Photooxidation assisted sensitive detection of trace Mn2+ in tea by NH2-MIL-125 (Ti) modified carbon paste electrode

NH2-MIL-125(Ti), as a highly porous titanium-based MOF, has been firstly reported to show an efficient photooxidation activity toward Mn2+ in pH 8.5 NH3-NH4Cl (0.04 M) buffer under visible light. Mn2+ was detected quantitatively by cathodic stripping voltammetric method based on the oxidized manganese product. The stripping peak currents on NH2-MIL-1 25(Ti)/CPE was linearly proportional to the concentration of Mn2+ in the range from 1.0 x 10(-8) to 1.0 x 10(-5) M with the detection limit of 4.0 10-9 M. This method has been successfully applied for the detection of Mn2+ in tea samples, and the results were in close agreements with those obtained by atomic absorption spectroscopic method. (C) 2014 Elsevier B.V. All rights reserved.