Determination of vitamin C by a novel oscillating chemical system involving a tetraazamacrocyclic nickel complex

ANYL 53

Lin Hu, hulin21@hotmail.com1, Gang Hu, hugky@21cn.com2, Wei Yu2, and Hanhong Xu3. (1) Institute of Applied Chemistry, East China Jiaotong University, Nanchang, 330013, China, (2) Department of Chemistry, Anhui University, Hefei, 230039, China, (3) Key Lab of Pesticide and Chemical Biology, South China Agricultural University, Wu Shan Road, GuangZhou, 510642, China
An new method for the determination of vitamin C, via the perturbation caused by different amount of vitamin C on NaBrO3-Pyruvic acid-[NiL](ClO4 )2-H2SO4oscillating system, is proposed. The ligand L in the complex is an unsaturated tetraazamacracycle ligand, 5,7,7,12,14,14-hexemethyl-1,4,8,11-tetraazacyclotetradeca -4,11-diene. The amplitude of the potentiometric oscillation increases linearly in proportion to the logarithm of vitamin C concentration in the range of 3.0*10-6 - 2* 10-5 M, with a correlation coefficient of 0.9895 under the optimum conditions. The obtained relative standard deviation (RSD) for five measurements of 1.0*10-5 M vitamin C is 0.8 %. Some aspects of the potential mechanism of action of vitamin C on the oscillating chemical system are discussed. It is proposed that the vitamin C may be oxidized by the free radical BrO2, one of the intermediate of the oscillating reaction.
 

General Papers
7:00 PM-9:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Division of Analytical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006