Measuring hydrogen peroxide due to water radiolysis using a modified horseradish peroxidase based biosensor as an alternative dosimetry method

• H2O2 generates between 20 nM at 0.5 Gy and 110 nM at 10 Gy during water radiolysis.
• Designed biosensor can successfully detect H2O2 at concentration less than 1200 nM.
• Responses of designed biosensor are linear from 0.5 Gy to 5 Gy of absorbed doses.
• Sensitivity and detection limit of biosensor are 260 nA/Gy and 0.392 Gy, respectively.
• Our study indicates that responses of fabricated biosensor are reliable at least for a month.

H2O2 generated during water radiolysis was measured electrochemically as an alternative dosimetry method. A biosensor was fabricated by immobilising modified horseradish peroxidase (HRP) on a glassy carbon electrode (GCE) followed by evaluation of its analytical parameters. Anthraquinone 2-carboxylic acid was used to modify HRP. To assess sensor performance, phosphate buffer solutions were irradiated with 0.510 Gy of gamma ray emitted from 60Co. The results showed that this sensor can detect low quantities of hydrogen peroxide in water radiolysis. Sensitivity, detection limit and linear range of the biosensor were 260 nA/Gy, 0.392 Gy and 0.5–5 Gy, respectively. Long term stability studies showed that sensor responses were stable for at least a month. The cathodic peak current, as biosensor response, subsequently decreased to 20% of its initial value.