A graphene-based chemiluminescence resonance energy transfer immunoassay for detection of phenothiazines in pig urine

In this study, a homogeneous competitive immunoassay based on graphene and chemiluminescence resonance energy transfer was first reported to detect small molecule substance. A generic monoclonal antibody of phenothiazine drugs was coupled to graphene as the recognition element and energy acceptor. The composite, the HRP-labeled hapten and the analyte solution were added into the microplate wells to perform homogeneous competition. Then luminol-H2O2-4-(imidazol-1-yl)phenol system was added to initiate light emission, and the light signal was positive correlation with the analyte concentration. After optimization of several parameters, the method was used to determine the residues of 4 phenothiazines in pig urine. Results showed that one assay was finished within 10 min, and the limits of detection for the 4 drugs were in the range of 2.0–5.0 pg/mL. Their recoveries from the standards fortified blank urine sample were in the range of 81.5%–96.8%. Therefore, this method could be used as a simple, rapid, and sensitive tool for routine screening the residues of phenothiazines in pig urine.