Trace Detection of Ampicillin and Influencing Factors Using an Optical Biosensor

The development of an assay for trace detection of ampicillin using an optical biosensor based on surface plasmon resonance (SPR) is reported. The biospecific interactions between ampicillin and ampicillin monoclonal antibody were monitored in real time. Water solution with a series ampicillin concentration is detected. The analysis time per sample was less than 10 minutes. Furthermore, the influencing factors including flow velocity and temperature are discussed in detail in order to get the best conditions and ensure the effectiveness and high accuracy of the method. The limit of detection (LOD) of the assay for ampicillin is 1.25 ng/ml, which is below the EU´s maximum residue limit (MRL) of 4 ppb. Therefore, the application of optical biosensor technology in antibiotic residues analysis is of great interest.