Methyl and Ethyl Methacrylate (2537)
METHYL AND ETHYL METHACRYLATE (1) H2 C=C(CH3 )COOCH3 (2) H2 C=C(CH3 )COOC2 H5 METHOD: 2537, Issue 3
MW: 100.12 CAS: 80-62-6 114.15 97-63-2
(1) 1 ppm = 4.10 mg/m (2) 1 ppm = 4.68 mg/m3 3
SYNONYMS:
Issue 1: 15 August 1990 Issue 3: 15 March 2003
PROPERTIES: (1) liquid; d = 0.944 g/mL @ 20°C; BP = 100°C; VP = 4.7 kPa (35 mm Hg) @ 20°C; explosive range 1.7 to 8.2% v/v in air. (2) liquid; d = 0.917 g/mL @ 20°C; BP = 119°C; flash point = 21.1°C; index of refraction = 1.4116 (25°C).
(1) Methyl ester of methacrylic acid, methyl-2-methyl-2-propenoate (2) Ethyl ester of methacrylic acid; ethyl-2-methyl-2-propenoate
SAMPLING SAMPLER:
SOLID SORBENT TUBE (XAD-2, 400/200 mg)
FLOW RATE:
0.01 to 0.05 L/min
VOL-MIN: -MAX:
1 L @ 100 ppm 8L
SHIPMENT:
In dry ice
SAMPLE STABILITY: BLANKS:
7 days @ 25°C; 31 days @ 5°C [1]
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
Methyl and ethyl methacrylate
DESORPTION:
2 mL CS2 with sonication for 30 minutes
INJECTION VOLUME:
1 µL
TEMPERATURE -INJECTION: 250°C -DETECTOR: 300°C -COLUMN: 50°C (3 min) to 150°C (8°C/min)
2 - 10 samples per set ACCURACY
CARRIER GAS:
Helium, 5.0 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 analytes in CS 2
RANGE:
(1) 0.9 to 8240 µg [1,2] (2) 1.5 to 275 µg [1]
RANGE STUDIED: (1) 193 to 725 mg/m3 (3-L samples) [3] (2) Not studied BIAS:
OVERALL PRECISION ( Ö r T ): ACCURACY:
RTECS: OZ5075000 OZ4550000
EVALUATION: (1) FULL (2) PARTIAL
OSHA : (1) 100 ppm; (2) None NIOSH: (1) 100 ppm; (2) None ACGIH: (1) 100 ppm; (2) None
2537
(1) 2.55% [3] (2) Not determined
(1) 0.063 [3] (2) Not determined (1) +/- 12.6% [3] (2) Not determined
ESTIMATED LOD: (1) 0.4 µg/sample (Instrumental)[1] (2) 0.5 µg/sample (Instrumental)[1] PRECISION ( þ r ):
(1) 0.009 (2) 0.025 [1]
APPLICABILITY: The working range for methyl methacrylate is 0.07 to 670 ppm (0.30 to 2747 mg/m3 ) and for ethyl methacrylate is 0.11 to 19.7 ppm (0.50 to 91.7 mg/m3 ) for a 3-L air sample.
INTERFERENCES: None identified. Chromatographic conditions may be modified to resolve any interferences.
OTHER METHODS: This method updates NMAM 2537, Issue 2 (4 th ed.) [4] which previously revised NIOSH method S43 [5]. Improvements include the evaluation and addition of ethyl methacrylate to the method, higher desorption efficiency (DE) recoveries at lower study levels for both analytes, lowered LOD values, the incorporation of capillary column chromatography for analyte resolution, and the completion of a 30 day storage stability study.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ME TH YL & ET HYL M ETH ACR YLAT E: ME TH OD 2537, Issue 3, dated 1 5 Ma rch 2003 - Page 2 of 4 REAGENTS:
EQUIPMENT:
1. M ethyl m etha crylate, A CS reag ent grade .* 2. Eth yl me thac rylate, AC S reage nt gra de.* 3. Carbon disulfide, low benzene grade.* 4. Helium, prepurified. 5. Hydrogen, prepurified. 6. Air, filtered, compressed.
1. Sam pler: glass tube, 7 cm long, 8-mm OD, 6mm ID, flame sealed ends with plastic caps, containing two sections (front = 400 mg, back = 200 m g) of XAD -2 resin (20/50 m esh), separated by silylated glass wool plugs (SKC
- 226-30-0 6 or equivalent).
2. Personal sampling pump, 0.01 to 0.05 L/min, with flex ible tubing attache d. 3. Gas chrom atograph, flam e ionization detector, suitable integrator system, and Rtx®-35 or equ ivalent fu sed silica ca pillary colum n. 4. Syringes, 10-µL, 25-µL, 250-µL, and 1-mL. 5. Flasks, 10-mL volumetric type. 6. Vials, 5-mL, glass with PTFE-lined screw caps, and 2-mL autosampler vials.
- See SPECIAL PRECAUTIONS
SPECIAL PRECAUTIONS: Carbon disulfide is toxic and a dangerous fire and explosion hazard (flash point = -30°C) so work in a hood is mandatory. Methyl and ethyl methacrylate are strong irritants and lachrymators.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampler imm ediately before sampling. Attach sampler to personal sampling pump with flexible tubing. 3. Sam ple at a known flow rate between 0.01 to 0.05 L/min for a sample size of 1 to 8 L. 4. Ca p the sam plers. Pac k secu rely in dry ice fo r shipm ent.
SAMPLE PREPARATION: 5. Plac e the front (along with first g lass woo l plug) and b ack sorb ent section s in se para te 5-m L vials. Discard remaining plugs. 6. Ad d 2.0 m L of carbon disulfide to each vial and cap securely. 7. Place each vial in a sonication bath for 30 minutes. 8. After sonication, transfer aliquots from each sample to 2 mL autosam pler vials and attach crimp caps.
CALIBRATION AND QUALITY CONTRO L: 9. Ca librate daily with at leas t six wo rking standa rds from below the LOD to 10 times the LO Q. If necessary additional standards may be added to extend the calibration curve. a. Add known amounts of calibration standards to carbon disulfide solvent in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samp les and blanks (steps 11an d 12). c. Prepare calibra tion gra ph (p eak area vs. µg an alyte). 10. Determine the desorption efficiency (DE) at least once for each lot of XAD-2 used for sampling in the calibra tion ran ge (s tep 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 XAD-2 tube.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ME TH YL & ET HYL M ETH ACR YLAT E: ME TH OD 2537, Issue 3, dated 1 5 Ma rch 2003 - Page 3 of 4 c. Allow the tub es to air equ ilibrate for several m inutes , then cap the ends of the tubes an d allow to stan d overnight. d. Deso rb (steps 5-8) and a nalyze together with standards and blanks (steps 11 and 12). e. Prepare a graph of DE vs. µg analyte recovered.
MEASUREMENT: 11. Set gas chromatograph according to manufacturer’s recomm endations and to conditions given on page 2537-1. Inject a 1-µL sample aliquot manually using the solvent flush technique or with an auto sam pler. NOTE: If peak area is above the linear range of the working standards, dilute with the carbon disulfide solvent, reanalyze and apply the appropriate dilution factor corrections in the calculations. 12. Measure peak areas.
CALCULATIONS: 13. Determ ine the ma ss, µg (correc ted for DE), for each analyte found in the sam ple front (W f) and back (W b) sorbent sections, and in the averag e m edia blank front (B f) and back (B b) sorben t sec tions. NOTE: If W b > W f/10, report breakthrough and possible sample loss. 14. Calculate conce ntration, C, of each analyte in the air volume sa m pled, V(L):
NO TE : :g/L=m g/m 3
EVALUATION OF METHOD: Initial Method Development Effort (Issues 1 and 2) Method S43 (methyl methacrylate) was issued on July 6, 1979, and validated over the range of 193 to 725 m g/m 3 [3]. Average DE recovery results achieved in two independent studies were 98.1% [3] and 96-100% [5] over the ra nge of 56 0 to 2350 µg/sample. Overall precision (S rT) was estimated to be 0.063. Breakthrough volume was 6.46 L at a g ene rated air conce ntration of 78 6 m g/m 3 for methyl methacrylate under conditions of 90% relative humidity [3]. Subsequent storage stability results indicated that methyl methacrylate was stab le for 32 da ys (97.3% ) and ethyl m etha crylate fo r 23 d ays (95-10 0% ) @ 4°C [5]. Current Method Development Effort (Issue 3) [1] The current m etho d de velop m ent effort w as the res ult of reque sts to evaluate and improve problematic gas chromatography m ethods as part of the NM AM m ethods upd ate project. Initial evaluations confirme d that XAD-2 (400/200 mg) sorbent tubes were still the most suitable media for the sam pling and a nalysis of bo th methyl and ethyl methacrylate. The average DE recoveries, using substantially lower analyte concentration ranges than in previous studies (10x LOQ to 0.1x REL vs. 0.5x REL to 2.0x REL), we re 100.4 % for m eth yl m etha crylate and 102 .3% for eth yl me thac rylate. The LOD values for both m ethyl and ethyl methac rylate were lowered by a factor of 20 to 0.4 and 0.5 µg/sample, respectively. A 31-day storage stability study was completed for bo th m ethyl m etha crylate (96 .2% @ 0.05x RE L/P EL ) an d ethyl methacrylate (99.8% @ 0.05x REL/PEL) at 5°C.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ME TH YL & ET HYL M ETH ACR YLAT E: ME TH OD 2537, Issue 3, dated 1 5 Ma rch 2003 - Page 4 of 4 REFERENCES: [1] Pe ndergrass S M [1999]. Meth od De velopm ent Effort Backu p D ata Re port fo r M eth yl and Ethyl Methac rylate, NIOS H, DP SE, AR DB, AC S, (unpublished). [2] Tanguay JF [1988]. Method Modification Effort for Methyl Methacrylate, NIOSH, DPSE, MRSB, (unpublished). [3] NIOSH [1979]. Backup Data Report for Methyl Methacrylate (S43), prepared under NIOSH C ontract 210-76-0123. [4] NIOSH [1994]. Methyl Methacrylate: Method 2537, Issue 2. In: Eller PM, Cassinelli ME, eds. NIOSH Ma nua l of Analytical Metho ds, 4 th ed. Cincinnati, OH: U.S. Dept. of Health and Human Services, Public Health Service, Center for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. [5] NIOSH [1980]. Methyl Methacrylate, Method S43. In:Taylor DG, ed. NIOSH M anual of Analytical Me thod s, 2 nd ed., Vol. 6. Cincinn ati, OH : U.S. Dept. of H ealth a nd H um an S ervices, P ublic H ealth Service, Center for Disease Control. DHHS (NIOSH) 80-125.
METHOD WRITTEN BY: ISSUE 1 and 2: Robert W . Kurimo, NIOSH/DPSE ; S43 originally validated under NIOSH Contract No. 210-76-0123.
ISSUE 3: Stephanie M. Pendergrass, NIOSH/DART
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition