 |
|
|||||||||
 |
 |
|
|
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
|
|||||||||
|
|
|||||||||
Updated: 12.01.2010 
|
|
The Mass Spectrometer
Our laboratory is equipped with three isotope ratio mass spectrometers (Finnigan MAT, delta S, delta XL plus, delta XP) for the measurement of 13C/12C, 15N/14N, 18O/16O and D/H in gases, organic matter and water. The delta S has a dual-inlet system and 8 Faraday cups. Two elemental analysers are coupled online to the delta S via a Conflo II interface for the combustion/pyrolysis of organic material.
For the analyis of water, we have an equilibration device for 18O and a H/Device for D/H determination and a high-temperature pyrolysis unit which is connected with the delta XP MS. Below are given details of the mass-spectrometer "Delta plus" as copied from the homepage of Thermo-Finnigan
DELTA plus The Analyzer The new ion optics of the DELTA plus provide optimal stigmatic (double direction) focusing for all gas species including H2, which leads to close to 100 % transmission of all ion beams. The excellent peak shape and high abundance sensitivity contribute to the outstanding reproducibility of the measured isotope ratios. The new self-aligning ion source combines high sensitivity with excellent linearity, and comes with specifications for both of these important parameters. Its inherent stability guarantees optimum performance for all gases with one set of tuning parameters - a prerequisite for reliable long-term operation. The ion source is mounted on the front flange for easy maintenance and is contained in a monolithic housing machined from a single block of stainless steel. The weld-free design with integrated heating, first introduced for the MAT 252, virtually eliminates memory and background. The ion source is pumped by a high capacity (240 l/s) two-stage turbo-molecular pump with a high compression ratio for both He and H2.
The DELTA plus brings you: The Detection System The standard DELTA plus comes with a truly universal triple Faraday cup collector system suitable for N2, O2, CO2, and SO2. This collector consists of one small and two wide, individually shielded deep Faraday cups, each with dedicated secondary electron suppression and a dedicated highly stable preamplifier. The digitization system is based on Finnigan's patented V/F converter with inverse frequency measurement, which is needed to guarantee accurate measurement of small signals. Measurement of H/D from the stigmatically focused H2 and HD ion beams is supported by the optional H/D collector system with two Faraday cups and preamplifiers. Both sets of detectors can be accessed during one experiment (e.g. for background checks). Optionally, two alternative 6-cup collector systems are available for special requirements, e.g. different feedback resistors for different isotope ratios. The Package Premium analytical performance is packaged in a small footprint cabinet, which is designed to serve also as a bench on which to place peripherals. Easy access to all parts requiring periodic maintenance is built in, and the system can be moved on its own wheels. Special care has been taken to significantly reduce the noise level of the instrument. Automation The instrument is fully automated by built-in microprocessor control, linked to a powerful data system. Data processing is based on a real time multitasking operating system, implemented on current PC hardware. The application software package ISODAT TMis graphics oriented, comprehensive and flexible.Simultaneous data acquisition, data evaluation and sample preparation guarantee high productivity. Configure YOUR DELTA plus The DELTA plus can be tailored to meet YOUR analytical requirement. DELTA plus Configurator (image 120K) Continuous Flow The DELTA plus is designed to provide uncompromising performance for continuous flow applications. The 240 l/s pumping speed of the two-stage turbomolecular pump is fully available at the ion source because the pump connects directly to the ion source housing, without any intermediate tubing. The two-stage pump incorporates a molecular drag stage and delivers high compression for He (3 x 10^5) and H2. In addition, the DELTA plus can be equipped with a true differential pumping system to handle high He carrier gas flow rates while maintaining a factor of 10 pressure drop between the ion source housing and the analyzer, which leads to excellent abundance sensitivity and linearity. A wide variety of inlet and preparation systems is available, including GC combustion (GC/C II), elemental analyzer (ConFlo II), trace gas pre-concentrator (PreCon) and others. Exciting new on-line inlet systems are in preparation. Dual Inlet A dual inlet system can be fully integrated with no increase in footprint. The newly designed layout has improved integrated heating for all valves and capillaries, and integrated pressure readout on both the sample and the standard side. The valves are our unique, field-proven gold-sealed, gold-seated all-metal design, thus ensuring that the sample gas has no contact with any plastics or polymers. The valves are proven to have extremely low dead volumes and negligible memory, and require almost no maintenance. An automated microvolume inlet system capable of temperature control over the whole operating range is optionally available. Dual Inlet A newly designed fully integrated multi-port inlet has been developed for automation of the dual inlet system. It is of mono-block design, with integrated heating. It also uses the unique all-metal gold-sealed, gold-seated valves, allowing us to provide guaranteed specifications for external reproducibility. All valves, including the changeover valve, are identical with interchangeable parts, leading to further reduced cost of maintenance. Various preparation systems (e.g. HDO equilibration, Kiel II carbonate device) using the dual inlet system are available to expand the routine use of high precision isotope ratio measurements. Copyright (c) 1997, Finnigan Corporation, San Jose, CA 95134,USA.
|
|
|
