An evaluation of the use of a pH indicator for the detection of beta-lactamase in enzyme immunoassay.
The use of a mixed pH indicator containing bromocresol purple and bromothymol blue was evaluated for the detection of beta-lactamase activity in enzyme immunoassays (EIA) based on this enzyme. The EIA was found to correlate well with a bioassay for antibodies to tetanus toxoid in sheep sera. Results could be read spectrophotometrically at 450 nm or visually as a colour change from dark blue to yellow. The mixed pH indicator was found to have a number of desirable features including good stability, ease of preparation and a sharp colour change which makes the system suitable for visual determination of titration end points.
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D001962:Bromcresol Purple; D001979:Bromthymol Blue; D003017:Clostridium tetani / Q000276:immunology; D006863:Hydrogen-Ion Concentration; D007124:Immunoenzyme Techniques; D012756:Sheep; D013053:Spectrophotometry; D001618:beta-Lactamases / Q000032:analysis*
D000907:Antibodies, Bacterial; D001962:Bromcresol Purple; D001618:beta-Lactamases; D001979:Bromthymol Blue