ARS | Publication request: Simultaneous determination of 13 fluoroquinolone and 22 sulfonamide residues in milk by a dual-colorimetric enzyme-linked immunosorbent assay

Submitted to: Analytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 24, 2013
Publication Date: January 24, 2013
Citation: Jiang, W., Wang, Z., Beier, R.C., Jiang, H., Wu, Y., Shen, J. 2013. Simultaneous determination of 13 fluoroquinolone and 22 sulfonamide residues in milk by a dual-colorimetric enzyme-linked immunosorbent assay. Analytical Chemistry. 85:1995-1999.

Interpretive Summary: Enzyme-linked immunosorbent assays (ELISAs) usually focus on the detection of a single analyte or a single group of analytes. An ELISA is an easy-to-use test and is similar to the commonly used over-the-counter pregnancy tests. In this study, we focused on determining analytes from two distinct groups of chemicals, fluoroquinolone and sulfonamide antibiotic residues. Both the fluoroquinolones and sulfonamides are widely used in humans, as well as in food-producing animals to control disease. Here, we used an antibody specific for each set of antibiotics in the same analysis. Antibodies are substances that are produced by the immune system in response to foreign substances which enter the body. Once the antibodies to a foreign substance are isolated, they can be used in a method to detect the presence of that foreign substance. Two different enzymes were used to label the two different antibodies, thus providing marker chemicals having two different wavelengths of detection. The developed immunoassay is suitable for high-throughput screening of these low-molecular weight contaminants and allows the simultaneous detection of the two different sets of antimicrobial compounds during the same milk sample analysis.

Technical Abstract: Enzyme-linked immunosorbent assays (ELISAs) usually focus on the detection of a single analyte or a single group of analytes, e.g., fluoroquinolones or sulfonamides. However, it is often necessary to simultaneously monitor the two classes of antimicrobial residues in different food matrices. In this paper, we describe a dual-colorimetric ELISA for simultaneous detection of 13 fluoroquinolone and 22 sulfonamide residues. The limit of detection for fluoroquinolones and sulfonamides was 2.4 ng/mL and 5.8 ng/mL, respectively. The developed immunoassay is suitable for high-throughput screening of these low-molecular weight contaminants. This is the first report where two different enzymes (alkaline phosphatase and horseradish peroxidase) were used in one immunoassay and together in a single well for simultaneous detection of multiple low-molecular weight chemical residues.