Page:NIOSH Manual of Analytical Methods - 5027.pdf/3

 RIBAVIRIN: METHOD 5027, Issue 2, dated 15 August 1994 - Page 3 of 4 CALIBRATION AND QUALITY CONTROL: 8.

9.

10.

Calibrate daily with at least six working standards over the range 0.2 to 700 µg/mL. a. Add known amounts of calibration stock solution to mobile phase in 10-mL volumetric flasks and dilute to the mark. b. Analyze with samples and blanks (steps 11 through 13). c. Prepare calibration graph (peak area vs. µg Ribavirin). Determine recovery (R) at least once for each lot of filters used for sampling in the range of interest. Prepare three filters at each of five levels plus three media blanks. a. Deposit a known amount of Ribavirin onto the filter. Allow filters to air dry. b. Store samples overnight in the dark. c. Prepare (steps 5 through 7) and analyze with working standards. d. Prepare a graph of R vs. µg Ribavirin spiked. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and R graph are in control.

MEASUREMENT: 11. 12.

13.

Set liquid chromatograph system according to manufacturer's recommendations and to the conditions given on page 5027-1. Inject sample aliquot using syringe, fixed volume sample loop or autosampler. NOTE: If peak area is above linear range of calibration graph, dilute, reanalyze, and apply appropriate dilution factor in calculations. Measure peak area.

CALCULATIONS: 14. 15.

Determine the mass, µg (corrected for R) of Ribavirin found in the sample (W), and in the average media blank (B), from the calibration graph. Calculate concentration, C, of Ribavirin in the air volume sampled, V (L):

EVALUATION OF METHOD: This method is a modification of a bulk assay procedure developed by Eastman Kodak Company [3]. Measurement precision, Sr, was 0.057 with average recovery of 100% representing no bias, based on 16 samples ranging from 19.2 to 112 µg per filter. Sampling precision was not determined. The calibration curve was shown to be linear between 0.63 and 666 µg of Ribavirin/mL of extraction solution. A least-squares fit of the calibration curve yielded a limit of detection of 0.7 µg per filter and a limit of quantitation of 2 µg per filter [1,2].

REFERENCES: [1] [2] [3]

Belinky, Barry, "NIOSH/DPSE/MRSB Analytical Report for Ribavirin, Sequence #6138-B," (unpublished, 7/6/88). Belinky, Barry, "NIOSH/DPSE/MRSB Analytical Report for Ribavirin, Sequence #6138-A," (unpublished, 7/25/88). "Liquid Chromatographic Analysis of Ribavirin in Bulk Active Form," Eastman Kodak Company Internal Test Method, #KPAT-A-SS52956-LC-16-1, Rochester, New York (1985).

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