An ultra sensitive method for rapid in vitrocatalase assay with software based approach using LabVIEW virtual instrumentation

Abstract

A novel approach for estimation of catalase activity in biological samples was developed using real-time signal averaging with LabVIEW based virtual instrumentation. The assay was performed by on-line monitoring of the increase in dissolved oxygen concentration due to the catalytic reaction of the enzyme with its substrate H₂O₂ using a Clark type dissolved oxygen electrode. The electrode was interfaced with a computer using an op-amp based electronic circuit and LabVIEW based software for signal acquisition, data visualization and signal conditioning. Catalase activity in biological samples could be measured without pre-dilution and the method was not affected by interferences such as turbidity, viscosity and sample color. It was possible to increase the assay sensitivity from 0.5 U for the existing spectrophotometric method to 2.93 μU, with a sample size as little as 100 μl and response time as low as 9 s. Therefore, the proposed method shall find use in clinical assays, detection of pathogens and evaluation of catalase activity in cell cultures, neurological samples, milk and other food products.