National Institute for Occupational Safety and Health

“ Desorption efficiency studies as performed by OSHA [1] using 6 samples at 3 levels gave a recovery of 99.0% for DETA, 99.2% for EDA, and 99.8% for TETA. The recovery of DETA, EDA, and TETA from samples used in a 15-day storage study was 89, 94, and 91%, respectively. These samples were generated by spiking the amines onto a glass wool plug in front of a sampling tube and drawing approximately 10 liters of air at 80% relative humidity through them. A 30-day storage study conducted by NIOSH [2] showed similar recoveries. ”

“ Calibrate daily with at least five working standards in the range of the samples. a. Prepare working standards by serial dilution of the stock standards with DMF. b. Analyze together with samples, blanks, and QC samples (steps 12 and 13) . c. Prepare separate calibration graph (peak area vs. μg per sample) for EDA, DETA, and TETA. Determine the desorption efficiency (DE) at least once for each lot of XAD-2 resin used for sampling. Prepare three tubes at each of five levels plus 3 media blanks. a. Inject a known amount of analyte onto the NTIC-coated resin. b. Allow to stand overnight. ”

“ PREPARATION OF NTIC-COATED XAD-2 RESIN: a. Weigh sufficient XAD-2 resin (16/50 mesh) to allow preparation of tubes for sampling, blanks, quality control, and recovery studies. (@ 120 mg XAD resin per tube) . b. Dissolve sufficient 1-naphthylisothiocyanate in methylene chloride to coat the XAD-2 resin at a 10% loading (w/w) . c. Place the XAD-2 resin in the NTIC solution, mix, and remove methylene chloride using rotary evaporation. d. Load the coated XAD-2 resin into 7 cm long, 6-mm OD, 4-mm ID, glass tubes so that the front section contains 80 mg and the back section contains 40 mg. ”