FORMIC ACID: METHOD 2011, Issue 1, dated 15 August 1994 - Page 4 of 4 REFERENCES: [1] NIOSH Manual of Analytical Methods, 2nd. ed., Vol. 5, S173, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-175 (1978). [2] Backup Data Report for Formic Acid, prepared under NIOSH Contract No. 210-76-0123. [3] User Check of OSHA ID112/NIOSH modification of NIOSH Method #7903, NIOSH Sequences
- 7077-J, 7078-K, (unpublished October, 1990).
METHOD REVISED BY: George Y. Williamson, MRSB, DPSE.
APPENDIX A: DESORPTION EFFICIENCY STOCK SOLUTION, 51.5 mg FORMIC ACID/mL Pipet 6 mL of 88% formic acid into a 125-mL volumetric flask. Make to volume with dioxane. For standardization, appropriate aliquots are withdrawn, diluted with deionized water, and analyzed as in steps 9 through 15. NOTE: The solution must be prepared fresh daily. Loss of formic acid was observed after 24 h. Pipetting below the liquid level of the standard will minimize loss of formic acid from evaporation. APPENDIX B: SAMPLING TUBE PREPARATION Silica gel cleaning procedure: Add 500 to 600 mL deionized water, slowly and with stirring, to ca. 200 mL volume of silica gel in 1-L beaker. When exothermal reaction has subsided, heat in boiling waterbath for ca. 30 min with occasional stirring. Decant and rinse four to five times with deionized water. Repeat cleaning procedure and dry overnight in 100 °C oven until free flowing. If blank of silica gel shows impurities, repeat cleaning procedure. Silica gel tubes: Pack glass tubes, 7-mm OD, 4.8-mm ID, 11 cm long, with 400 mg of 20/40 mesh washed silica gel in front section and 200 mg backup section. Use urethane foam plugs between sorbent sections and at back end. Hold front section in place with 6-mm diameter, 1-mm thick glass fiber filter plug (Gelman 66088).
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
