Recovery of 125I-thyroxine and ribonuclease solutes

Adsorption losses onto surfaces of complex solutes functioning as analytes or reagents in chemical analysis eventually become a major problem as the amount of solute decreases to lower levels. This problem is one of the most important ones now facing ultratrace (below the ng level) organic and biological analysis. A better understanding and control of adsorption losses of ultratrace solutes onto surfaces is needed. This thesis investigates the recovery of two representative complex solutes from surfaces. The first solute is 125I-thyroxine, which is subjected to a soluble affinity chromatography technique potentially useful for sample cleanup at the ultratrace level. The recovery of 125I-thyroxine at the low pg level as a model analyte is optimized throughout several steps. Ribonuclease is the second ultratrace solute investigated with emphasis on the preparation and characterization of carrier ribonuclease as an inactive analog of the native enzyme. This carrier ribonuclease is successful, allowing an assay for ribonuclease to be extended from the mid to low pg level. The usefulness of this reagent is limited, however, by the presence of residual trace ribonuclease that itself has novel properties and is also characterized