Abstract
The determination of chlortetracycline, doxycycline, oxytetracycline, and tetracycline in milk samples by HPLC coupled to a cucurbit[8]uril-based potentiometric sensor is herein presented. The new tetracycline-selective electrode is based on a polymeric membrane incorporating cucurbit[8]uril as a macrocyclic host, potassium tetrakis(p-chlorophenyl) borate as an ionic additive, 2-fluorophenyl 2-nitrophenyl ether as a plasticizer, and multi-walled carbon nanotubes as nanostructured materials. A microfluidic wall-jet flow-cell is implemented as a potentiometric detector after chromatographic separation by a C8 column using a gradient mobile phase of sulphuric acid and acetonitrile. The proposed methodology was validated following International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) and European Union (EU) guidelines. Linear regression models provided R2 in the range from 0.9973 ± 0.0026 to 0.9987 ± 0.0012 for all tetracycline antibiotics. The limits of detection and quantification ranged from 13.3 to 46.0 μg L−1 and 44.4 to 92.1 μg L−1, respectively. Precision intra-day, inter-day, and inter-electrode showed relative standard deviation values lower than 12.5%, 13.5%, and 12.9%, respectively. Accuracy was assessed by analysis of spiked milk samples around the maximum residue limit, yielding recovery values in the range from 81.3 to 108.5%. The simple, sensitive, cost-effective, and reliable HPLC-ion-selective electrode method justifies its use as a competitive alternative for the analysis of tetracycline residues in the food quality control sector.
Highlights
Accepted: 1 March 2022Tetracycline antibiotics (TCs) are broad-spectrum pharmaceutical drugs that exhibit activity against a wide range of microorganisms [1]
The consumption of low-level doses for long periods induces the selective predominance of drug-resistant microorganisms with time, which puts public health in jeopardy [6]
The potentiometric response of conventionally shaped electrodes prepared with different membranes was firstly evaluated towards four different TCs in batch conditions
Summary
Tetracycline antibiotics (TCs) are broad-spectrum pharmaceutical drugs that exhibit activity against a wide range of microorganisms [1]. The low toxicity profile and low cost enhance their extensive use as veterinary drugs for the prevention and treatment of several microbial diseases [2] as well as growth promoters in intensive animal farming [3]. This widespread use of TCs may cause the presence of residues in foods of animal origin, whose intake result in harmful effects on human health such as allergic reactions, gastrointestinal disturbance, liver damage, poor fetal development, and pigmentation of teeth [4,5]. The MRLs for TCs residues, according to the US Food and Drug Administration (FDA), are 2 mg kg−1 in muscle, 6 mg kg−1 in the liver, and 0.3 mg kg−1 in milk [7], whereas the Codex Alimentarius Commission of the FAO/WHO has adopted MRLs of Published: 3 March 2022
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
