Comparison between Amperometric and Chemiluminescence methods in detection and dosimetry of cobalt-60 gamma ray emission

Hydrogen peroxide (H2O2), produced by gamma ray irradiation to watery solution, was used as an analytical parameter for dosimetry of cobalt-60 (60Co) radiation. Detection of the produced H2O2 was carried out using two an amperometric biosensor fabricated by immobilization of anthraquinone 2-carboxylic acid modified horseradish peroxidase on glassy carbon electrode, and chemiluminescence technique using luminol as a fluorophore and diperiodatocuprate as a catalyst. In the first method, at the applied potential of -550 mV (vs. Ag/AgCl) the biosensor showed the sensitivity of 74.46 nA/Gray and detection limit of 0.061 Gray (R.S.D=3.67% for N=3) towards H2O2 produced by 60Co. In the second method, the sensitivity and detection limit for 60Co gamma ray was determined to be 2.34 (luminescence intensity/Gray) and 0.069 Gray (R.S.D=4.16% for N=3), respectively. The obtained results revealed that both proposed techniques, with leaner range from 0.25 to 5 Grays are applicable for detection and dosimetry of gamma ray from 60Co.