Mass spectrometry coupling techniques (MS-IR, MS-TG, MS-GC)

Mass spectrometry excels at the ‘qualitative and quantitative’ analysis of individual or mixed components, but lacks the ability to separate samples undergoing physical or thermal processes, or in highly complex systems; it is therefore often ‘coupled’ with other instruments. Coupling (hyphenation) refers to the sequential connection of two analytical methods, whereby the first method provides separation or process information, whilst mass spectrometry provides molecular identification.

Neo Source INSTRUMENT products support a variety of coupling modes. When coupled with thermogravimetry (TG), the mass spectrometer can monitor the gases released whilst the sample loses mass upon heating, allowing ‘mass loss steps’ to be correlated with specific products—for example, in the pyrolysis of coal or biomass, each segment of mass loss corresponds to the release of specific hydrocarbons or oxygen-containing compounds. When coupled with infrared (IR) spectroscopy (as demonstrated in the example ‘MS-IR Coupling Study of the MTH Reaction’ on our website), spectral patterns of both gas-phase desorbed products and adsorbed products can be obtained simultaneously, allowing for mutual verification of changes at both the surface and gas-phase levels. When coupled with gas chromatography (GC), the GC first separates complex mixtures by retention time, followed by peak-by-peak identification via mass spectrometry, making this approach suitable for highly complex systems. The ProC series offers gas chromatography, infrared, and thermogravimetric interfaces, as well as operating software, as optional extras.

The value of coupling lies in ‘complementarity’: chromatography, thermogravimetry and infrared spectroscopy provide information on ‘when and what kind of process’ is occurring, whilst mass spectrometry identifies ‘which molecules’ are present. For New Ceyuan’s online mass spectrometer, this coupling expands its role from that of a standalone ‘real-time gas analyser’ to a component that can be integrated into multi-modal research platforms (such as those investigating catalytic mechanisms, pyrolysis processes and material release). It should be noted that coupling does not alter the mass spectrometer’s inherent non-polar discrimination and wide dynamic range characteristics; it merely broadens the range of analysable scenarios—the mass spectrometer remains responsible for reading the gas composition at every instant, whilst other instruments are responsible for simultaneously recording process variables such as ‘temperature, weight loss and retention time’.

From the user’s perspective, coupling capability means that a single instrument need not ‘go it alone’: When studying pyrolysis, weight loss and gas composition can be analysed simultaneously; when studying catalysis, surface adsorption and gaseous products can be examined concurrently; and when studying material release, release curves can be correlated with specific molecules. This is precisely why New Ceyuan lists ‘non-standard customisation’ (such as thermogravimetric, infrared and GC interfaces, as well as operating software) as key accessories—it sells not merely a mass spectrometer, but a modular analytical system.