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Electrochemical detection of fluoroquinolone antibiotics in milk using a magneto immunosensor
Daniel G Pinacho1, Francisco Sánchez-Baeza2, María-Isabel Pividori3
1Nanobiotechnology for Diagnostics Group (Nb4D), IQAC-CSIC and CIBER de Bioingeniería, Biotemateriales y Nanomedicina, c/ Jordi Girona 18-26, 08034 Barcelona, Spain. daniel.gonzalez@iqac.csic.es.
Insights
A novel amperometric magneto-immunosensor (AMIS) detects fluoroquinolone antibiotic residues in milk. This method offers rapid, cost-effective, and on-site analysis without sample cleanup.
Area of Science:
- Analytical Chemistry
- Biosensors
- Food Safety
Background:
- Fluoroquinolone antibiotics are widely used in animal husbandry.
- Residues in milk pose risks to human health.
- Sensitive and rapid detection methods are needed.
Purpose of the Study:
- To develop a novel amperometric magneto-immunosensor (AMIS) for detecting fluoroquinolone residues in milk.
- To enable direct, on-site analysis without complex sample preparation.
- To achieve high sensitivity and broad applicability for multiple fluoroquinolones.
Main Methods:
- Utilized magnetic beads conjugated with a broad-spectrum anti-fluoroquinolone antibody.
- Employed a haptenized enzyme tracer and a magnetic graphite-epoxy composite (m-GEC) electrode.
- Integrated immunochemical reactions with electrochemical detection via magnetic capture.
Main Results:
- The AMIS successfully detected seven different fluoroquinolones in milk samples.
- Achieved high sensitivity, with limits of detection (LOD) as low as 0.009 µg/L for ciprofloxacin.
- Demonstrated quantitative measurement directly in milk, overcoming matrix interferences.
Conclusions:
- The developed AMIS provides a rapid, simple, and cost-effective solution for fluoroquinolone detection.
- This technology is promising for on-site screening of antibiotic residues in complex food matrices.
- The method facilitates compliance with regulatory limits (e.g., EU MRLs).
Abstract:
An amperometric magneto-immunosensor (AMIS) for the detection of residues of fluoroquinolone antibiotics in milk samples is described for the first time. The immunosensor presented combines magnetic beads biomodified with an antibody with a broad recognition profile of fluoroquinolones, a haptenized enzyme and a magnetic graphite-epoxy composite (m-GEC) electrode. After the immunochemical reaction with specific enzyme tracer, the antibody biomodified magnetic beads are easily captured by an electrode made of graphite-epoxy composite containing a magnet, which also acts as transducer for the electrochemical detection. In spite of the complexity of milk, the use of magnetic beads allows elimination of potential interferences caused by the matrix components; hence the AMIS could perform quantitative measurements, directly in these samples, without any additional sample cleanup or extraction step. The immunosensor is able to detect up to seven different fluoroquinolones far below the MRLs defined by the UE for milk; for example ciprofloxacin is detected directly in milk with an IC50 of 0.74 µg/L and a LOD of 0.009 µg/L. This strategy offers great promise for rapid, simple, cost-effective, and on-site analysis fluoroquinolones in complex samples.
