Page:NIOSH Manual of Analytical Methods - 2558.pdf/2

 ACE TO IN: MET HO D 255 8, Issue 1, dated 15 M arch 200 3 - page 2 of 3 REAGENTS:

EQUIPMENT:

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

1. Sam pler: Anasorb CMS solid sorbent tube (SKC, Inc. # 226-121). 2. Personal sampling pump, 0.01 to 0.2 L/min, connected with flexible tubing. 3. Ga s ch rom atog raph equ ipped with F ID, da ta collection system, and capillary column with a dea ctivated glas s inlet liner(pag e 25 58-1 ). 4. Autosampler vials, 2-mL, glass, with PTFElined crimp caps. 5. Syringes, 10-µL, 25-µL, and 1-mL. 6. Pipettes, 3-mL and 5-m L. 7. Vo lum etric flas ks, 10-m L.

Ac etoin, c hrom atog raph ic grade.* Ac eton e, pesticide grad e.* Metha nol, pe sticide grad e.* Helium, pre-purified and filtered. Hydrogen, pre-purified and filtered. Air, compressed, purified, and filtered. Ca libration s tock solution: Ad d know n am oun ts of acetoin to solvent in 10-mL volumetric flask.
 * See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: Acetoin is a flamm able and toxic com pound. Ac etone and m ethanol are flamm able and pose a fire hazard. W ork with all chemicals in a well ventilated laboratory safety hood.

SAMPLING: 1. Ca librate each pers ona l sam pling pum p with a represe ntative sam pler in line. 2. Break the ends of the sampling tube imm ediately before sampling. Attach sampling tube to personal sampling pump with flexible tubing. 3. Sam ple at a n ac curately kn own flow ra te betwee n 0.01 an d 0.2 L/m in for a total sam ple size of 10 L. 4. Cap the samplers with plastic caps, pack in a manner to insure that the sam plers are kept in the dark, and are s hipped c old (5°C).

SAMPLE PREPARATION: 5. Place the front and back sorbent sections in separate amber vials. Place the glass wool plug preceding the front section into the vial containing the front sorbent section. Discard the urethane foam plugs. 6. Add 1.0 mL of the acetone/methanol (95:5) solvent into each vial. Securely attach crimp caps to each vial. 7. Plac e ea ch vial on a rotary m ixer fo r 1.5 hours.

CALIBRATION AND QUALITY CONTRO L: 8. Ca librate daily with at leas t six wo rking standa rds from below the LOD to 10 tim es the LO Q. If necess ary, additional standards may be added to extend the calibration curve. a. W eigh out a know n am ount of acetoin in a 10-m L volum etric flask a nd dilute to the m ark with solve nt. Prepare add itional standa rds by serial dilution in additional 10-m L volum etric flas ks. b. Analyze together with samp les and blanks (steps 11 and 12). c. Prepare c alibration graph (pe ak area vs µg ace toin). 9. Determine the desorption efficiency (DE) at least once for each lot of Anasorb CMS used for sampling in the c alibration rang es (s tep 8). a. Prepare three tubes at each of five levels plus three media blanks. b. Inject a known amount (5 to 20 µL) of DE stock solution directly onto the front section of each Anasorb CMS with a microliter syringe. c. Allow the tubes to air equilibrate for several minutes, then cap the ends of each tube and store overnight at ambient temperature. d. Deso rb (steps 5-7) and a nalyze together with standards and blanks (steps 11 and 12). e. Prepare a graph of DE vs µg acetoin recovered.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition