Development of an ELISA for the Determination of Amoxicillin in Water Samples
Alexander Ecke1,2 and Rudolf J. Schneider1,3
1Bundesanstalt für Materialforschung und -prüfung, Richard-Willstätter-Str. 11, 12489, Berlin, GER
2Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, GER
3Technische Universität Berlin, Straße des 17. Juni, 10623, Berlin, GER
Amoxicillin (AMX) is a -lactam antibiotic frequently used in the treatment of various infections caused by both gram-positive and gram-negative bacteria. Apart from the cleavage of the -lactam ring, AMX is excreted mainly unaltered by the medicated humans and animals and is thus released into the water cycle. Therefore, it can be found in several water bodies reaching from municipal effluent over surface and ground water to drinking water.
The main concern about the presence of antibiotics in water, especially in drinking water, is the evolution of antimicrobial resistance posing a severe health risk to humans and animals. In this context the Commission of the European Union has recently added AMX together with other antibiotics to the watch list of pharmaceutical compounds that should be monitored within water bodies in order to elucidate their distribution and evaluate the actual risk.
To date the methods of choice for the quantification of AMX in water samples are mass spectrometry based (HPLC or LC-MS/MS) due to their high accuracy and sensitivity. Nevertheless, they are expensive, immobile and time-consuming as they require sampling and sample preparation whereas immunoanalytical methods like ELISA (enzyme-linked immunosorbent assay) enable cheap and fast on-site analyses. Previously, ELISAs have already been used and reported for the determination of AMX in tissue and in lung secretions. 1 2
Herein we report the results for the development of an AMX-ELISA suitable to detect AMX in different water samples in the µg/L-range using commercially available anti-AMX antibody and AMX protein conjugates. Optimization of the assay conditions has been carried out as well as studies on the cross-reactivity of the antibody towards structurally similar -lactam antibiotics.