Approaches to the Determination of Chemical Species in Biological Materials

Abstract

Living systems exist in dynamic equilibrium, wherein levels and interconversions between different chemical species is constantly changing. To gain information regarding the biological function and utilization of these chemical species, a concerted collaborative effort using a wide variety of techniques and disciplines is required. At present most analyses of chemical species rely upon in vitro measurements, which must then be used to extrapolate to real-time measurements of the fluctuation of these species in vivo. Analytical approaches to the determination of chemical species generally include various separation techniques followed by specific spectroscopic methodologies to quantitate the trace element content of the separated fractions. A number of specific studies have covered a wide range of separation and atomic detection techniques. Applications of molecular spectroscopic techniques, which have been limited due to sensitivity, can give a great deal of information on the chemical species itself rather than just quantitation of the metal content. These molecular techniques may be rejuvenated in the future due to significant advances in sensitivity combined with continuous flow analysis techniques capable of very rapid, high-precision, low blank-level, and multisample analyses. Use of biocatalytic and ion-sensitive microelectrodes for in vivo determination of chemical species has considerable promise for relatively noninvasive measurements in single cells. Further development and use of computer simulation models of equilibria in human blood plasma between a number of trace elements with naturally occurring and administered chelating agents will be very beneficial to an understanding of these complex systems. The growing awareness of the important multiple roles of trace elements in human health has led to increased medical-clinical interest in diagnosis and therapy involving specific chemical species of these elements.