSS

KRSS Ltd offer high quality pre-owned Mass Spec, LCMS, GCMS, HPLC and GC systems allowing affordable entry into a rapidly developing market.

All KRSS instruments are thoroughly inspected by manufacturer trained engineers (including all components and parts), cleaned and decontaminated, completely refurbished (defective parts and components are replaced with genuine parts), serviced and bench tested to ensure the equipment meets the manufacturers original specifications - this guarantees quality, performance and reliability at a fraction of the OEM costs.

With over 50 instruments in stock, covering all major manufacturers KRSS has systems for a variety of application requirements. All instruments are supplied with a comprehensive warranty and optional service contracts to ensure trouble free operation.

 

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