In order to purchase the most appropriate analytical system, some details of the desired analysis must be considered. A versatile approach to general organic analysis is a system based on Gas Chromatography (GC). Chromatographs can be used with non-selective, general purpose detectors or selective detectors, though most GC detectors cannot be operated either way (the exception is the mass spectrometer detector, which can be used as a general and highly selective detector in a single experiment). Though the GC based analysis can provide limited qualitative data, GC is better suited to quantitative analysis.