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 1,1,2,2-TETRABROMOETHANE: METHOD 2003, Issue 2, dated 15 August 1994 - Page 4 of 4 EVALUATION OF METHOD: Method S117 [2] was evaluated with controlled atmospheres of 1,1,2,2-tetrabromoethane [1]. Overall precision ( SˆrT) was 0.096 for 98-L samples (18 samples, pooled) at 6.5 to 23 mg/m 3. Concentrations found by this method, 6.5, 14 and 23 mg/m 3, were 7, 4 and 17% lower than the corresponding concentrations based on the delivery rate of the syringe pump and flow rates of dilution air in the generation system. The discrepancies were attributed to difficulties in generating the atmospheres. Breakthrough from front sections of sorbent was not observed during passage of 220 L of dry air at 0.9 L/min when the concentration was 23 mg/m 3. Breakthrough at high relative humidity was not tested. Portions of silica gel were fortified with solutions of 1,1,2,2-tetrabromoethane in hexane. Average values of desorption efficiency were 0.79, 0.92 and 0.98 after applications of 0.70-, 1.4- and 2.8-mg quantities of 1,1,2,2-tetrabromoethane; precision ( Sˆr) was 0.041 (18 samples, pooled). A storage study to determine the stability of 1,1,2,2-tetrabromoethane on silica gel was not performed. Peroxides in tetrahydrofuran may cause rapid deterioration of standard solutions of 1,1,2,2-tetrabromoethane; thus, standards should be prepared daily.

REFERENCES: [1] Documentation of the NIOSH Validation Tests, S117, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-185 (1977), available as GPO Stock #017-033-00231-2 from Superintendent of Documents, Washington, DC 20402. [2] NIOSH Manual of Analytical Methods, 2nd ed., Vol. 2, S117, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-B (1977). [3] NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, Acetylene Tetrabromide, U.S. Department of Health and Human Services, Publ. (NIOSH) 81-123 (1981), available as GPO Stock [4] Tucker, S. P., and G. J. Deye. Anal. Lett., 14 (A12), 959-976 (1981).
 * 1) 017-033-00337-8 from Superintendent of Documents, Washington, DC 20402.

METHOD REVISED BY: Samuel P. Tucker, Ph.D., NIOSH/DPSE; S117 originally validated under NIOSH Contract CDC-99-74-45.

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