Page:NIOSH Manual of Analytical Methods - 3508.pdf/2

 METHYL ETHYL KETONE PEROXIDE: METHOD 3508, Issue 2, dated 15 August 1994 - Page 2 of 5 REAGENTS:

EQUIPMENT:

1. 2. 3. 4. 5. 6. 7. 8.

Acetic acid, glacial, reagent grade. Dimethyl phthalate (DMP), reagent grade. Water, distilled, deionized. Toluene. Methanol. Isopropyl alcohol, reagent grade. Sulfuric acid, conc. Diphenylcarbazide (DPC) solution, 0.25% (w/v). Dissolve 0.25 g ± 0.01 g reagent grade DPC in DMP in an Al foil-covered 100-mL volumetric flask. Agitate in ultrasonic bath to aid dissolution. Dilute to 100 mL. NOTE: This solution is light-sensitive. Prepare immediately before using. 9. Color reagent. Mix 30 mL 0.25% DPC solution with 20 mL glacial acetic acid. 10. Methyl ethyl ketone peroxide (MEKP), 60%, technical grade, in dimethyl phthalate. Standardize as in APPENDIX. 11. Calibration stock solution.* Pipet ca. 10 µL of 60% MEKP into a 50-mL pre-weighed volumetric flask. Accurately weigh the flask plus MEKP; dilute to the mark with dimethyl phthalate. Wrap flask in Al foil. Prepare in duplicate. 12. Sodium thiosulfate solution, 0.1 N, standardized. Commercially available, or prepare as in APPENDIX. 13. Sodium iodide solution, 20% (w/v). Dissolve 20 g sodium iodide in 100 mL methanol. 14. Sodium bisulfite. 15. Nochromix. 16. Dichlorodimethylsilane, 5% (w/v), in toluene (Sylon CT, or equivalent).



See SPECIAL PRECAUTIONS.

1. Sampler: glass midget impinger, 25-mL, silanized.* 2. Personal sampling pump, 0.5 to 2 L/min, with

SPECIAL PRECAUTIONS: MEKP is shock and heat sensitive. Store below 25 °C. MEKP solutions are extremely irritating and corrosive to the skin and eyes and may cause permanent eye injury. Use safety goggles. Dispose of waste MEKP solutions as follows: a. b. c.

Prepare 250 mL saturated aqueous sodium bisulfite in a 1-L beaker. Store in a hood. Add all waste solutions containing MEKP to this beaker. Allow to stand one week before disposing of the two-phase mixture.

__________________________________________ __________________________________________ ____ SAMPLING: 1.

Calibrate each personal sampling pump with a representative sampler in line. 2. Pipet 15 mL dimethyl phthalate into the impinger. Mark the level. Wrap with aluminum foil. 3. Sample at an accurately known flow rate between 0.5 and 2 L/min for a total sample size of 52 to 520 L. 4. Check liquid level in impinger and add dimethyl phthalate if necessary to bring level to 15.0 mL. Quantitatively transfer the contents of each impinger to a silanized, Al foil-wrapped vial and seal tightly. Quickly place in a cold chest. 5. Whenever possible, hand-deliver the samples packed in dry ice. Otherwise, ship samples in container with dry ice. Mark "FRAGILE" on the container. 6. Upon receipt in the laboratory, store vials in the freezer. Complete analysis as soon as possible.

SAMPLE PREPARATION: 7.

Adjust sample volume to 15.0 mL if necessary. Transfer in duplicate exactly 5.0 mL (1/3) of each sample or field blank to silanized test tubes.

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