No abstract

The present study introduces a novel electrode for rapid, highly sensitive, and selective electrochemical sensor for cadmium(II) using 5% N1-hydroxy-N1,N2-diphenylbenzamidine (HDPBA) modified carbon paste electrode (CPE) (HDPBA‒CPE). Surface characterizations and structural analysis of the proposed HDPBA‒CPE were performed using several analytical techniques. The voltammetric measurements of Cd(II) were conducted by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). Several experimental conditions such as composition and pH of buffer solutions, HDPBA composition, accumulation potential and time, and other voltammetric conditions were optimized. Cd(II) was preconcentrated on the modified electrode surface for 270 s using Britton Robinson (B-R) buffer (0.1 M, pH 4) at −1.0 V versus Ag/AgCl, followed by electrochemical oxidation of the accumulated Cd(II) in the positive scan of SWASV after a quiet time of 10 s. Under optimized parameters, the proposed method showed a linear range of 0.3–100 nM Cd(II) with a detection limit of 0.032 nM. The fabricated HDPBA-modified carbon paste electrode exhibited excellent sensitivity, selectivity, stability, and reproducibility (with RSD of 3.8%). The developed HDPBA‒CPE was used for the quantification of Cd(II) in tobacco and environmental water samples, and it was found to be applicable for the determination of different types of real samples.

Mercury is a highly toxic metal, of which even small doses (<200 ng mL−1) can cause serious problems for humans, plants, animals and microorganisms, including marine species and freshwater organisms. Hence, a simple, fast, highly selective and sensitive and accurate method for the detection of mercury in the environmental, clinical or biological samples is necessary. A new, sensitive and selective method for the determination of Hg(II) with 5 % N1‐hydroxy‐N1,N2‐diphenylbenzamidine modified carbon paste electrode has been developed. Hg(II) was accumulated for 210 s on the surface of the modified electrode using 0.1 M CH3COONa of pH 7 at −0.8 V vs Ag/AgCl, followed by electrochemical stripping with SWASV in 0.1 M NH4Cl at pH 4. The linear range is 0.02–10 μM Hg(II) with limit of detection of 1.28 nM. The method has RSDs of 3.7 %. The method was applied for the determination Hg(II) in five types of water samples. The recoveries were in the range 97.8–103 %. The proposed method was found to be highly selective and sensitive and has many attractive features compared to previous reports such as low cost, simplicity of electrode preparation, long term stability, fast response, easy renewable ability, and reasonable short accumulation time.

This study was conducted in and around Yabello, Southern Ethiopia, with the objective of determining the prevalence of poultry coccidiosis and its associated risk factors. Faecal samples were collected from total of 384 chickens. Floatation technique was used to detect coccidian oocyst. The result revealed that out of 384 chickens, 74 were positive to coccidiosis and overall prevalence was 19.3%. The frequency of detection of oocyst in the faecal samples from exotic and local breed chicken were 18 and 20.4%, respectively. The result of the current study disclosed that the prevalence of coccidiosis was almost similar in female (19.6%) and male (18.2 %) chickens. The prevalence rates of 18.4 and 21.9% were recorded in chicken grouped under the age category of 2-8 weeks (young) and greater than 8 weeks (adult), respectively. The prevalence rates of 21.6 and 18% were also recorded in good and poor body condition, respectively. Furthermore, coccidiosis occurrence in intensive and extensive management system were 22.1 and 16.7%, respectively. In conclusion, even though the difference for all risk factors was statistically insignificant (p>0.05), the study showed that coccidiosis is important disease of poultry in Yabello district, Southern Ethiopia and this is an indication for intervention to tackle the disease without any priority within the risk factors.

This paper presents a new modified carbon paste electrode with N1-hydroxy-N1,N2-diphenylbenzamidine and multi-walled carbon nanotubes for highly sensitive and selective determination of Cu(ii) usingsquare wave anodic stripping voltammetry technique.