Abstract:
Polychlorinated Biphenyls (PCBs) are a group of synthetic aromatic compounds which has been
used as thermal insulators and coolants in transformers, capacitors, motors and hydraulic systems
due to the high thermal capacity and also as stabilizers in the paint industry. The number and the
location of chlorine atoms in a PCB molecule determine many of its physical and chemical
properties. Despite its applications, PCBs are considered as persistent organic pollutants (POPs)
and they have been identified as carcinogenic to human and classified under the group 1 by the
International Agency for Research on Cancer (IARC). This study presents the validation data of
the method developed for analysis of Aroclor 1260 in transformer oils. The transformer oil
samples were prepared according to the ASTM D 4059 with few modifications and analyzed by
Gas Chromatography–Electron Capture Detection (GC-ECD) using HP 5 GC column (30
mx0.32 mm x0.25 μm) with a temperature programme starting from 100o C to 300o ̊C at a rate of
15o C min-1. The PCBs in transformer oils were extracted to 2,2,4-Trimethylpentane followed by
deactivated florisil cleanup. The study was performed under matrix matched condition to
eliminate the matrix effect that was found to be significant. The method was found linear over a
wide working range from 2.5-100 ppm and the linearity of the method was 0.994 with a lower
limit of determination of 2.5 ppm. The method shows satisfactory repeatability with relative
standard deviation below 7% over the entire working range. Accuracy of the method was assured
using spike recoveries at 5 ppm, 10 ppm and 50 ppm with 85%, 105% and 93% respectively.
The selectivity of Aroclor 1260 was confirmed against Aroclor 1254 and Aroclor 1242
considering uniquely identified non – overlapping chromatographic peaks with reference to the
standard reference materials (SRMs). Based on the performance characteristics, this method can
be suggested as an accurate and precise methodology to analyze Aroclor 1260 present in
transformer oil.
