Methyl Acrylate (2552)
METHYL ACRYLATE MW: 86.1
C4 H6 O2 METHOD: 2552, Issue 1
2552
CAS: 96-33-3
RTECS: AT2800000
EVALUATION: PARTIAL
PROPERTIES:
OSHA : 10 ppm NIOSH: 10 ppm ACGIH: 2 ppm (skin notation) (1 ppm = 3.52 mg/m ) 3
Issue 1: 15 March 2003
flammable liquid; den = 0.9574 g/mL @ 20°C; BP = 80.5°C; VP = 65 mm Hg @ 20°C; Flash Point = -3°C; FP = -76.7°C; Vapor Density = 2.95.
SYNONYMS: Methoxycarbonylethylene, Methyl ester of acrylic acid, Methyl propenoate, 2-propenoic acid methyl ester.
SAMPLING SAMPLER:
SOLID SORBENT TUBE (Anasorb CMS, 150/75 mg)
FLOW RATE:
0.01 to 0.2 L/min
VOL-MIN: -MAX:
1 L @ 10 ppm 5L
SHIPMENT:
Keep cold; pack securely for shipment.
SAMPLE STABILITY:
30 days @ 5°C
BLANKS:
2 - 10 field blanks per set
ACCURACY RANGE STUDIED:
Not studied.
BIAS:
Not determined.
OVERALL PRECISION (Ö r T ):
Not determined.
ACCURACY:
Not determined.
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
methyl acrylate
DESORPTION:
1 mL of carbon disulfide with agitation.
INJECTION VOLUME:
1 µL
TEMPERATURE -INJECTION: 250 °C -DETECTOR: 300 °C -COLUMN: 35 °C (hold 3 min) to 150 °C (8°C/min) CARRIER GAS:
He (2.6 mL/min)
COLUMN:
Capillary, fused silica, 30-m x 0.53-mm ID; 3:m film crossbonded® 35% diphenyl-65% dimethyl polysiloxane or equivalent
CALIBRATION:
Solutions of methyl acrylate in CS2
RANGE:
1.9 to 172.3 µg per sample [1]
ESTIMATED LOD: 0.5 ug per sample [1] PRECISION ( þ r ):
0.007 [1]
APPLICABILITY: The working range is 0.11 to 9.79 ppm (0.39 to 34.5 mg/m3 ) for a 5 L air sample [1]. Method is applicable to any sampling environment where methyl acrylate is present in the vapor state.
INTERFERENCES: Any compound eluting during the analysis and having a similar retention time.
OTHER METHODS: This method udates NMAM 1459 [2] which is Method S38 from the 2nd edition of the NIOSH Manual of Analytical Methods [3]. Improvements include but are not limited to the following: smaller volume of desorption solvent required, desorption efficiency (DE) results were improved by using a different solid sorbent tube, and a lower LOD/LOQ was established [1]. A storage stability study was completed and was found acceptable with a 105.3% recovery after 4 weeks at 5°C [1].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ME TH YL AC RYLA TE: M ETH OD 2552, Issue 1, dated 1 5 Ma rch 2003 - page 2 of 3 REAGENTS:
EQUIPMENT:
1. 2. 3. 4. 5. 6.
1. Sampler: glass tube, 7 cm long x 6-mm ID, containing two sections of Anasorb CMS separated by a 3-mm section of polyurethane foam. Silanized glass wool plugs hold each section in place. Tubes are commercially available (SKC # 226 -121 or equivalent). 2. Personal sampling pump, 0.01 to 0.2 L/min, with flexible tubing. 3. Gas chromatograph, flame ionization detector (FID), integrator, and Rtx-35 fused silica capillary column. 4. Autosampler vials, glass, 12-mm crimp caps. 5. Syringes, 10-µL to 1-mL. 6. Volumetric flasks, 10-mL. 7. Pipets, various sizes.
Methyl acrylate, reagent grade (99 .9+).* Carbon disulfide, chromatographic grade*. Helium, purified. Hydrogen, purified. Air, prefiltered and purified. Calibration stock: Dilute 3 µL of Methyl acrylate in 10 m L solvent. Prepare remaining standards by serial dilution.
- See SPECIAL PRECAUTIONS
SPECIAL PRECAUTIONS: Carbon disulfide is toxic and flammable and should be handled in a well ventilated fume hood. Methyl acrylate reacts violently with strong oxidants resulting in an explosion and fire hazard. Methyl acrylate polymerizes easily under the effects of heat, light, and peroxides.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sample tube in line. 2. Break open the ends of the sample tube immediately prior to sampling. Attach sample tube to personal sampling pump with flexible tubing. 3. Sample at an accurately known flow rate between 0.01 and 0.2 L/min for a total sample size of 1 to 5 L. 4. Cap both ends of the sample tubes with plastic caps and pack cold for shipment.
SAMPLE PREPARATION: 5. Place the initial glass wool plug and front sorbent section of the sample tube into autosampler vial. Place the back sorbent section of the sample tube in separate autosampler vial. Discard the polyurethane foam separator and the remaining glass wool plug. 6. Add 1.0 m L of carbon disulfide to each vial and cap securely. 7. Let each vial stand for 30 minutes with occasional agitation. 8. Analyze each sample by GC.
CALIBRATION AND QUALITY CONTROL: 9. Calibrate daily with at least six working calibration standards from below the LOD to 10 times the LOQ. If necessary, additional standards may be added to extend the calibration curve. a. Add known amounts of calibration stock solution to carbon disulfide solvent in 10-m L volumetric flasks and dilute to the mark. b. Analyze together with samples and blank s (steps 11 and 12). c. Prepare calibration graph (peak area vs. µg methyl acrylate). 10. Determine the desorption efficiency (DE) at least once for each lot of Anasorb CMS used for sampling in the calibration range (ste p 9). a. Prepare three tubes at each of five levels plus three media blanks. b. Inject a known amount of calibration stock solution directly onto the front sorbent section of each Anasorb CMS tube.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYL ACRYLATE: METHOD 2552, Issue 1, dated 1 5 March 2003 - page 3 of 3 c. Allow the tubes to air equilibrate for several minutes, then cap the ends of the tubes and allow to stand overnight. d. Desorb (steps 5-8) and analyze together with standards and blanks (steps 11 and 12). e. Prepare a graph o f DE vs. µg methyl acrylate recovered.
MEASUREMENT: 11. Set gas chromatograph according to manufacturer’s recommendations and to conditions given on page 2552-1. Inject a 1-µL sample aliquot manually using the solvent flush technique or with an auto sampler. NOTE: If peak area is above the linear range of the working standards, dilute with carbon disulfide solvent, reanalyze and apply the appropriate dilution factor in the calculations. 12. Measure peak areas.
CALCULATIONS: 13. Determine the mass, µg (corrected for DE), for m ethyl acrylate found in the sample front (W f) and back (W b) sorbent sections, and in the average media blank front (B f) and back (B b) sorbent section s. NO TE: If W b > W f/10, report breakthrough and possible sample loss. 14. Calculate concentration, C, of methyl acrylate in the air volume sampled, V (L):
NO TE : :g/L = m g/m 3
EVALUATION OF METHOD: This method development was a result of requests to update and improve problematic gas chromatography methods. After determining that Anasorb CMS sorbent tubes resulted in improved DE recoveries when compared to the results previously obtained using coconut shell charcoal tubes [1], the desorption efficiency was determined for m ethyl acrylate at 5 levels ranging from 19.2 µg to 172.3 µg. The average DE for methyl acrylate was determined to be 92.3% using Anasorb CMS sorbent tubes [1] while the previously determined DE for methyl acrylate using charcoal tubes was 81 % [4]. The LO D was determined to be 0.5 µg per sample. The precision, as determined from the pooled relative standard deviation (S r), was determined to be 0.007. Methyl acrylate storage stability @ 0.5xR EL was acceptable after 30 days (105 .3% ) [1].
REFERENCES: [1] Pendergrass S M [1 999 ]. Backup Data Report for Methyl Acrylate Method Development, NIOS H/MR SB, Cincinnati, OH., (unpublished, January). [2] NIOSH [1984]. Methyl Acrylate: Method 1459 (supplement issued 8/15/94). In: Eller PM, ed. NIOSH Manual of Analytical Methods. 3 rd rev. ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (N IOS H) Publication N o. 84-100 . [3] NIO SH [1978]. Method S3 8 In: Taylor DG, e d. NIOS H Manual of Analytical Methods, 2 nd ed., Vol. 2. U.S. Department of Health, Education, and W elfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health. DHEW (NIOSH)Publ. No.77-157-B. [4] NIOSH [1977]. Docum entation of NIOSH Validation Tests, NIOSH Contract No. CDC-99-74-45.
METHOD WRITTEN BY:
Stephanie M. Pendergrass, NIOSH/DART
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition