National Institute for Occupational Safety and Health

“ Add water to the 15-mL mark.
CALIBRATION AND QUALITY CONTROL: 5.
Calibrate daily with at least six working standards over the range 3 to 150 μg TMTU per sample. a. Pipet 0- to 10-mL aliquots of calibration stock solution into clean vials. Bring the total volume to 15 mL with distilled water.
NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition, 8/15/94 TETRAMETHYL THIOUREA: METHOD 3505, Issue 2, dated 15 August 1994 - Page 3 of 4 b. c.
Analyze together with the samples and blanks (steps 6 through 8) . Prepare calibration graph (absorbance vs. μg TMTU) . ”

“ Wear gloves and handle only in a hood. Tetramethyl thiourea is an animal teratogen and carcinogen [3] . Avoid inhalation, ingestion or skin contact. Keep TMTU in a bottle labelled "animal carcinogen" and place the bottle in a resealable thick-walled plastic bag in locked storage.
SAMPLING: 1. 2. 3.
Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 0.2 and 1 L/min for a total sample size of 50 to 250 L. Transfer the sample solution to a 20-mL vial for shipment. Collect a high-volume air sample or rafter dust sample. ”