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Analysis of PCB's in Transformer Oil Pamela Edwards, Altex Scientific Detection ol part-per-million levels ot polychlorinated biphenyls (PCB's) is important because ot the health hazards these compounds present. PCB's were used lor many years as cooling-lubricants in transformers without knowledge of their toxic effects.: The Improper handling ol PCB's during That lime has contributed to a situation where PCB's can be found in waste water, fish products, soil, and in oil which has replaced PCB's In transformers. The analysis of PCB's in transformer oil depends In part on the limits the U.S. Environmental Protection Agency has es tablished At the time of this writing, the limits dictate that materials containing 50 ppm PCB's or more are subject to strict disposal regulations. Thus, a sensitive analytics! method is necessary to deter mine the level of PCB's. Several recent arti cles describing both gas chromatographic (GLC) and liquid chromatographic (HPLC) methods have been published. However, these reported procedures require time consuming sample preparation.'?-3 The HPLC method described in this report eliminates the need for tedious sample preparation by using a detector which is specific for chemical species such as PCB's. This method requires only filtration as sample preparation and is sensitive enough to detect 1-2 ppm of PCB's. Materials and Methods. All HPLC work was done on a Model 332 system, con sisting of two 110A pumps, a 420 mi croprocessor/controller and a 210 injection valve with a 20 /ul loop. The detector was a Tracor 965 photoconductivity detector with a zinc lamp. An Ultrasphere ODS (250 mm x 4.6 mm) column was used for analysis. A C-R1A Integrator was used to plot and analyze detector output signal. Acetonitrile (MeCN) and isopropanol (IPA) were obtained from Burdick and Jackson. A mobile phase of 56% IPA, 14% MeCN and 30% water was used lot all analyses at a flow rate of 1 -ml/min. PCB standards, clean transformer oil, and transformer oils contaminated with PCB's were obtained Irom industry. Sample prep aration consisted of filtering the oil sam ples through a 0.45 micron fitter before injection. Results and Discussion. A chiomatogram of the PCB standard, Aroclor 1242, in MeCN Is shown in Figure 1. In Figure 2 a separation of the same standard at the same concentration, 100 ppm, dissolved in clean transformer oil is shown. Because it is the total amount ol PCB's which is L Figure 1. Photoconductivity chromatogram of standard Aroclof 1242 in acetonitrile Sample volume was 20 /*! and total concentration of PCB's was 100 ppm. Figure 2 Photoconductivity chromatogram ol standard Aioclor 1242 made uo in clean translotmer oil to a total PCB concentratron ol tOO ppm j T fit l Bn.tp.>V'. ^ \ *!<*. ^ 1 : Tut Figure 3 Photoconductivity chromatogram of 20 /ul clean transformer oil Figure 4 Photoconductivity chiomatogram of 20 **t of dirty transformer oil containing more than 100 ppm PCB`s. Figure 5. Photoconduclivity chromatogram of 20 //1 of translotmer oil containing small amounts of PCB's 6 required, not amounts of individual compo nents. complete separation ot all compo nents is not critical. "Fingerprint" chromato grams of PCB's which can be quantified by a grouping system is adequate It is apparent that injecting the oil directly reduces resolution of individual compo nents but does not prevent quantifying total PCB's. To insure that the transformer oil contained no substances which would show up using the photoconductivity detector, a blank injection was made. No significant peaks are present in the chro matogram of clean oil shown in Figure 3 The solvent front may be due to dissolved gas in the sample Several samples of dirty transformer oil were also analyzed. A chromatogram ol an oil sample which obviously contains more than 50 ppm PCB's and would be subject to the EPA regulations is shown in Figure 4 Quantification ol the PCB's in this sample would have been quite simple using a grouped/external standard technique A dirty oil which does not contain high levels ol PCB's is shown in Figure 5. By compar ing this chromatogram to those in Figures 1 and 3, it is clear that the peaks at 6.53 and 7.68 minutes represent small amounts 01 PCB's. The photoconductivity detector is also sensitive to nitrosamines, sultonated organics, and polybrominated biphenyls which are on occasion also found in transformer oils. To eliminate concerns that these compounds might be coeluting with the PCB's, fractions were collected from a dirty oil analysis and were analyzed by GCMS. The results of the GC-MS indicated the presence of polynuclear aromatics and other organic compounds None ol the lat ter compounds would have been detected by the photoconductivity detector. The instrumentation and methods de scribed here for analyzing PCB's in transformer oil have advantages compared to other methods in that very little sample preparation is needed for specific detec tion with more than adequate sensitivity (1 2 ppm) tor EPA regulations Acknowledgement. The author wishes to acknowledge Paul Kelly of Finnegan Instruments lor the assistance with the GCMS analysis, and Michael Minner of the City of Tacoma Sewer Utility Division, Washington, for the PCB standards and samples BIBLIOGRAPHY 1. Klimisch, H.M. and Ingeonghtson, DM, Anal Chem. 52, II, 1675-8 (1980) 2. Ogata JN., Okun. J.D., Hylin. JW.. and Bevenue, A,, J Chromalogr. 189(31. 425-7 (1980) 3. Belliardo, F,, Gionchiglia, E and Nano, G M, J Liq. Chromatogr 2(1), 77-83 (1979) DSW 033351 STLCOPCB4017313