Page:NIOSH Manual of Analytical Methods - 3505.pdf/4

 TETRAMETHYL THIOUREA: METHOD 3505, Issue 2, dated 15 August 1994 - Page 4 of 4 APPENDIX: PREPARATION OF COMPLEXING REAGENT 1. Weigh 0.500 g Na 2Fe(CN) 5NO·2H 2O in a 50-mL beaker. Dissolve in 10 mL distilled water. 2. Grind together 0.500 g NH 2OH·HCl and 1.00 g NaHCO 3 in a mortar. 3. In a hood, add the ground mixture to the solution from step 1 above. When bubbling ceases, add 0.10 mL bromine. When reaction stops, add ca. 10 mL distilled water. Filter. Rinse beaker with 4 mL distilled water and filter. Transfer filtrate to a 25-mL volumetric flask and dilute with distilled water to the mark. Refrigerate.

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