2. Experimental
2.1. Materials
Chemicals required for the preparation of 0.2Mphosphate buffer solution
(PBS) and SDS were purchased from MERCK. Graphite powder
and paraffin oilwere also purchased fromMERCK andwere used as substrate
and pasting liquid, respectively for the preparation of carbon
paste electrode. Standard solutions of BPR were prepared daily in distilled
water. BPR was supplied from a local pharmacy (Mehr Darou
Pharmaceutical Company).