How is PCB contamination quantified in transformer oil samples?

Quantification is done by laboratory analysis that reports PCB concentration as ppm or mg per kg. The lab method identifies either total PCBs or specific mixtures and applies calibration curves to convert detector response into numeric concentration. Multiple runs and quality checks ensure accuracy. The reported concentration is compared against regulatory thresholds that classify oil as non PCB, low level contaminated, or PCB containing. This classification directly affects storage, transport requirements, and disposal options during maintenance or retirement.