Postcolumn hyphenation

Combined chromatographic-spectroscopic techniques allow complex multicomponent data to be obtained in a single experiment. Essentially, the analysis of monomers, additives, oligomers and polymer can be performed in one step on-line. Postcolumn hyphenation, which comprises spectroscopic detectors, sniffing, fraction collection or heartcutting, is well 

When interfacing any detection method to a separation process, the integrity of the separation must be maintained. The resolution between two components, which is gained during a highly efficient separation, can 

Hyphenation of chromatographic separation techniques (SFC, HPLC, SEC) with NMR spectroscopy as a universal detector is one of the most powerful and time-saving new methods for separation and structural elucidation of unknown compounds and molecular compositions of mixtures [171]. Most of the routinely used NMR flow-cells have detection volumes between 40 

Problems arise in interfacing column chromatographic techniques to a mass spectrometer from the difference in material flow requirements between the two instruments and the desire to generate information about the sample without interference from the mobile phase in which it is diluted. The most favourable case occurs for gas 

The ideal mass-spectrometric interface should allow for a range of ionisation methods (Tables 7.23 and 7.24). The ionisation of organic molecules for use with chromatographic outlets include El, Cl, APCI for samples that can be vaporised prior to ionisation alternative ionisation techniques using TSP, ESP or FAB are needed for labile, high-MW or ionic samples. 

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The solvents used in extraction may affect subsequent chromatography. Precolumn hyphenation is considered to be much more difficult and critical than the more developed postcolumn hyphenation. Sample preparation and injection are considerable bottlenecks in terms of ruggedness. 

Table 7.22 Main postcolumn hyphenated techniques used in polymer/additive analysis...

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