Page:NIOSH Manual of Analytical Methods - 2537.pdf/2

 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 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.
 * 1) 226-30-0 6 or equivalent).


 * 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