Differential pulse voltammetric determination and catalytic oxidation of sulfamethoxazole using [5,10,15,20‐ tetrakis (3‐methoxy‐4‐hydroxy phenyl) porphyrinato] Cu (II) modified carbon paste sensor

Abstract

Sulfamethoxazole (SM) is a sulfonamide bacteriostatic antibiotic. Its primary activity is against susceptible forms of streptococcus, staphylococcus aureus, escherichia coli, haemophilus influenzae, and oral anaerobes. It is commonly used to treat urinary tract infections. In addition it can be used as an alternative to amoxicillin-based antibiotics to treat sinusitis. It can also be used to treat toxoplasmosis. In the present work, a metalloporphyrin modified carbon paste sensor was fabricated and the electrochemical behaviour of SM was studied using differential pulse voltammetry (DPV). Cu (II) complex of 5,10,15,20- tetrakis (3-methoxy-4-hydroxy phenyl) porphyrin (TMHPP Cu (II)) was used as the active material. Compared with bare carbon paste electrode (CPE), the TMHPP Cu (II) modified CPE exhibits excellent enhancement effect on the electrochemical oxidation of SM. A well-defined oxidation peak of SM occurs at -140 mV in 0.1 M phosphate buffer solution (PBS) of pH 6. All the experimental parameters were optimized and it was found that under optimum conditions the oxidation peak current was linear to the concentration of SM in the range of 1.0 x 10(-2)-1.0 x 10(-8) M with a detection limit of 1.5 x 10(-9) M. The developed sensor has been successfully applied for the determination of SM in pharmaceutical formulations and urine sample.

Application of multiwalled carbon nanotubes/ionic liquid modified electrode for amperometric determination of sulfadiazine

“…Electrochemical detection methods have the advantage of being simple, low cost and easy to use . Up to now, modified electrodes, such as amperometric DNA‐peroxidase sensors, bismuth film electrodes, boron‐doped electrodes, carbon nanotube‐Nafion modified electrodes and metalloporphyrin modified electrodes, were designed for sulfonamide antibiotics determination. And the results show advantages of high determination sensitivity, good stability, and promising selectivity.…”

Analysis of sulfamethoxazole by square wave voltammetry using new carbon paste electrode

“…Figure 5A shows CV profiles of CPE in a blank solution of 0.04 mol L -1 BRbuffer (pH 2.18) and in the same solution containing 0.005 mol L -1 SMX, whereas Figure 5B shows CV profiles of glassy carbon in a blank solution of 0.05 mol L -1 s acid/methanol 70:3 (v/v) (pH 1.38) and in the same solution containing 0.005 mol L -1 SMX. An irreversible two-electron oxidation voltammetric peak appeared in both cases when 0.005 mol L -1 SMX was present in the solution [29,40]. Also, much lower background current that was obtained for the CPE as compared with the solid glassy carbon, suggests that the proposed CPE electrode could be more sensitive for SMX oxidation [6][7][8][9][10][11][12][13][14][15][16].…”

“…Hence the frequency of 12 Hz was chosen for further analysis because of the best resolution of the voltammetric peak ( Figure 6, peak (2)). According to the literature, the SMX electrochemical oxidation occurs at the primary amino groups (-NH2) [29,40]. Figure 7 illustrates the mechanism of SMX oxidation that as a two-electron and pH dependent reaction, possibly takes place in an acid medium.…”

“…Literature reveals that the supporting electrolyte plays an essential role in the voltammetric signal of SMX [29,[40][41][42]. Besides, the sulfa drugs have two dissociation constants (pKa), which in the case of the SMX correspond to the amino functional group with pKa value of 1.8 and amide functional group with a pKa value of 5.6 [29,33,37,40,44].…”

“…Besides, the sulfa drugs have two dissociation constants (pKa), which in the case of the SMX correspond to the amino functional group with pKa value of 1.8 and amide functional group with a pKa value of 5.6 [29,33,37,40,44]. Therefore the BRbuffer solution (0.04 mol L -1 in acetic, phosphoric and boric acids) (pH 2.18), with CV shown in Figure 4C was chosen as the experimental medium in the voltammetric studies of SMX.…”