Integrating an autosampler is the simplest and most cost-effective way to leverage high sample throughput from the rapid analysis provided by Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). Furthermore, an autosampler improves repeatability and reproducibility compared to manual analysis and it eliminates operator error.
Recently we evaluated headspace autosamplers from the major manufacturers for suitability of integration with SIFT-MS. We came to the conclusion that GERSTEL GmbH & Co. autosamplers provide a great off-the-shelf option for integration with our SIFT-MS instruments. We are delighted to work with GERSTEL to provide turnkey automated SIFT-MS solutions for routine and R&D laboratories.
Here’s how we came to our decision:
As a direct mass spectrometry technique (that is, one that has no pre-separation using chromatography), SIFT-MS has very different requirements for an autosampler compared to gas chromatography. In a nutshell:
- GC-based techniques require rapid injection to achieve good chromatographic separation. Separation necessarily leads to prolonged analysis as individual compounds elute from the column over a period of time.
- SIFT-MS requires steady sample injection for the duration of the analysis, because analysis is carried out simultaneously with injection. In SIFT-MS, separation is achieved through mass spectrometry coupled with ingenious application of ultra-soft chemical ionization: eight reagent ions are available and automatically switched by software control of a quadrupole mass spectrometer.
The differences between GC and SIFT-MS are illustrated in the following graph. Injection onto the GC column is very rapid, but sample analysis is very slow. In contrast, the analysis is completed rapidly in SIFT-MS because the sample is analyzed as it is injected.
The slow injection requirement really narrows the commercially available options for SIFT-MS. Three operating principles are used in modern headspace autosamplers: loop injection, pressure-balanced introduction, and syringe injection. Of these, the syringe injection principle is best suited to integration with SIFT-MS.
We chose GERSTEL products, because their MPS autosamplers are based on syringe injection, already accommodate the slow sample injection required by SIFT-MS, have class-leading Gerstel Maestro software, and are very flexible to meet the new application requirements and changing needs of our customers.
By coupling GERSTEL automation with the high throughput of SIFT-MS, laboratory productivity that was previously unimaginable has become a reality.