The HP 5971A Mass selective detector is a stand-alone capillary GC detector designed for use with the HP 5890 A Gas chromatograph .
The base model includes:
- Cast – aluminum vacuum manifold
- Vapor diffusion high vacuum pump
- Mechanical foreline ( roughing ) pump
- Electron impact ion source
- Hyperbolic quadrupole mass filter
- Electron multiplier ( detector )
- Instrument control electronics
- Power supplies
- GC/MSD interface
Real-time control of the MSD is provided by the MSD electronics according to setpoints and instructions from the data system. The data system sends operating parameters to the MSD and receives status information and data from the MSD.
The data system software includes programs to calibrate the MSD, acquire data, and process data. It also includes utilities for file management and editing. Tuning programs can adjust voltages in the ion source, calibrate mass assignments, and control the scanning of the mass analyzer. Data acquisition programs allow you to monitor the total ion current, automatically storing the mass spectra of GC peaks as they elute ( scanning mode ) or, alternatively, to monitor the concentrations of particular ions ( selected ion monitoring mode ).
Dynamic range: A logarithmic preamplifier provides more than six decades of dynamic range.
Ionization energy: 70 eV from either filament.
Mass axis stability: +/- 0.15 amu per 12 hours assuming recent calibration, adequate ion statistics, and thermal equilibrium of the electronics.
Mass range: 1.2 – 650 amu.
Mass resolution: 0.5 +/- 0.05 amu throughout the mass range.
Scan speed: Eight user-selected scan rates with a maximum of 2000 amu/sec with 0.1 amu mass resolution.
SIM mode: In the selected ion monitoring mode (SIM) the MSD monitors up to 20 individually selected masses at a time. Up to 200 groups of 20 masses can be selected for each run. Dwell time for each mass is user-selectable from 10 msec to 32767 msec.
Temperature control: The GC/MSD interface temperature is user-settable from 250° to 320° C. The end of the GC/MSD interface conductively heats the ion source and mass filter. The vacuum manifold is not otherwise heated.
Total ion mode: AC voltage-only mode, with adjustable low-mass cut-off, allows the HP 5971A to operate as a non-specific, high-sensitivity detector.
Vacuum system: Vacuum is maintained by a vapor diffusion pump backed by a two-stage, direct-drive mechanical pump. Overall system pumping speed is approximately 60 liters/sec for helium. The vacuum system can accommodate capillary flow rates up to 1ml/minute of helium.
Size: Height – 34 cm 13.4 inches Width – 17 cm 6.7 inches Depth – 65 cm 25.6 inches Weight – 21 Kg 46 lbs excluding the external mechanical pump.