Application of directly coupled flame atomic absorption spectrometry-fast protein liquid chromatography to the determination of protein-bound metals

Abstract

The use of a new interface for directly coupled flame atomic absorption spectrometry-high-performance liquid chromatography is described for the determination of metals associated with various proteins. The proteins are first separated using fast protein liquid chromatography, the eluate then being transported as a series of discrete aliquots directly to the flame. The interface consists of eight platinum wire spirals mounted at 45° to each other on a rotating disc. The disc is turned to a number of pre-defined positions by a stepper motor. The complete interface is under microcomputer control, allowing the speed of rotation, stopping position and time in each location to be optimised. This allows complete compatibility between the interface and a wide range of eluate flow-rates. The potential application of this technique to clinical analysis is demonstrated by determinations of zinc, copper and cadmium in various proteins and zinc in blood plasma. Zinc was shown to be associated with the albumin and α₂-macroglobulin fractions in the plasma.