Methyl Ethyl Ketone (2500)
METHYL ETHYL KETONE CH3 COCH2 CH3
MW: 72.11
METHOD: 2500, Issue 2
CAS: 78-93-3
EVALUATION: FULL
OSHA : 200 ppm NIOSH: 200 ppm: STEL 300 ppm ACGIH: 200 ppm: STEL 300 ppm (1 ppm = 2.95 mg/m3 @ NTP)
PROPERTIES:
2500
RTECS: EL6475000 Issue 1: 15 February 1984 Issue 2: Rev., 15 May 1996 liquid; d 0.805 g/mL @ 20 °C; BP 79.6 °C; MP ! 86 °C; VP 13 kPa (100 mm Hg; 13% v/v) @ 25 °C; explosive range 2 to 10% v/v in air
SYNONYMS: 2-butanone; MEK
SAMPLING SAMPLER:
SOLID SORBENT TUBE (beaded carbon, ~150 mg/~75 mg)
FLOW RATE:
0.01 to 0.2 L/min
VOL-MIN: -MAX:
0.25 L @ 200 ppm 12 L
SHIPMENT:
routine
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
methyl ethyl ketone (MEK)
DESORPTION:
1 mL CS2 ; stand 30 min
INJECTION VOLUME:
5 :L
SAMPLE STABILITY:
at least 90 days @ - 5 °C [1]
TEMPERATURE-INJECTION: -DETECTOR: -COLUMN:
BLANKS:
2 to 10 field blanks per set
CARRIER GAS:
N2 or He, 25 mL/min
COLUMN:
glass or stainless steel, 4 m x 2-mm ID; 20% SP-2100/0.1% Carbowax 1500 on Supelcoport 100/120
CALIBRATION:
MEK solutions in CS 2
RANGE:
0.15 to 5 mg per sample
ACCURACY RANGE STUDIED:
75 to 2250 mg/m3 [1]
BIAS:
not significant [1]
OVERALL PRECISION (Ö r T ):
0.038 [1]
ACCURACY:
± 7.4%
250 °C 300 °C 55 to 75 °C
ESTIMATED LOD: 4 :g per sample [2,3] PRECISION (þ r ):
0.04 [1]
APPLICABILITY: The working range is 17 to 560 ppm (50 to 1650 mg/m3 ) for a 3-L air sample. The method is applicable to 15-min samples. This method was developed to give improved sample stability compared to conventional charcoal tubes [3,4]. Side-by-side comparisons of this method and Method S3 were made in a sporting goods manufacturing plant in which MIBK, THF, and toluene were also present. This method has also been used successfully for methyl isobutyl ketone [1] and acetone [5].
INTERFERENCES: Under the given conditions, acetone and isopropanol have retention times similar to MEK. Mass spectrometry and other GC columns, e.g., SP-1000, or 30 m x 0.32-mm WCOT capillary coated with 1 :m DB-1, are aids to resolving interferences.
OTHER METHODS: This method is similar, except for the sampler, to Methods P&CAM 127 [6] and S3 [7,8], which it replaces.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYL ETHYL KETONE: METHOD 2500, Issue 2, dated 15 May 1996 - Page 2 of 4 REAGENTS:
EQUIPMENT:
1.
1.
2. 3. 4. 5.
Elu ent: Carbon disulfide *, chrom ato graphic quality, containing 0.1% (v/v) benzene* or other suitable internal standard. Methyl ethyl ketone Nitrogen or helium, purified. Hydrogen prepurified. Air, filtered.
2.
- See SPECIAL PRECAUTIONS
3. 4. 5.
Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID. Two sections of 20/40 mesh beaded carbon separated by 2-mm foam plug (front = ~15 0 m g, back = ~75 m g). Tub es are com m ercially available: Anasorb 747 (SKC 226-81), Anasorb CMS (SKC 226-121), Carboxen-564 (Supelco ORBO90), o r equ ivalent. Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. Gas chromatograph, FID, integrator and colum n (page 25 00-1). Vials, glass, 2-mL, PTFE -lined crimp caps. Syringe, 10-:L, readable to 0.1 :L.
SPECIAL PRECAUTIONS: Carbon disulfide is toxic and an acute fire and explosion hazard (flash point = !30 °C). W ork with it only in a hood. Benzene is a human carcinogen.
SAMPLING: 1. 2. 3. 4.
Calibrate each personal sampling pump with a representative sampler in line. Break the ends of the sampler imm ediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sam ple at an accurately known flow rate between 0.01 and 0.2 L/min for a total sample size of 0.25 to 12 L. Ca p the sam plers with plastic (not rub ber) cap s and pa ck sec urely for shipm ent.
SAMPLE PREPARATION:
5. 6. 7.
NO TE: Store s am ples in a freezer. Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool and foam plugs. Ad d 1.0 m L eluent to each vial. Attach crim p cap to each vial. Allow to stand 30 min with occasional agitation.
CALIBRATION AND QUALITY CONTRO L: 8.
9.
Calibrate daily with at least six working standards over the range 4 to 500 :g MEK per sample. a. Add known amounts of MEK to eluent in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samp les and blanks (steps 11 and 12). c. Prepare calibration graph (ratio of peak area of analyte to peak area of internal standard vs.
- g ME K).
Determine desorption efficiency (DE) at least once for each batch of sorbent used for sampling in the calibration range (step 8). Prepare three tubes at each of five levels plus three media blanks. a. Rem ove and disca rd back sorbent sec tion of a med ia blank sam pler. b. Inject a known amount of MEK directly onto front sorbent section with a microliter syringe. c. Ca p the tube. Allow to stand overnight.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYL ETHYL KETONE: METHOD 2500, Issue 2, dated 15 May 1996 - Page 3 of 4
10.
d. Deso rb (steps 5 through 7 ) and analyze together with working standards (steps 11 and 12). e. Prepare a gra ph o f DE vs. :g MEK recovered. Analyze three quality control blind spikes and three analyst spikes to insure that the calibration graph and D E graph are in control.
MEASUREMENT: 11.
12.
Set gas chro m atog raph acc ording to m anu facturer's rec om m end ations and to conditions given on page 25 00-1. Inject sam ple aliquot m anually using solvent flush techn ique or with autosam pler. NOTE: If pea k area is abo ve the linear ra nge of the working standard s, dilute with eluent, rean alyze and apply the appropriate dilution factor in calculations. Mea sure peak area. Divide the peak area of analyte by the peak area of internal standard on the same chromatogram.
CALCULATIONS: 13.
14.
Determine the m ass , :g (corrected for D E) of ME K found in the sam ple front (W f) and back (W b) sorbent sec tions, and in the average m edia blank front (B f) and back (B b) sorbent sections. NO TE: If W b > W f /10, report breakthrough and possible sample loss. Calculate conce ntration, C, of MEK in the air volume s am pled, V (L):
NO TE : :g/L = m g/m 3
EVALUATION OF METHOD: The method was evaluate d with spik ed sam plers and with atm ospheres generated by syringe pum p/a ir dilution, verified by infrared absorption. For Ambersorb XE-347 samplers, breakthrough (80% RH, 200 ppm, 0.3 L/min) = 16.4 L; DE (4 to 18 mg per sample) = 1.03; storage stability (0.7 to 4 mg per sample) = 90% after six wee ks at 25 °C; precision and a ccu racy as give n on pag e 25 00-1 (15 s am ples) [2]. A user ch eck g ave an estimated LOD of 4 :g M EK per s am ple [3]. Storage stability of MEK and m ethyl isobutyl ketone (M IBK) on An asorb CMS sam plers was determined for the Proficiency Analytic al Testing (PAT) program [1]. Stability of MEK (0.125, 0.622, and 2.282 mg per sample) was 94 to 99% after 90 days at -5 °C. Only the highest level (2.282 mg) was stable (96% rec overy) at ambient temperature for 30 days, and was stable for 180 days (98 % rec overy) at freezer tempe ratures (-5 °C). Results were similar for MIBK, although all concentration levels (0.103, 0.516, and 2.064 mg per sample) were stable for 30 days at ambient temperatures.
REFERENCES: [1] NIOSH [1996]. Six-month storage stability data for methyl ethyl ketone and methyl isobutyl ketone. Proficiency Analytical Testing program, Jensen Groff, unpublished data. [2] Slick , E. J. [19 83]. N IOS H, unpu blishe d da ta. [3] User c heck , UBT L, NIOS H Se q. #3990-J (un published, Augus t 29, 1983). [4] User c heck , DataChe m Labs., NIOS H Se q. #7053-L (un published, Augus t 9, 1990). [5] DataC hem Labs, NIO SH S eq. #7373-L (unpublished, Nov. 27, 199 1).
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYL ETHYL KETONE: METHOD 2500, Issue 2, dated 15 May 1996 - Page 4 of 4 [6] NIOSH [1977]. Organic solvents in air: Method P&CAM 127 . In: Eller PM, ed. NIOSH Manual of Ana lytical Methods, 2nd ed., V. 1, U.S. Department of Health, Education, and W elfare, Publ. (NIOSH) 77-157-A. [7] Ibid., V. 2, 2-Butanone: Method S3. U.S. Department of Health, Education, and W elfare, Publ. (NIOSH) 77-1 57-B . [8] NIOSH [1977]. Documentation of the NIOSH Validation Tests, S3, U.S. Department of Health, Education, and W elfare, Publ. (NIOSH) 77-185.
METHOD REVISED BY: Judd C. Posner, Ph.D., and Mary Ellen Cassinelli, NIOSH/DPSE.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition