Detectors in SFC with Reference to Carotenoid Analysis

SFC is compatible with a wide range of detection methods. The two basic types of detectors are the ionization detectors and optical detectors. Most commercial open tubular SFC systems provide a flame ionization detector (FID) as standard and it is therefore the most widely used detector for carotenoids. However, detection of carotenoids in supercritical fluids following chromatographic separation has also been achieved using mass spectrometry (MS) and UV/Vis detectors. SFC-MS provides detailed information on the molecular structure of eluted carotenoids and greatly aids peak identifications. Due to the thermal instability of these compounds, 'soft' chemical ioniz-ation is recommended. Use of methane as the chemical ionization reagent gas and a low source temperature of 100-120°C results in minimal fragmentation, even for thermally labile carotenoids. For more routine analysis, online UV-Vis monitoring (especially using photodiode array detection) is now the standard procedure for the analysis of carotenoids by HPLC and is the preferred detection system for the SFC analysis of carotenoids, with a number of high pressure, temperature-regulated flow cells being available. The effects of pressure and temperature on the absorption spectra of carotenoids dissolved in supercritical carbon dioxide are discussed in the following section.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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