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Method no.: |
PV2140 |
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Control no.: |
T-PV2140-01-0410-CH |
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Target Concentration:
OSHA PEL:
NIOSH REL
ACGIH TLV: |
2 ppm (5 mg/m3)
2 ppm (5 mg/m3) (Skin)
2 ppm (5 mg/m3) (4 ppm STEL) (Skin)
0.5 ppm (skin) |
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Procedure: |
Samples are collected by drawing a known
volume of air through glass sampling tubes containing coconut shell
charcoal. Samples are extracted with 95:5 methylene chloride:methanol and
analyzed by GC using a flame ionization detector (GC/FID). |
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Recommended sampling time and sampling rate: |
200 min at 0.05 L/min (10 L) |
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Reliable quantitation limit: |
0.07 mg/m3 |
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Special Requirement: |
Samples should be refrigerated upon receipt
at the laboratory. |
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Status of method: |
Partially validated method. This method has
been subjected to established evaluation procedures of the Methods
Development Team and is presented for information and trial use. |
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October 2004 |
Yogi Shah |
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Please note: For problems with accessibility in using
figures and illustrations in this method,
please contact the author at (801) 233-4900. |
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Chromatography Team
Industrial Hygiene Chemistry Division
OSHA Salt Lake Technical Center
Salt Lake City UT 84070-6406
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1. General Discussion
1.1 Background
1.1.1 History
This work was performed because the method that SLTC uses for allyl alcohol, NIOSH method 14021 ,does not have tests for the
effects of humid air on sampler capacity, or for sample storage stability.
Results presented in this method show that samples extracted with 1 mL of 95:5 methylene chloride:methanol solution had good extraction
efficiencies averaging 98.7%. The retention efficiency results showed no allyl alcohol on the back-up section of samples that had been
spiked with 100 µg of allyl alcohol and then had 10 L of humid air drawn through them. The storage stability results showed 89.1%
recovery for samples stored for up to 14 days at refrigerated temperature, and 83.9% at ambient temperature.
1.1.2 Toxic effects (This section is for information only and should not be taken as the basis of OSHA policy.)2
Allyl alcohol is not classified as carcinogen or a suspect carcinogen by ACGIH. It may cause lung damage, skin irritation and
irritation to eyes. The oral LD50 is 64 mg/kg for rats.
1.1.3 Workplace exposure3
Allyl alcohol is primarily used in manufacturing of allyl compounds, war gases, resins and plasticizers. No information on exposure is
available.
1.1.4 Physical properties and other descriptive information4,5
CAS number: |
107-18-6 |
IMIS6: |
0130 |
molecular weight: |
58.08 |
density: |
0.854 g/mL (25 °C) |
melting point: |
-50 °C |
boiling point: |
96-97 °C |
appearance: |
colorless liquid |
vapor pressure: |
2.67kPa @20 °C |
odor: |
mustard like |
molecular formula: |
C3H6O |
solubility: |
miscible with water, alcohol, chloroform |
synonyms: |
2- propen-1-ol, 1-propenol-3, vinyl
carbinol |
structural formula:
This method was evaluated according to the OSHA SLTC "Evaluation Guidelines for Air Sampling Methods Utilizing
Chromatographic Analysis"7. The Guidelines define analytical parameters, specify required laboratory tests, statistical calculations
and acceptance criteria. The analyte air concentrations throughout this method are based on the recommended sampling and analytical
parameters.
1.2 Detection limit of the overall procedure (DLOP) and reliable quantitation limit (RQL)
The DLOP is measured as mass per sample and expressed as equivalent air concentrations, based on the recommended sampling parameters.
Ten samplers were spiked with equal descending increments of analyte, such that the highest sampler loading was 2.5 µg of allyl alcohol.
This is the amount spiked on a sampler that would produce a peak at least 10 times the response for a sample blank. These spiked samplers
were analyzed with the recommended analytical parameters, and the data obtained used to calculate the required parameters (standard error
of estimate and slope) for the calculation of the DLOP. The slope was 1910 and the SEE was 138.4. The RQL is considered the lower limit
for precise quantitative measurements. It is determined from the regression line parameters obtained for the calculation of the DLOP,
providing 75% to 125% of the analyte is recovered. The DLOP and RQL were 0.22µg and 0.72µg, respectively. The recovery at the RQL was
89%.
Table 1.2
Detection Limit of the Overall Procedure
for Allyl alcohol
|
mass per sample
(µg) |
area counts
(µV-s) |
|
0 |
0 |
0.25 |
999 |
0.50 |
1258 |
0.75 |
1579 |
1.00 |
2138 |
1.25 |
2482 |
1.50 |
3034 |
1.75 |
3596 |
2.00 |
4052 |
2.25 |
4520 |
2.50 |
5027 |
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Figure 1.2.1 Plot of data to
determine the DLOP/RQL for allyl alcohol (y =1910x + 220) |
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Figure 1.2.2 is the chromatogram of the RQL level.
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Figure 1.2.2 Chromatogram of allyl alcohol at the RQL level. [key:(1) allyl alcohol] |
2. Sampling Procedure
All safety practices that apply to the work area being sampled should be followed. The sampling equipment should be attached to the
worker in such a manner that it will not interfere with work performance or safety.
2.1 Apparatus
2.1.1 Samples are collected using a personal sampling pump calibrated, with the sampling device attached, to within ± 5% of the
recommended flow rate.
2.1.2 Samples are collected with 7-cm × 4-mm i.d.× 7-mm o.d. glass sampling tubes packed with two sections (100/50 mg) of charcoal.
The sections are held in place with foam plugs with a glass wool plug at the front. For this evaluation, commercially prepared sampling
tubes were purchased from SKC, Inc. (catalog no. 226-01 lot 2000).
2.2 Reagents
None required
2.3 Technique
2.3.1 Immediately before sampling break off the ends of the flame-sealed tube to provide an opening approximately half the internal
diameter of the tube. Wear eye protection when breaking tube ends. Use tube holders to minimize the hazard of broken glass. All tubes
should be from the same lot.
2.3.2 The smaller section of the adsorbent tube is used as a back-up and is positioned nearest the sampling pump. Attach the tube
holder to the sampling pump so that the adsorbent tube is in an approximately vertical position with the inlet facing down during
sampling. Position the sampling pump, tube holder, and tubing so they do not impede work performance or safety.
2.3.3 Draw air to be sampled directly into the inlet of the tube holder. The air being sampled is not to be passed through any hose or
tubing before entering the sampling tube.
2.3.4 After sampling for the appropriate time, remove the adsorbent tube and seal it with plastic end caps. Seal each sample end-to-end
with an OSHA-21 form as soon as possible.
2.3.5 Submit at least one blank sample with each set of samples. Handle the blank sample in the same manner as the other samples
except draw no air through it.
2.3.6 Record sample air volumes (liters), sampling time (minutes), and sampling rate (L/min) for each sample, along with any potential
interferences on the OSHA-91A form.
2.3.7 Submit the samples to the laboratory for analysis as soon as possible after sampling. If delay is unavoidable, store the samples
at refrigerator temperature. Ship any bulk samples separate from the air samples.
2.4 Extraction efficiency
The extraction efficiency was determined by spiking charcoal tubes (SKC, lot 2000) with allyl alcohol at 0.1 to 2 times the target
concentration. These samples were stored overnight at ambient temperature and then extracted for 30 minutes with shaking, and analyzed.
The mean extraction efficiency over the studied range was 98.7%. The wet extraction efficiency was determined at 1 times the target
concentration by liquid spiking the analyte onto charcoal tubes which had 10 L humid air (absolute humidity of 15.9 mg/L of water, about
80% relative humidity at 22.2 °C) drawn through them. The mean recovery for the wet samples was 97.8%.
Table 2.4
Extraction Efficiency (%) of Allyl Alcohol
|
level
|
sampler number
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|
x target
concn |
Fg per
sample |
1 |
2 |
3 |
4 |
5 |
6 |
mean |
|
0.1 |
0.5 |
98.5 |
103.5 |
101.7 |
99.8 |
98.3 |
95.7 |
99.6 |
0.25 |
12.5 |
100.1 |
98.9 |
96.6 |
96.6 |
99.2 |
99.5 |
98.5 |
0.5 |
25 |
102.1 |
97.6 |
103.0 |
100.1 |
103.0 |
101.5 |
101.2 |
1.0 |
50 |
96.8 |
99.8 |
97.4 |
93.2 |
98.7 |
96.9 |
97.1 |
2.0 |
100 |
97.7 |
97.9 |
96.9 |
96.0 |
96.0 |
98.1 |
97.1 |
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|
1.0 (wet) |
50 |
97.8 |
98.8 |
97.3 |
96.8 |
97.6 |
98.2 |
97.8 |
|
2.5 Retention efficiency
Six charcoal tubes were spiked with 100µg of allyl alcohol, in the front section of the tubes, and allowed to equilibrate for 6 h. The
tubes had 10 L humid air (absolute humidity of 15.9 mg/L of water, about 80% relative humidity at 22.2 °C) pulled through them at 0.05
L/min. The samples were extracted and analyzed. The mean retention recovery was 97.4%. There was no analyte found on the back-up section
of any of the tubes.
Table 2.5
Retention Efficiency (%) of Allyl Alcohol |
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|
sample number
|
section |
1 |
2 |
3 |
4 |
5 |
6 |
mean |
|
front of spiked
tube |
96.1 |
95.5 |
97.5 |
97.9 |
100.9 |
95.9 |
97.4 |
rear of spiked
tube |
0.0 |
00.0 |
00. |
00.0 |
00.0 |
00.0 |
00.0 |
total |
96.1 |
95.5 |
97.5 |
97.9 |
100.9 |
95.9 |
97.4 |
|
2.6 Sample storage
Fifteen charcoal tubes were each spiked with 50µg of allyl alcohol. They were allowed to equilibrate for 6 h, then 10 L of air (absolute
humidity of 15.9 mg/L of water about 80% relative humidity at 22.2°C), were drawn through them. Three samples were analyzed immediately,
and the rest were sealed. Six were stored at room temperature (23 °C), while the other six were stored at refrigerated temperature
(4 °C). Three samples stored at room temperature and three samples stored at refrigerated temperature were analyzed after 7 days and the
remaining six after 14 days. The amounts recovered indicate acceptable storage stability for the time period studied. Refrigerated samples
show better recovery, therefore, it is advised to store samples at refrigerated temperature.
Table 2.6
Storage Test for Allyl Alcohol (% Recovery )
|
time (days) |
ambient
storage |
refrigerated
storage |
|
0 |
92.9 |
92.5 |
97.9 |
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|
7 |
85.7 |
87.2 |
87.0 |
88.1 |
90.2 |
88.2 |
14 |
81.0 |
83.9 |
86.7 |
90.1 |
88.9 |
88.3 |
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2.7 Recommended air volume and sampling rate
Based on the data collected in this evaluation, 10 L air samples should be collected at a sampling rate of 0.05 L/min for 200 minutes.
2.8 Interferences (sampling)
2.8.1 There are no known compounds which will severely interfere with the collection of allyl alcohol.
2.8.2 Suspected interferences should be reported to the laboratory with submitted samples.
3. Analytical Procedure
Adhere to the rules set down in your Chemical Hygiene Plan. Avoid skin contact and inhalation of all chemicals and review all appropriate
MSDSs.
3.1 Apparatus
3.1.1 A gas chromatograph equipped with an FID. An Agilent 6890 plus series Gas chromatograph equipped with a 7683 Automatic Sampler was
used in this evaluation.
3.1.2 A GC column capable of separating allyl alcohol from the extraction solvent, internal standard, and any potential interference. A
Phenomenex 60-m × 0.32-mm i.d. ZB-WAX (1.5-Fm df ) capillary column was used in this evaluation.
3.1.3 An electronic integrator or some other suitable means of measuring peak areas. A Waters Millennium32 Data System was used in this
evaluation.
3.1.4 Glass vials with poly (tetrafluoroethylene)-lined caps. Two-mL vials were used in this evaluation.
3.1.5 A dispenser capable of delivering 1.0 mL of extraction solvent to prepare standards and samples. If a dispenser is not available,
a 1.0-mL volumetric pipet may be used.
3.1.6 Volumetric flasks – 10-mL and other convenient sizes for preparing standards.
3.1.7 Calibrated 10-µL or 20-µL syringe for preparing standards.
3.1.8 A mechanical shaker. An Eberbach mechanical shaker was used in this evaluation.
3.2 Reagents
3.2.1 Allyl alcohol, reagent grade. Aldrich 99.5%, (lot 09427CS) was used in this evaluation.
3.2.2 Methanol, reagent grade. Fisher 99.8%, (lot 020390) was used in this evaluation.
3.2.3 Methylene chloride, HPLC grade. Fisher 99.7%, (lot 034459) was used in this evaluation.
3.2.4 2-Ethyl-1-hexanol, reagent grade, internal standard. Aldrich 99.7%, (lot 01319TR) was used in this evaluation.
3.2.5 The extraction solvent solution was methylene chloride:methanol (95:5) with 1.25µL/mL of 2-ethyl-1-hexanol as internal standard
3.3 Standard preparation
3.3.1 At least two separate stock standards should be prepared. Prepare a stock standard by injecting 3µL of allyl alcohol into a 10-mL
volumetric flask containing the extraction solvent. Dilute this stock standard 1:5 to prepare a working standard equivalent to the PEL.
3.3.2 Bracket sample concentrations with standard concentrations. If upon analysis, sample concentrations fall outside the range of
prepared standards, prepare and analyze additional standards to confirm instrument response, or dilute high samples with extraction solvent
and reanalyze the diluted samples.
3.4 Sample preparation
3.4.1 Remove the plastic end caps from the sample tubes and carefully transfer the adsorbent sections to separate 2-mL vials. Discard the
glass tube, urethane foam plug and glass wool plug.
3.4.2 Add 1.0 mL of extracting solvent to each vial.
3.4.3 Immediately seal the vials with poly(tetrafluoroethylene)-lined caps.
3.4.4 Shake the vials on a shaker for 30 minutes.
3.5 Analysis
3.5.1 Gas chromatographic conditions
GC conditions
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column: |
initial 70 °C, hold 4 min, program temperature at 10 °C/min to 220 °C, hold 2 min |
zone temperatures: |
250 °C (injector)
250 °C (detector) |
run time: |
21 min |
column gas flow: |
2.0 mL/min (hydrogen) |
injection size: |
1.0µL (10:1 split) |
column: |
Phenomenex -60-m × 0.32-mm i.d. capillary ZB-WAX with 1.5-FFm df |
retention times: |
5.6, 6.0 min solvent
9.4 min (allyl alcohol)
15.2 min (2-ethyl -1-hexanol) |
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FID conditions
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hydrogen flow: |
30 mL/min |
air flow: |
400 mL/min |
makeup flow: |
25 mL/min (nitrogen) |
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Figure 3.5.1 Chromatogram obtained at the target level
with the recommended conditions. [key: (1) impurity; (2) solvent (3) allyl
alcohol, and (4) 2-ethyl-1-hexanol] |
3.5.2 Peak areas are measured by an integrator or other suitable means.
3.5.3 An internal standard (ISTD) calibration method is used. A calibration curve can be constructed by plotting response of standard
injections versus micrograms of analyte per sample. Bracket the samples with freshly prepared analytical standards over the range of concentrations.
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Figure 3.5.3. Calibration curve
for allyl alcohol.
(y =1291x +1809) |
3.6 Interferences (analytical)
3.6.1 Any compound that produces a GC response and has a similar retention time as the analyte is a potential interference. If any
potential interference were reported, they should be considered before samples are extracted. Generally, chromatographic conditions can be
altered to separate an interference from the analyte.
3.6.2 When necessary, the identity or purity of an analyte peak can be confirmed by GC-mass spectrometry. Figure 3.6.2 is a mass spectrum
of allyl alcohol.
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Figure 3.6.2 Mass spectrum of
allyl alcohol |
3.7 Calculations
3.7.1 The amount of analyte per sampler is obtained from the appropriate calibration curve in terms of micrograms per sample, uncorrected for
extraction efficiency. This total amount is then corrected by subtracting the total amount (if any) found on the blank. The air
concentration is calculated using the following formulas.
|
where: |
CM is concentration by weight |
M is micrograms per sample |
V is liters of air sampled |
EE is extraction efficiency, in decimal form |
|
|
where: |
CV is concentration by volume (ppm) |
M
is 24.46 (molar volume at NTP) |
V is concentration by weight |
EE is molecular weight (58.08) |
|
4. Recommendations for Further Study
Collection, reproducibility, and other detection limit studies need to be performed to make this a fully validated method.
References
1. NIOSH Method 1402, .www.cdc.gov/niosh, (accessed October 2003).
2. 2004 TLV and BEIs, Threshold Limit Values for Chemical Substance and Physical Agents, American Conference of Governmental Industrial
Hygienists, (ACGIH): Cincinnati, OH, 2004.
3. O’Neil,M., The Merck Index, 13th ed., Merck & Co. Inc.: Whitehouse Station, NJ, 2001, p 297.
4. 2004 TLV and BEIs, Threshold Limit Values for Chemical Substance and Physical Agents, American Conference of Governmental Industrial
Hygienists, (ACGIH): Cincinnati, OH, 2004.
5. O’Neil,M., The Merck Index, 13th ed., Merck & Co. Inc.: Whitehouse Station, NJ, 2001, p 297.
6. OSHA Chemical Sampling Information, www.osha.gov, (accessed October 2003).
7. Burright, D.; Chan, Y.; Eide, M.; Elskamp, C.; Hendricks, W.; Rose, M. C. Evaluation Guidelines For Air Sampling Methods Utilizing
Chromatographic Analysis; OSHA Salt Lake Technical Center, U.S. Department of Labor, Salt Lake City, UT, 1999.
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