Differential Analysis of Blood Urea Using Combined Automated Ultrafiltration and Solid Phase Extraction in On-Line Series

Abstract

Solid phase extraction (SPE) is an efficient pretreatment method to separate a compound of interest in complicated matrix such as body fluid, food, or in soil. Ultrafiltration is also a suitable pretreatment method to remove higher molecular weight compounds such as protein in body fluid. The latter method is also useful for differential analysis of free type from protein-bound type compound in body fluid. Free type compound after ultrafiltration will exist in filtrate. Previously ultrafiltration and SPE were carried out off-line and the former was done manually, which was troublesome for routine analysis. In this paper these pretreatment methods were successfully on-line combined and controlled by computer first by the author. Unfortunately this kind of equipment is not currently available in the market yet due to patent restriction.