Biomimetic sensor based on MnIIIMnII complex as manganese peroxidase mimetic for determination of rutin

A novel biomimetic sensor for rutin determination based on a dinuclear complex [Mn(III)Mn(II)(Ldtb)(mu-OAc)(2)]BPh(4) containing an unsymmetrical dinucleating ligand, 2-[N,N-bis(2-pyridylmethyl)-aminomethyl]-6-[N-(3,5-di-tert-butyl-2-oxidoben-zyl)-N-(2-pyridylamino)aminomethyl]-4-methylphenol (H(2)Ldtb), as a manganese peroxidase mimetic was developed. Several parameters were investigated to evaluate the performance of the biomimetic sensor obtained after the incorporation of the dinuclear complex in a carbon paste. The best performance was obtained in 75:15:10% (w/w/w) of the graphite powder:Nujol:Mn(III)Mn(II) complex, 0.1 mol L(-1) phosphate buffer solution (pH 6.0) and 4.0x10(-5) mol L(-1) hydrogen peroxide. The response of the sensor towards rutin concentration was linear using square wave voltammetry in the range of 9.99x10(-7) to 6.54x10(-5) mol L(-1) (r=0.9998) with a detection limit of 1.75x10(-7) mol L(-1). The recovery study performed with pharmaceuticals ranged from 96.6% to 103.2% and the relative standard deviation was 1.85% for a solution containing 1.0x10(-3) mol L(-1) rutin (n=6). The lifetime of this biomimetic sensor was 200 days (at least 750 determinations). The results obtained for rutin in pharmaceuticals using the biomimetic sensor and those obtained with the official method are in agreement at the 95% confidence level.