Establishment of an immunoassay for detection of nonylphenols in surfactant oilfield chemicals based on computer-aided design.

Nonylphenols (NPs) are confirmed endocrine disruptors that are banned in many countries due to correlations with human cancers. NPs pollution in surfactant oilfield chemicals (OFCs) has become an important environmental safety issue. It is significant to establish a simple, accurate and low-cost method for detection of NPs in OFCs. In this research, computer-aided molecular design technology was utilized to design NPs haptens. High affinity monoclonal antibodies against NPs were obtained using a matrix effect-enhanced screening method, with an IC value of 183.01 ng/mL. A colloidal gold immunochromatography assay (ICA) for detection of NPs enabled rapid on-site detection of large volumes of OFCs. Under optimal conditions, the limit of detection was 0.72-1.82 mg/kg, with a detection range of 4.49-191.28 mg/kg. The recovery was 84 %-104 %, with coefficients of variation < 13 %. As confirmed by high-performance liquid chromatography of natural positive OFCs samples, the proposed colloidal gold ICA demonstrated accuracy and reliability, with potential for fast and economical on field test.