A colloidal gold immunoassay strip assay for cadmium detection in oilfield chemicals

Cadmium ions (Cd²⁺) are some of the major pollutants in oilfield chemicals. To reduce the pollution of oilfield chemicals, it is necessary to detect and control the content of Cd²⁺. In this study, we synthesized a highly sensitive and specific monoclonal antibody against Cd²⁺ with an IC₅₀ of 1.97 ng mL^-1 and no cross-reactivity. Based on this antibody, a colloidal gold immunoassay strip detection assay with an IC₅₀ of 1 mg kg^-1 and a detection range of 1.0-20 mg kg^-1 in oilfield chemicals was developed. This assay could be completed in 20 min and can be used for Cd²⁺ on-site testing in oilfield chemicals and improve supervision efficiency in oil exploration and development.