Bioassay of phenol disinfectants by flow microcalorimetry.

A rapid flow microcalorimetric method for the bioassay of phenol disinfectants is described. The assay may be used for phenol within the range 50-80 mM with a reproducibility of +/- 2%. Assay results on other phenols examined indicate the range of the assay. Commercial disinfectants may be assayed directly (the flow microcalorimetric technique makes no demands for optical clarity nor absence of suspended material on the solutions used) with the same reproducibility. An in-use concentration of the chosen disinfectant may be selected from the experimental data since the flow microcalorimetric output permits "time-to-death' of the test organism to be observed directly.