Research On The Fabrication And Properties Of Antibacterial Drugs Electrochemical Sensors

Antibiotics are one of the great achivement of the human. They hold an importentrole in human healthy and safity. Antibiotics have been widely used to treat peopleand animal diseases and promote animal growth. However, the misuse of thesemedicines may have some adverse affects, such as allergic reactions and antibioticresistance. Therefore, sensitive and selective methods for their determination inbiological fluids are highly advisable. A series of analytical methods have beenreported for the determination of antibiotics.Among these methods, electrochemicalmethod has been widely accepted due to the advantages of considerable simplicity,quick response and low cost. The electrochemical sensors are used to study theelectrochemical propoties and electrode reaction mechanism and thereupon establishselective, simple and precise quantification analytical method. In this paper, weprepared different modified electrodes for the analysis of antibiotics includingofloxacin, norfloxacin, ciprofloxacin, gatifloxacin, cefotaxime and nevirapine, whichhas been summarized as follows:1. A novel cysteic acid modified carbon paste electrode (Cysteic acid/CPE) based onelectrochemical oxidation of L-cysteine was developed to simultaneously determineofloxacin and gatifloxacin in the presence of sodium dodecyl benzene sulfonate(SDBS). Fourier transform infrared spectra (FTIR) indicated that L-cysteine wasoxidated to cysteic acid. Electrochemical impedance spectroscopy (EIS) and cyclicvoltammograms (CV) indicated that cysteic acid was successfully modified onelectrode. The large peak separation (116mV) between ofloxacin and gatifloxacinwas obtained on cysteic acid/CPE while only one oxidation peak was found on bareelectrode. And the peak currents increased5times compared to bare electrode.Moreover, the current could be further enhanced in the presence of an anionicsurfactant, sodium dodecyl benzene sulfonate. The differential pulse voltammograms(DPV) exhibited that the oxidation peak currents were linearly proportional to their concentrations in the range of0.06–10μM for ofloxacin and0.02–200μM forgatifloxacin, and the detection limits of ofloxacin and gatifloxacin were0.02μM and0.01μM (S/N=3), respectively. This proposed method was successfully applied todetermine ofloxacin and gatifloxacin in pharmaceutical formulations and humanserum samples.2. An electrochemical sensor for fluoroquinolones (FQs) based on polymerization ofβ-cyclodextrin (β-CD) and L-arginine (L-arg) modified carbon paste electrode (CPE)(P-β-CD-L-arg/CPE) was built for the first time. Synergistic effect of L-arg andβ-CD was used to construct this sensor for quantification of these importantantibiotics. Scanning electron microscope (SEM) image shows that polymer of β-CDand L-arg has been successfully modified on electrode. Electrochemical impedancespectroscopy (EIS) and cyclic voltammograms (CV) further indicate that polymer ofβ-CD and L-arg efficiently decreased the charge transfer resistance value ofelectrode and improved the electron transfer kinetic between analyte and electrode.Under the optimized conditions, this modified electrode was utilized to determinethe concentrations of ciprofloxacin, ofloxacin, norfloxacin and gatifloxacin. Thedifferential pulse voltammograms (DPV) exhibits the oxidation peak currents werelinearly proportional to their concentration in the range of0.05–100μM forciprofloxacin,0.1–100μM for ofloxacin,0.1–40μM for norfloxacin and0.06–100μM for gatifloxacin, respectively. This method was also successfully used todetect the concentrations of each drug in pharmaceutical formulations and humanserum samples. In addition, this proposed fluoroquinolones sensor exhibited goodreproducibility, long-term stability and fast current response.3. A simple and sensitive electrochemical sensor based on Au nanoparticles/poly(L-arginine) modified carbon paste electrode (AuNPs/Parg/CPE) was constructedand utilized to determine cefotaxime. Scanning electron microscope (SEM) imageshowed that the L-arginine (L-arg) had been electropolymerized on the CPE and theimmobilized Au nanoparticles (AuNPs) were spherical in shape. Fourier transform infrared spectra (FTIR) indicated that the Poly (L-arginine)(Parg) film wassuccessfully modified on CPE. Electrochemical impedance spectroscopy (EIS) andcyclic voltammogram (CV) illustrated the Parg and AuNPs efficiently decreased thecharge transfer resistance value of electrode and improved the electron transferkinetic between analytes and electrode. The electrooxidation of cefotaxime on themodified electrode was performed by cyclic voltammetry (CV) and linear sweepvoltammetry (LSV). The results showed the response current of cefotaxime atAuNPs/Parg/CPE increased17times than that of bare CPE. The calibration curvewas linear over the cefotaxime concentration range of0.01–100.0μM with adetection limit (S/N=3) of2.3nM. This proposed method has been applied todetermine cefotaxime in pharmaceutical formulations and human serum samples,and the results were satisfactory.4. A novel uracil covalently grafted carbon paste electrode (Ura/CPE) based onelectro-deposition of uracil on CPE was prepared for the quantitative determinationof nevirapine. The records of electrochemical impedance spectroscopy (EIS) andcyclic voltammograms (CV) in K3Fe(CN)6/K4Fe(CN)6solution illustrated that uracilgrafted on CPE efficiently decreased the charge transfer resistance value of electrodeand improved the electron transfer kinetic between analyte and electrode. Theelectrochemical properties of Ura/CPE towards the oxidation of nevirapine wereinvestigated by cyclic voltammetry and differential pulse voltammetry (DPV) in0.1M NaOH. The effects of pH and scan rates on the oxidation of nevirapine werestudied. The results indicated the participation of the same protons and electrons inthe oxidation of nevirapine, and the electrochemical reaction of nevirapine onUra/CPE is an adsorption-controlled process. Under optimized conditions, thelinearity between the oxidation peak current and nevirapine concentration wasobtained in the range of0.1–70.0μM with detection limit of0.05μM and thesensitivity of2073μA·mM–1·cm–2(S/N=3). The proposed method was alsosuccessfully applied to detect the concentration of nevirapine in human serum samples.5. A new chiral recognition of alanine enantiomers sensor was built based on chiralmesopores polypyrrole modified on glass carbon electrode. chiral mesoporespolypyrrole was prepared by using N-myristoyl-L-alanine to be chiral lipid ribbontemplating and "seeding" route. SEM image illustrated the the morphology of chiralmesopores polypyrrole was helical structure. This material was modified on theelectrode to recognize the alanine enantiomers in solution. The result wassatisfactory.