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Design
Integrated bench-top unit of a mass analyser and Dumas combustion unit
with vertical mounted furnaces. Built in pressure and flow sensors, isothermal
GC and software controlled variable oxygen input.
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Analytical
Mode Samples in capsules are converted to N2, and CO2
by combustion and measured by the integrated isotope ratio mass spectrometer.
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Ion
source High sensitivity, electron impact, plug-in design.
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Magnet
Permanent.
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Resolution
= 95 (N2) 10% valley definition.
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Sensitivity < 1500 molecules per mass 44 ion.
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Abundance
Sensitivity < 300 ppm for CO2 at 4 x 10-6 mbar in continuous
flow mode. (Software function allows calibration to zero to ensure accuracy.)
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Linearity
Changing from 100 to 1500 µg C will effect a change of <0.2‰.
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Vacuum
Turbomolecular pump (70 L/s) backed by a two-stage rotary pump. Ultimate
vacuum of 1 x 10-8 mbar. Source pressure monitored by active gauge.
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Inlet
Built-in capillary inlet with fail-safe pneumatic valve.
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Water
Removal Re-chargeable magnesium perchlorate trap.
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CO2
Removal Re-chargeable Carbosorb trap. Software selectable.
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Gas
Control High quality stainless steel diaphragm regulators. Gas flow rates
controlled by crimps. Software controlled oxygen pulse for efficient and
economical combustions. A software controlled flow diverter valve selects
the GC effluent to go to the mass spectrometer or to waste. Normally closed
solenoid valves to prevent gas wastage during laboratory power cuts.
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Sample
Range Solids/Liquids:- 5 to 1000 µg N, 5 to 2000 µg C. (NB.
samples down to 0.5 µg can be measured with reduced precision).
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Analytical
Cycle 4 min per sample (15N only)
7 min per sample (15N and 13C)
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Autosampler
66 position pneumatic autosampler that takes (standard) capsules with
dimensions up to 12 x 6mm. Software controlled. Extra carousel (to allow
up to 130 samples) or large hole version available as options.
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Data
acquisition Data acquisition system uses state of the art highly stable
and linear high frequency converters which produce integral slices with
zero dead time and quantisation below the beam statistical noise floor
at all signal levels.
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Software
Proprietary operational software for system control and data handling.
Fully compatible with Windows 3.1, ‘95’ and NT.
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Electronics
Flashover resistant source electronics. Full control and monitoring of
all instrument parameters through software and on-board micro-processors.
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Dimensions
770mm wide, 520mm deep, 555mm high.