Direct Determination of Oxygen by HPLC. 2. Chamber and Sample Application System for Determination of 0↓（2） at Trace Levels

摘要

All oxygen measurement systems so far available are characterized by a lack of suitable precision and/or required limit of detection, which would be essential for a great variety of applications. In this paper, a novel oxygen chamber together with a completely new concept of sample application ("two-chamber-siphon technique") is presented which can be used in combination with the previously reported chromatographic oxygen sensor (part 1). This new oxygen-sensing assay exhibits several advantages in comparison to conventional oxygen measurement systems: e.g., the uncontrollable influence of the surrounding atmosphere as well as oxygen consumption and storage processes are excluded. For the first time, measurements of molecular oxygen below 1×10↑(－7) mol L↑(－1) can be performed. Reliable quantification of oxygen in liquids and also in gaseous aid solid samples can be achieved with utmost sensitivity (LOD 4.9×10↑(－9) mol L↑(－1) O↓(2) = 98 fmol of oxygen on column) and precision (RSD = 0.7%, n = 8).