PARENT SESSION
1A Chemical, biological, and combined methods for the detection of pollutants
9:00 AM to 7:00 PM, Wednesday, 09 May 2001

(W/EH038) The Determination of Polychlorinated Biphenyl Compounds in Electrical Insulating Oils by Enzyme Immunoassay.

Setford, Steven¹, Saini, Selwayan¹, ¹

ABSTRACT- There is increasing global concern regarding the utilisation and discharge of polychlorinated biphenyl (PCB) compounds into the environment. PCBs are a class of organo-halide that are routinely used as additives in various oil-based preparations and are important in the manufacture of products as diverse as plastics to pesticides. The ubiquitous nature of these materials coupled to their toxicity and recalcitrant nature has led to significant interest in the development of simple, rapid and low-cost methods for their analysis in a wide range of environmental matrices. Consequent to this, we report the development and performance of a competitive indirect immunoassay for the quantitative measurement of PCBs in insulating oils. Reagent preparation and the assay characterisation, optimisation and validation steps are described. The dynamic range of the assay for Aroclors 1254 and 1260 in methanol was 30-1000 ng/mL with 50% signal inhibition values of 217 and 212 ng/mL respectively. Impending legislation in the UK is likely to decree that oils containing >50 microgramme per mL PCB be considered contaminated. Assay sensitivity increased with the degree of PCB chlorination. The assay of structurally related compounds of environmental concern yielded cross-reactivity values of under 0.6%. The immunoassay proved reliable for the analysis of diluted transformer oils containing >35 microgrammes per mL PCB (neat) but over-estimated PCB levels in diluted oils containing <10 microgrammes per mL of neat analyte. The oils requiring pre-treatment using either solid-phase extraction techniques or washing with KOH-ethanol/sulphuric acid to remove matrix interferents. The analytical performance of the assay compared favourably against a commercially available semi-quantitative immunoassay kit for PCBs in soil and water.

Key words: PCB, Immunoassay, Insulation oil, Regulation