Application of two-dimensional liquid chromatography to complex mixtures

• Autor(a) principal: Matos, João Tiago Viana de
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/8177
• topic: Química analítica; Cromatografia líquida; Separação química; Vinho

The operation of advanced chromatographic systems, namely comprehensive two-dimensional chromatography coupled to multidimensional detectors, allows achieving a great deal of data that need special care to be processed in order to characterize and quantify as much as possible the analytes under study. This dissertation starts by identifying the main trends, research needs and gaps on the techniques for data processing of multidimensional data sets obtained from comprehensive two-dimensional chromatography. Apart from using other concepts from one-dimensional chromatography, which have not been tested for two-dimensional chromatography, there is still room for new improvements and developments in algorithms and software for dealing with two-dimensional comprehensive chromatographic data. Therefore, this work presents a new two-dimensional chromatographic response function (CRF2D) for the estimation of the quality index of separation in comprehensive two-dimensional liquid chromatography of complex organic mixtures. This objective function is based on the concept of peak purity for one-dimensional liquid chromatography, which has been redefined for comprehensive two-dimensional liquid chromatography. The new CRF2D also includes other separation quality criteria, namely the number of two-dimensional peaks appearing in the chromatogram and the analysis time. The performance of the developed CRF2D was compared to an existing resolution metric, using simulated chromatograms. The capability of the new function to qualify the overall separation degree that it is attained under different chromatographic conditions was further assessed through a comprehensive two-dimensional liquid chromatography study of a mixture of four aromatic compounds. Finally, the knowledge obtained along this dissertation was used to develop a procedure to analyse three Portuguese red wine samples by comprehensive two-dimensional liquid chromatography coupled to a diode array and a fluorescence detectors, in order to obtain a two-dimensional chromatographic fingerprinting. The overall quality of chromatographic separation was quantified using the CRF2D, and the red wine samples were compared taking into account the obtained CRF2D values.