Convenient and sensitive colorimetric determination of alendronate sodium with Ce4+-triggered oxidation of TMB

Abstract

As alternatives to nanozymes, some metal ions have been used in chemical/biochemical sensors owing to their facile acquisition avoiding tedious preparation and purification. Ce⁴⁺ has been reported to possess oxidase-like activity. Ascribed to its strong oxidative ability, Ce⁴⁺ can trigger the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to its blue product oxTMB without the requirement of H₂O₂. When ALDS is added, the oxidation ability of Ce⁴⁺ can be reduced because of the redox reaction between Ce⁴⁺ and ALDS. The absorbance intensity ascribed to oxTMB decreases followed by the fading of the solution. On the basis of such a mechanism, a simple method is proposed for monitoring ALDS in two linear ranges of 0.1–10.0 μM and 10.0–60.0 μM. The detection limit is low to 0.05 μM. Furthermore, this method exhibits great potential for ALDS detection in real biological body fluids and pharmaceutical samples.