Electrochemical behavior and determination of cefradine at a pencil graphite electrode
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Date
2026
Authors
Bogdanović, Anđelija
Tasić, Žaklina
Petrović Mihajlović, Marija
Simonović, Ana
Radovanović, Milan
Antonijević, Milan
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Publisher
Institute of General and Physical Chemistry, Belgrade, Serbia
Source
Book of abstracts - First International Conference on Medical, Pharmaceutical and Cosmetic Chemistry, Household and Industrial Chemistry, Forensic and Analytical Chemistry - ChemInno 2026, 5 May 2026, Belgrade, Serbia
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Abstract
Cephalosporins are a group of β-lactam antibiotics derived from 7-aminocephalosporanic acid (7-ACA). They have a broad spectrum of antibacterial activity and are widely used to treat various bacterial infections in both human and veterinary medicine (1). Cephradine, a first-generation cephalosporin, acts by inhibiting bacterial cell wall synthesis. Cephalosporins are susceptible to hydrolysis in surface water systems, especially under alkaline conditions. They tend to form complexes with cations and accumulate in wastewater sediments. They enter aquatic systems primarily from industrial and manufacturing facilities, which are their main source. Other sources are more difficult to identify because antibiotics undergo structural and compositional changes over time after entering the environment. Intensive use of β-lactam antibiotics in livestock and aquaculture often leads to low concentrations of antibiotic residues in food products and by-products. First-generation cephalosporins, such as cephradine and cefadroxil, can reach high concentrations in urine after ingestion of contaminated food. Antibiotic residues pose a potential risk to human health and contribute to environmental imbalance when released into ecosystems. Such contamination may negatively affect aquatic organisms and promote the spread of resistant bacterial strains. Given these challenges, accurate and sensitive detection of β-lactam antibiotics in complex environmental and food samples is essential. Such detection is necessary to ensure food safety, monitor environmental pollution, and implement regulatory standards. Traditional analytical and optical methods, such as high-performance liquid chromatography (HPLC), liquid chromatography–mass spectrometry (LC-MS), and UV-Vis spectrophotometry, offer high accuracy in antibiotic determination. However, these methods are expensive, require laboratory conditions, and involve complex, time-consuming sample preparation procedures, limiting their use for rapid on-site analysis. They also often require organic solvents that may harm the environment. Due to these limitations, electrochemical techniques and sensors are increasingly used. Electrochemical methods are faster, more efficient, more sensitive, simpler, and more cost-effective. They allow the detection of low concentrations of antibiotics in small sample volumes. These techniques measure electrical parameters such as current or potential and correlate them with the presence of specific chemical species in the sample. The main electrochemical methods for antibiotic detection include amperometry/potentiometry, voltammetry, and electrochemical impedance spectroscopy. Various electrochemical sensors have been used to detect cephalosporins, employing different electrolytes and buffer solutions depending on the analyte and method. The choice of electrode significantly affects the sensitivity and selectivity of the method. Commonly used electrodes include mercury electrodes, glassy carbon electrodes, and electrodes modified with nanomaterials, while Britton-Robinson and phosphate buffers are frequently used as supporting media. These methods have been successfully applied to the analysis of real samples, including serum and other clinical specimens. The choice of medium influences the shape, intensity, and position of the voltammetric peak. The electrochemical behavior of cephalosporins is often studied in buffers of different pH values, as acidity or alkalinity can affect the reaction mechanism and electrochemical activity of the analyte. Britton-Robinson buffer is used over a wide pH range, while phosphate buffer (PBS) is suitable for certain cephalosporins, such as cefotaxime. In some cases, acidic or alkaline media are used to induce degradation of cephalosporins and form electroactive products, enabling indirect detection of compounds that do not exhibit a significant electrochemical signal (3). In this study, the electrochemical detection of ephradine was investigated using differential pulse voltammetry (DPV). The effects of concentration and electrolyte pH were examined. A Pencil graphite electrode served as the working electrode, a saturated calomel electrode (SCE) as the reference electrode, and a platinum electrode as the counter electrode. The pH 7.5 solution was prepared by mixing BR buffer with 0.1 M NaOH. The effect of concentration was studied in Britton-Robinson (BR) buffer at pH 2, using concentrations of 2 × 10⁻⁵, 5 × 10⁻⁵, and 6 × 10⁻⁵ mol/L (Figure 1.). The results showed that increasing concentration led to higher peak currents, with the highest peak observed at 6 × 10⁻⁵ mol/L. All voltammograms displayed a well-defined peak at approximately E ≈ 1.0–1.1 V. As the concentration decreased, the peak current also decreased, while the peak potential remained nearly unchanged. These results indicate a concentration-dependent oxidation process without changes in the reaction mechanism.
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Scopus
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ISBN
978-86-908815-2-9
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ARR