DIRECT DETERMINATION OF OXYGEN BY HPLC .2. CHAMBER AND SAMPLE APPLICATION SYSTEM FOR DETERMINATION OF O-2 AT TRACE LEVELS

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 samp le application (''two-chamber-siphon technique'') is presented which c an be used in combination with the previously reported chromatographic oxygen sensor (part 1). This new oxygen-sensing assay exhibits severa l advantages in comparison to conventional oxygen measurement systems: e.g., the uncontrollable influence of the surrounding atmosphere as w ell as oxygen consumption and storage processes are excluded, For the first time, measurements of molecular oxygen below 1 x 10(-7) mol L-1 can be performed, Reliable quantification of oxygen in liquids and als o in gaseous and solid samples can be achieved with utmost sensitivity (LOD 4.9 x 10(-9) mol L-1 O-2 = 98 fmol of oxygen on column) and prec ision (RSD = 0.7%, n = 8).