Development of an expert system for gas chromatography : mass spectrometry, hydrocarbon data interpretation and an equilibrium model for the effect of neutral surfactants in reversed-phase high performance liquid chromatography

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An expert system computer program has been developed to automatically arrive at decisions normally made by a highly specialized highly skilled analytical chemist in the routine interpretation of data from a Gas Chromatography/Mass Spectrometry (GC/MS) data system. The specific purpose of the expert system is to set chemical limits within which the system accepts one or more of nine candidate compounds ("spectral matches") provided by a commercially available data system. This is accomplished by assuming that each gas chromatographic peak might be a mixture; deconvoluting each peak using mass spectral "type analysis" into as many as 3 possible components of each of as many as 8 different types; and assigning a carbon number range to each possible component based on its elution time. A library identification is assigned if and only if (a) it is within these type and carbon number limits, and (b) the corresponding deconvoluted spectrum also show a good "match" or "fit" with the library spectrum. If the library identifications are unacceptable, the component is assigned a generic identification in terms of component type and carbon number. The expert system was constructed to retain the human expert's knowledge and to reduce the need for the expert whose specialized skills can be used more productively in non-routine areas. The effect of solute ionization and the concentrations of nonionic and zwitterionic (neutral but charged) surfactants on the retention times of weak acids, bases, and ampholytes in reversed-phase high performance liquid chromatography was investigated. An equilibrium model based upon interaction among eluent and solutes is derived to predict the retention behavior. [...]

Gas chromatography--Data processing, Mass spectrometry--Data processing