Characterization of biologically important volatile and non-volatile molecules via heteroatom determination using chromatography and mass spectrometry.

摘要

Interest in molecule specific characterization of metal and metalloid containing species within a biological system is gaining importance in recent years. This not only facilitates the establishment of toxic or beneficial effects of certain form of elements, but in certain cases paves way to understanding of biotransformation of elements and also helps to assess the fate of the environmental contaminants within a biological system. Coupled techniques involving hyphenation of separation methods such as high performance liquid chromatography and gas chromatography with element/molecule specific detection has become the most powerful tool in determination of metal(loid) containing species. Heteroatom determination using mass spectrometric techniques such as inductively coupled plasma mass spectrometry (based on element selective detection) and others such as ESI, EI and MALDI (based on element specific isotope patterns) have been used for the complete characterization of the species of interest. Heteroelements such as selenium, iodine and phosphorus are known to be important atoms in a wide variety of molecules of biological interest ranging from small volatiles and non-volatile amino acids to the macromolecules such as proteins. The aim of this dissertation is characterization of such species in various complex matrices using the above techniques. These include determination and identification of selenium containing amino acids in green onions, characterization of iodine containing species in commercially available seaweeds, studying the novel selenium volatiles in the green onions and localization of the high molecular weight selenium containing species in the mung bean sprouts. On the basis of the results, conclusions are drawn about their chemical association with biological molecules, both micro (volatile and non-volatile forms), macro molecules and their metabolites in the studied system. Another aspect of this dissertation is method development for the fast and sensitive determination of anthropogenic molecules such as phosphorus containing fire retardants/plasticizer so that their fate from the plastic material to the blood plasma can be studied.