New Antibody and Immunoassay Pretreatment Strategy to Screen Polychlorinated Biphenyls in Korean Transformer Oil

Abstract

Development and modifications are described that expand the application of an immunoassay from the detection of Kanechlors (Japanese technical PCBs mixtures) to the detection of Aroclors (U. S. technical PCB mixtures, used in Korea) in contaminated Korean transformer oil. The first necessary modification was the development of a new antibody with a reactivity profile favorable for Aroclors. The second modification was the addition of a second column to the solidphase extraction method to reduce assay interference caused by the Korean oil matrix. The matrix interference is suspected to be caused by the presence of synthetic oils (or similar materials) present as contaminants. The modified assay was validated by comparison to high-resolution gas chromatography/high-resolution mass spectrometry analysis, and was shown to be tolerant of up to 10% of several common synthetic insulating oils. Finally the screening performance of the modified assay was evaluated using 500 used transformer oil samples of Korean origin, and was shown to have good performance in terms of false positive and false negative rates. This report provides evidence for the first establishment of immunoassay screening for Aroclor based PCB contamination in Korean transformer oil.

Label-Free Impedimetric Immunoassay for Trace Levels of Polychlorinated Biphenyls in Insulating Oil

“…The K d value against the PCBs calculated from the extrapolation to the zero antibody concentration was 0.43 μg/L (see Figure S-5B in the Supporting Information), and the K d values of three other antibodies previously reported to have high binding affinity were evaluated under the same conditions (Table ). The present antibody (RU6F9) had a higher binding affinity against a commercial mixtures of PCB than the other three antibodies, − and its binding affinity is to our knowledge the highest reported to date.…”

“…Furthermore, compared to the flow-based immunoassay system (KinExA) at near K d -limited measurement (antibody concentration; 50 pM), the impedimetric immunoassay achieved a wider detection range as shown in Figure B, which was the result of a noncompetitive antigen–antibody reaction and electrochemical measurement. The lower detection limit (LOD, 3σ) of 0.001 μg/L was at least 100-fold more sensitive than the antibody-based measurements reported to date, − ,− and it satisfied the 0.5 μg/L criterion of the environmental standard in Japan and the maximum contaminant level of drinking water set by the U.S. EPA.…”

“…Generally, immunoassays can simplify complicated analytical methods because of the specificity of the antibody for the target analyte. To date, several antibody-based analyses for PCBs in insulating oil, such as conventional ELISA and sensitive flow-based immunoassays, have been reported. − In particular, flow-based immunoassays using gold-labeled nanoparticles achieved a subppb level of commercial PCB detection (LOD; 0.1 μg/L) in aqueous solution and were useful for insulating oil analysis when combined with a simple cleanup procedure. , Although this method had an LOD of 0.1 mg/kg for total PCBs in insulating oil and simplified the conventional instrumental analysis, a complicated procedure was required for antibody labeling and 3 h of analysis time was required including the time spent for sample cleanup.…”

A Novel PCB77 Electrochemical Sensor Based on Nano-functionalized Electrode and Selected Aptamer

“…These above methods have some difficulties to meet the requirements of on-site detection of PCBs pollutants in physical environment because of the high cost of instruments, the complexity of sample processing and the highly trained technicians [9][10]. So far, some immunoassays for PCBs analysis are widely applied, such as enzyme linked immunosorbent assay (ELISA) [11] and antibody-based immunoassay [12], Although these methods have avoided the defects of the traditional methods and have a low detection limit, antibody acquire complicated, poor stabilit, and sensitive to environmental changes, thus, exploring some new sensitive, rapid and convenient methods for spot detection of PCBs is quite essential.…”