National Institute for Occupational Safety and Health

“ Calibrate daily with at least six working standards over the range 10 to 900 μg TPP per sample. a. Add know amounts of calibration stock solution to cover the range of interest to 10.0-mL volumetric flasks and dilute to the mark with diethyl ether. b. Analyze working standards together with samples and blanks (steps 11 and 12) . c. Prepare a calibration graph of peak area vs. μg of triphenyl phosphate per 10-mL sample. Determine recovery for each lot of filters used for sampling in the concentration range of interest. Prepare three filters at each of five levels plus three media blanks. ”

“ Calculate concentration (C) of triphenyl phosphate in the volume of air sampled, V (L) :
EVALUATION OF METHOD:
This method was evaluated over the range of 1.25 to 6.99 mg/m 3 at an atmospheric temperature and pressure of 24 °C and 759 mm Hg, using a 100-L sample. Overall sampling and measurement precision, SrT, was 0.066, with average recovery of 99.1%, representing a non-significant bias. Recovery of triphenyl phosphate from filters was 99.3% for an air sample concentration of 7.0 mg/m 3 at 1.5 L/min for 66 minutes. [1,3] . A storage stability study was not conducted. ”

“ Spike aliquot of calibration solution onto each filter. b. After air-drying, extract filters in 10 mL diethyl ether (steps 5 through 7) . c. Analyze together with working standards. NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition, 8/15/94
10. d. Prepare graph of recovery vs. μg triphenyl phosphate per sample.
Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration and recovery graphs are in control. ”