Page:NIOSH Manual of Analytical Methods - 1006.pdf/3

 FLUOROTRICHLOROMETHANE: METHOD 1006, Issue 2, dated 15 August 1994 - Page 3 of 4 CALIBRATION AND QUALITY CONTROL: 9.

10.

11.

Calibrate daily with at least five working standards over the range 0.01 to 40 mg fluorotrichloromethane per sample. Use serial dilutions for the smallest concentrations. a. Add 5.0 mL eluent to each of a series of vials. Attach septum with crimp seal to each vial. b. Weigh each vial. c. Inject amounts (2 to 30 µL) of neat liquid fluorotrichloromethane (or of a standard solution in CS 2) into the vials. d. Reweigh the vials. Calculate the mass of fluorotrichloromethane added. e. Analyze with samples and blanks (steps 12 and 13). f. Prepare calibration graph (ratio of peak area of analyte to peak area of internal standard vs. mg fluorotrichloromethane). Determine desorption efficiency (DE) at least once for each lot of charcoal used for sampling in the range of interest. Prepare three tubes at each of five levels plus three media blanks. a. Add 400 mg charcoal (e.g., an unused front section) to each of a series of vials. b. Seal each vial with a septum and crimp seal. c. Weigh each vial. d. Inject amounts (2 to 30 µL) of neat fluorotrichloromethane (or of a standard solution in CS 2) into the vials. e. Reweigh each vial. Calculate the mass of fluorotrichloromethane added. Allow to stand overnight. f. Desorb (steps 6 through 8) and analyze with freshly prepared working standards (steps 12 and 13). g. Prepare a graph of DE vs. mg fluorotrichloromethane recovered. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and DE graph are in control.

MEASUREMENT: 12.

13.

Set gas chromatograph according to manufacturer's recommendations and to conditions given on page 1006-1. Inject sample aliquot manually using solvent flush technique or with autosampler. NOTE 1: tr = 3 min for fluorotrichloromethane and 4.5 min for nonane under these conditions. NOTE 2: If peak area is above the linear range of the working standards, dilute an aliquot of the desorbed liquid with eluent, reanalyze, and apply the appropriate dilution factor in calculations. Measure peak area. Divide the peak area of analyte by the peak area of internal standard on the same chromatogram.

CALCULATIONS: 14.

15.

Determine the mass, mg (corrected for DE), of fluorotrichloromethane found in the sample front (W f) and back (W b) sorbent tubes, and in the average media blank front (B f) and back (B b) sorbent tubes. NOTE: If W b > W f/10, report breakthrough and possible sample loss. Calculate concentration, C, of fluorotrichloromethane in the air volume sampled, V (L):

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94