Gas Chromatography Mass Spectrometry GC-MS unite two powerful techniques to be able to offer the identification of substances that have low detection limits and possible necessary for quantitative analysis. Gas Chromatography Mass Spectrometry analyses works on fluids, solid and gaseous samples but are primarily limited to semi volatile and volatile chemicals. Under Gas Chromatography, a sample is carried and volatilized and carried from the inter gases via a coated glass Capillary Column. The stationary phase is joined into the inside of the column and the amount of time that it takes a particular compound of an element to maneuver through this column to a sensor is known as its Retention Time. These dimensions are used for identification purpose when compared to references.
Under usual Mass Spectrometry or MS step below the Gas Chromatography Mass Spectrometry, the chemicals leaving the GC columns are fragmented by the electron impact. These charged fragments are detected gradually and the following spectrum obtained is used to identify the molecules. Fragmentation patterns are reproducible and consequently, can be used to make quantitative measurements. Gas Chromatography Mass Spectrometry analysis is done on gases, fluids and solids. For gases and fluids, the samples are usually injected right into the Gas Chromatogram. For the solid components, the analysis is carried our throughout grassing or desorption, solvent extraction or pyrolysis. Desorption experiment is done under the stream of helium gas at controlled temperatures ranging from 40 to 300 degree Celsius. The analytes are then collected on a Cryogenic trap during desorption procedure. The sample chamber is a 1.25×4 cylinder.
Pyrolysis is yet another sampling technique employed for the analysis of substances which are impossible to be injected into Gas chromatogram Mass Spectrometry. Under this process, heat is directly applied to the sample which contributes to breaking down of these molecules in a reproducible way. These smaller molecules are subsequently introduced at the Gas Chromatogram and examined from the GC-MS. By this process, probe temperatures of around 1400ºC may be used. Several other sampling Methods and sample preparation can be found such as static headspace analysis, derivatization, purge and trap, Solid Phase Micro extraction etc. using software based on species of interests and sample types.
- Identification of organic elements through separating complex mixtures
- Quantitative analysis
- Trace determination of organic contamination low to mid-ppb amount for liquid matrices and low nanogram level for solid matrices?
- Identifying and measuring volatile organic compounds in mixtures
- Out gassing studies
- Testing for residual solvents
- Assessing contaminants on semiconductor wafers or other tech products thermal desorption
- Identifying trace impurities in fluids or gases