National Institute for Occupational Safety and Health

“ This method uses 13-mm glass fiber filters which have not been evaluated for collecting PCB. In Method S120, however, Aroclor 1242 was completely recovered from 37-mm glass fiber filters using 15 mL isooctane [8,13,14] . With 5 mL of hexane, Aroclor 1016 was also completely recovered from 100mg Florisil beds after one-day storage [1] . Thus, with no adsorption effect likely on glass fiber filters for PCB, 5 mL hexane should be adequate to completely extract PCB from combined filters and front sorbent sections. Sample stability on glass fiber filters has not been investigated. ”

“ Transfer the glass fiber filters to 7-mL vials. Cap the Florisil tubes with plastic (not rubber) caps and pack securely for shipment.
SAMPLE PREPARATION: 5. 6. 7.
Place the glass wool and 100-mg Florisil bed in the same 7-mL vial in which the filter was stored. Add 5.0 mL hexane. In a 4-mL vial, place the 50-mg Florisil bed including the two urethane plugs. Add 2.0 mL hexane. Allow to stand 20 min with occasional agitation. ”

“ Calibrate daily with at least six working standards over the range 10 to 500 ng/mL PCB. a. Add known amounts of stock standard solution to hexane in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 11 and 12) . c. Prepare calibration graph (sum of areas of selected peaks vs. ng PCB per sample) . Determine desorption efficiency (DE) at least once for each lot of glass fiber filters and Florisil used for sampling in the calibration range (step 8) . Prepare three tubes at each of five levels plus three media blanks. a. ”