Oxygraphic profiles of stressed bovine blood in a temperature controlled 2 ml reactor vessel provide the basis for an investigation of blood's response to various conditions. This response is broken down into an initial response (within 3 seconds), the response over 1 hour and the response over 24 hours. Fast-assay runs which investigate the initial response display a dose-response relationship when chemically stressed by phenol. Phenol concentrations in the 1,000 ppm range indicate a decrease in dissolved oxygen (DO) and higher phenol concentrations of over 20,000 an increase in DO. In addition to phenol concentration, other factors investigated with respect to the initial response are the effects of temperature, blood amount, DO before blood is added, blood age, blood blood aeration, addition of 1-butanol, and handling stress.

Long term response profiles for blood exposed to phenol or other stresses (such as decreased osmotic pressure or increased temperature); indicate the existence of oxygraphic activity in the form of molecular oxygen peaks (MOPs). A technique is presented which summarizes the activity of these long term response profiles conveniently
with a single number in micrograms O2/ml packed cells. Also, attempts to predict the appearance of MOPs based on oxygraphic profiles, and, separately, on pH, are presented.

The effect on the DO consumption rate, during the first hour of the run, of osmotic stress, blood amount, phenol concentration is also explored. The oxygraph, traditionally used by enzymologists to investigate enzyme kinetics through observation of DO, has potential applications in developing toxicity assays for xenobiotics.

Key words: bovine blood, oxygen concentration, xenobiotic, molecular oxygen peak, phenol, MOP