DETERMINATION OF POLYCHLORINATED BIPHENYLS (PCB) IN INSULATING FLUIDS

Abstract

A comparative analysis of three methods of PCB determination in insulating fluids is carried out using capillary gas chromatography with a detection by electron capture (GC-ECD — IEC 61619:1997 »Insulating liquids – Contamination by polychlorinated biphenyls (PCB) – Method of determination by capillary column gas chromatography; EN 12766-2:2001 «Petroleum products and used oils – Determination of PCBs and related products»; FR 1.31.2012.13568 «Method for determination of sum of polychlorinated biphenyls and sum of polychlorinated terphenyls in mineral and synthetic oils, petroleum products and wastes by capillary column gas chromatography»). The first method requires determination of all the congeners in the analyzed sample and encounters the impossibility of their identification at the relatively low content of congeners and interfering impact of the impurities present in the used oils. The second method based on determination of six selected congeners (28, 52, 101, 153, 138, and 180) and subsequent multiplying of the sum of their contents by a factor of 5 is much better, but does not provide evaluation of the accuracy of the results thus obtained. The third method based on the use of technical products for calibration, and an arbitrary number of congeners distributed throughout the elution interval for determination of the content and type of the technical product occupies an intermediate position in comparison with the two previously considered methods and provides estimation of the uncertainty of the result. This method gives an intermediate result in comparison with the two previous ones and allows us to estimate the uncertainty of the result.