Amperometric ascorbic acid sensor based on doped ferrites nanoparticles modified glassy carbon paste electrode.

In this study, a novel electrochemical sensor for quantification of ascorbic acid with amperometric detection in physiological conditions was constructed. For this purpose, cobalt and nickel ferrites were synthesized using microwave and ultrasound assistance, characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRPD), and used for modification of glassy carbon paste electrode (GCPE). It was shown that introducing these nanoparticles to the structure of GCPE led to increasing analytical performance. Co ferrite modified GCPE (CoFeGCPE) showed better characteristics toward ascorbic acid sensing. The limit of detection (LOD) obtained by sensor was calculated to be 0.0270 mg/L, with linear range from 0.1758 to 2.6010 mg/L. This sensor was successfully applied for practical analysis, and the obtained results demonstrated that the proposed procedure could be a promising replacement for the conventional electrode materials and time-consuming and expensive separation methods.

Surgical site infection incidence and risk factors in thoracic surgical procedures: A 12-year prospective cohort study.

INTRODUCTION: Surgical site infections (SSI) continue to be a major problem for thoracic surgery patients. We aimed to determine incidence rate (IR) and risk factors for SSI in patients with thoracic surgical procedures. METHODOLOGY: During 12 years of hospital surveillance of patients with thoracic surgical procedures, we prospectively identified SSI. Patients with SSI were compared with patients without SSI. RESULTS: We operated 3,370 patients and 205 (6.1%) developed SSI postoperatively. We detected 190 SSI among open thoracic surgical procedures (IR 7.1%) and 15 SSI after video-assisted thoracic surgery (IR 2.1%). Five independent risk factors for SSI were identified: wound contamination (p = 0.013; relative risk (RR) 2.496; 95%, confidence interval (CI): 1.208-5.156), American Society of Anesthesiologist (ASA) score (p = 0.012; RR: 1.795; 95% CI: 1.136-2.834), duration of drainage (p < 0.001; RR: 1.117; 95% CI: 1.085-1.150), age (p = 0.036; RR: 1.018; 95% CI: 1.001-1.035) and duration of operation (p < 0.001; RR:1.005; 95% CI:1.002-1.008). CONCLUSION: The results are valuable in documenting risk factors for SSI in patients undergoing thoracic surgery. The knowledge and prevention of controllable risk factors is necessary in order to reduce the incidence of SSI.

Effect of cobalt doping level of ferrites in enhancing sensitivity of analytical performances of carbon paste electrode for simultaneous determination of catechol and hydroquinone.

This work presents the simultaneous determination of catechol (CC) and hydroquinone (HQ), employing a modified carbon paste electrode (CPE) with ferrite nanomaterial. Ferrite nanomaterial was doped with different amount of cobalt and this was investigated toward simultaneous oxidation of CC and HQ. It was shown that this modification strongly increases electrochemical characteristics of the CPE. Also, electrocatalytic activity of such materials strongly depends on the level of substituted Co in the ferrite nanoparticles. The modified electrodes, labeled as CoFerrite/CPE, showed two pairs of well-defined redox peaks for the electrochemical processes of catechol and hydroquinone. Involving of ferrite material in the structure of CPE, cause increase in the potentials differences between redox couples of the investigated compounds, accompanied with increases in peaks currents. Several important parameters were optimized and calibration curves, with limits of detection (LOD) of 0.15 and 0.3µM for catechol and hydroquinone, respectively, were constructed by employing amperometric detection. Effect of possible interfering compounds was also studied, and proposed method was successfully applied for CC and HQ quantification in real samples.