Acetoin (2558)
ACETOIN C4 H8 O2
MW: 88.11
METHOD: 2558, Issue 1
2558
CAS: 513-86-0
RTECS: EL8790000
EVALUATION: PARTIAL
PROPERTIES:
OSHA : None NIOSH: None ACGIH: None
Issue 1: 15 March 2003
liquid, solid (dimer); d= 0.9972 g/mL @ 20 °C; BP= 148 °C; FP = 50°C; MP= 15°C; Miscible in water and alcohol
SYNONYMS: 3-Hydroxy-2-butanone, 2,3-butanolone, acetyl methyl carbinol, dimethylketol
SAMPLING SAMPLER:
Anasorb CMS Solid Sorbent Tubes (150/75 mg)
FLOW RATE:
0.01 to 0.2 L/min
VOL-MIN: -MAX :
1L 10 L
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
Acetoin
DESORPTION:
1 mL of acetone/methanol (95:5) on rotary mixer for 1.5 hours
INJECTION VOLUME:
1µL
225°C 250°C 35°C (hold 3 min) to 200°C (6°C/min)
SAMPLE STABILITY:
30 days @ 5°C
TEMPERATURE -INJECTION: -DETECTOR: -COLUMN:
BLANKS:
10% of field samples
CARRIER GAS:
He (2.8 mL/min)
COLUMN:
Capillary, fused silica, 30 m x 0.32-mm ID; 1-µm film, Stabilwax-DA or equivalent
CALIBRATION:
Standard solutions in acetoin in acetone/methanol (95:5) solvent
RANGE:
3 to 378 µg
SHIPMENT:
Ship cold (5°C) and store in dark
ACCURACY RANGE STUDIED:
Not Determined
BIAS:
Not Determined
OVERALL PRECISION (Ö r T ): Not Determined ACCURACY:
Not Determined
ESTIMATED LOD: 1.0 µg PRECISION ( þ r ):
0.008
APPLICABILITY: The working range for acetoin was 0.6 to 75.6 mg/m3 for a 5 L air sample.
INTERFERENCES: Any compounds with similar retention times to acetoin.
OTHER METHODS: None determined.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition 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 ACE TO IN: MET HO D 255 8, Issue 1, dated 15 M arch 200 3 - page 3 of 3 10. Analyze a minimum of three quality control blind spikes and three analyst spikes to ensure that the calibra tion gra ph a nd D E graph are in c ontro l.
MEASUREMENT: 11. Set gas chromatograph according to manufacturer’s recomm endations and to the conditions listed on page 2558-1. Inject a 1-µL sample aliquot manually using the solvent flush technique or with an auto sam pler. Note: If peak a rea is above the linear range of the working standards, dilute with solvent, reanalyze and app ly the app ropriate dilution facto r in the c alculations. 12. Measure peak areas.
CALCULATIONS: 13. Determine the mass, µg (corrected for DE ), of acetoin found in the sam ple front (W f) and back (W b) sorbent sections, and in the average m edia blank front (B f) and back (B b) sorbent sections. Note: If W b > W f/10, report b reak throu gh a nd p oss ible sam ple loss. 14. Calculate conce ntration, C, of acetoin in the air volume sa m pled, V(L):
EVALUATION OF METHOD: This m etho d, like N MA M 2 557 (Diacetyl), was de velop ed in re spo nse to a request to identify and qua ntitate possible hazardous chemical causes of workplace lung disease occurring at a microwave popcorn packaging facility. Ac eto in, an inhalation irritan t and chem ically reactive compound, was identified as a possible suspect chem ical in the fa cility. Due to the reactivity of acetoin (under certain enviro nm ental conditions aceto in can be converted to diacetyl and vice ve rsa [2]), severa l spec ial handling re quirem ents were included in this m etho d de velop m ent. A deactivated glass inlet liner was used to retard the oxida tion of ace toin to diacetyl and to p reve nt analyte decomposition in the injection port. The Stabilwax-DA capillary was used to reduce peak tailing and decomposition of oxygenated compounds during analysis. The reactivity of acetoin was further retarded by using amber glassware and storage of stock and samples at 5°C. Application of these analytical conditions resulted in an average DE recovery of 94.9% over a range of 57 to 378 µg. T he re sults of the stora ge s tability study indicated that acetoin was stable for 7 days at 5°C with a recovery of 93.5%. A slow increase in the am oun t of diac etyl form ed d uring the study was n oted, with a m axim um of 16 -18% reco rded at 30 days. It should also be noted that the acetoin monom er (liquid) will convert to a dimer (white solid) upon standing. How ever, when dissolved, acetoin will convert back to the monom er in solution. Because of the limited solubility of acetoin some sonication may be required to fully dissolve the requ ired am oun ts in the solve nt.
REFERENCES: [1] Pende rgrass SM [2001]. Acetoin Back up Da ta Report, Oc tober. [2] Fix, G J[19 93]. D iacetyl: Form ation, R edu ction, and C ontro l, Brew ing T ech ., July/Augus t.
METHOD WRITTEN (REVISED) BY:
Stephanie M. Pendergrass, NIOSH/DART
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition