Chapter 8 - Analytical Techniques for High Mass Materials: Method Development

Abstract

This chapter considers analytical methods able to characterize molecules, which lie beyond the range of standard techniques. It focuses on materials with masses greater than 500μ, contained in tars and extracts from coal or biomass as well as crude oil and its fractions. Standard molecules are not normally available for such materials. The chapter presents an outline of the developments in bulk methods for mass estimation, starting with size exclusion chromatography. The technique has been used for examining mass distributions of predominantly aromatic materials and is calibrated by using standard compounds and polymers of many different types. Following this, it describes mass spectrometric methods likely to ionize and detect materials with molecular masses above the m/z 500μ range. These methods are usually coupled to chromatographic fractionation and involve several different combinations of sample introduction (liquid chromatography, supercritical fluid chromatography, thin layer chromatography) and ionization techniques. The latter include desorption chemical ionization (DCI), field ionization (FI), field desorption (FD), fast atom bombardment (FAB), plasma desorption (PD), matrix assisted laser desorption/ionization MALDI- and laser desorption (LD) mass spectrometry and electrospray ionization (ESI). Finally, the chapter presents an analysis of trace metal elements using inductively coupled plasma mass spectrometry (ICP-MS).