Sequential-injection stripping analysis of nifuroxime using DNA-modified glassy carbon electrodes.
The voltammetric behavior of nifuroxime was investigated comparing stationary voltammetric methods with the recently proposed sequential-injection stripping analysis (SISA), by using cyclic voltammetry (CV) and differential-pulse voltammetry at bare and DNA-modified glassy carbon (GC) electrodes. In cyclic voltammetry, reduction of nifuroxime at DNA-modified electrodes gives rise to a well-defined peak, and in contrast to bare GC surfaces, a re-oxidation peak could be observed. Optimization of the pre-concentration process at the DNA-modified surface led to a significant enhancement of the voltammetric current response, a better defined peak shape and an improved dynamic range. Based on this optimized voltammetric procedure, SISA has been evaluated for the determination of nifuroxime. The flow-system significantly facilitates the regeneration of the DNA-modified electrode surface, hence diminishing problems related to accumulation and memory effects. The linear detection range could be extended to 65 microM with a detection limit (3 s) of 0.68 microM, which corresponds to an absolute amount of 21 ng nifuroxime.
Diab
Nizam
N
Lehrstuhl fur Analytische Chemie, Ruhr-Universität Bochum, Universitatsstr 150, AG Elektroanalytik und Sensorik, D-44780 Bochum, Germany.
AbuZuhri
Ali
A
Schuhmann
Wolfgang
W
D015374:Biosensing Techniques; D002244:Carbon / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D009581:Nitrofurans / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012834:Silver; D018030:Silver Compounds; D013997:Time Factors
D009581:Nitrofurans; D018030:Silver Compounds; D012834:Silver; C073332:nifuroxime; D002244:Carbon; D004247:DNA; C037548:silver chloride