Mass spectrometer IsoPrime

For many years, the Department of Radioisotopes has been involved in environmental research. Its main aim is the reconstruction of timescales for the environment evolution in the last 300 thousand years. The reconstruction is performed on the basis of radiocarbon and luminescence dating, as well as lead dating of young sediments; the dating is supplemented by investigating characteristic features of the environment based on investigation of carbon and oxygen stable isotopes. In the last six years, isotopic measurements have been performed in tree rings (since 2 years - within the project ISONET).

A public bid for the purchase of the spectrometer was successfully completed in mid-December, 2004. The bid was won by the company "Comef" who signed the contract with the Silesian University of Technology; the complete spectrometer system was delivered and installed at the end of July/beginning of August 2005.

Parameters of the instrument

The IsoPrime mass spectrometer is used for the determination of light stable isotope ratios (hydrogen, carbon, oxygen and sulphur); the instrument is of the continuous flow type. The elemental analyser EuroVector is used for the preparation of organic samples in the measurement system.

The mass spectrometer in conjunction with an elemental analyser is a modern instrument which enables the measurement of the isotope ration of light stable isotopes in gases and in organic and inorganic samples. The samples introduced to the ion source of the spectrometer have to have the form of gaseous N₂, O₂, CO₂, SO₂, CO or N₂O. In addition, an electromagnet for analysing the ratio H/D is installed. The gas is injected into the spectrometer by a special injection device working in continuous flow mode.

The main parts of the spectrometer are:

• investigated sample and standard gas injection system,
• ion source,
• ion beam analysis system equipped with an electromagnet separating gas ions for the analysis of the D/H ratio, carbon, nitrogen, oxygen and sulphur,
• collectors of measurements of carbon, nitrogen, oxygen and sulphur,
• vacuum line with vacuum pumps,
• computer system for measurement management with analysis software,
• the spectrometer can be upgraded for working in the dual inlet mode as well.

The main parts of the elemental analyser are:

• combustion ovens with temperature stabilisation systems,
• reactors for combustion, reduction and pyrolysis of organic samples (depending on the needs the analyser can be configured for measuring: C, O, N, H or S),
• gas chromatograph system for separating gasses created during the reaction and injecting them into the spectrometer,
• automated system for sample preparation in gas form,
• automated sample feeder for 78 samples.

Mass spectrometer system from the left: computer system for controlling the operation of the spectrometer, as well as registering and analysing measurement results, elemental analyser serving as the sample preparation system, mass spectrometer, system for injecting samples and standard gasses into the ion source of the spectrometer.

The system for injecting standard gasses and investigated into the ion source of the spectrometer.

A screenshot of the measurement control, data acquisition and results analysis software.

An example of a spectrum registered during the measurements of isotopic carbon composition. The first, square peak originates form the reference gas and the second, Gaussian peak from the measured sample.