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1. General Discussion
||2 ppm (4.5 mg/m3) (OSHA
||Samples are collected on charcoal, desorbed with
acetone, and analyzed by gas chromatography using a
|Recommended air volume
and sampling rate:
|20 L at 0.2 L/min
|Detection limit of the
|0.01 ppm (0.026
|Reliable quantitation limit:
||0.3 ppm (0.66 mg/m3)
|Standard error of estimate
at the target
|Status of method:
||A sampling and analytical method which has been
subjected to the established evaluation procedures of the Organic
Methods Evaluation Branch
Methods Development Team
Industrial Hygiene Chemistry Division
OSHA Salt Lake Technical Center
Sandy UT 84070-6406
2. Sampling Procedure
1.2 Limit defining parameters (All of the acrylonitrile air
concentrations listed in this procedure are based on a 20-L air sample
and 1-mL desorption volume.)
A collection and analytical method was needed for acrylonitrile
which would be convenient, sensitive, and accurate. This evaluated
method, which is similar to a previously published method (Ref. 5.4) consists of collecting acrylonitrile vapor on charcoal,
desorbing with acetone containing an internal standard and analyzing
by gas chromatography (GC) equipped with a nitrogen/phosphorus
Two other methods also use charcoal for collection. One
recommended by NIOSH (Ref. 5.2) uses methanol for desorption and GC
with a flame ionization detector (FID) for analysis. However,
methanol does not provide adequate desorption efficiencies at low
loadings of acrylonitrile nor is the FID as sensitive or selective
for acrylonitrile as the NPD. The second method which uses GC/NPD
for analysis (Ref. 5.3), also uses methanol to desorb the charcoal
but with sonication to increase the desorption efficiency. Acetone
desorption requires no sonication.
Another sampling and analytical (GC) procedure reported in the
literature (Ref. 5.1) recommends collection on Porapak N adsorbent
and thermal desorption. Thermal desorption is inconvenient when the
identity of an analyte must be confirmed by an alternate analytical
1.1.2 Toxic effects (This section is for information only and
should not be taken as the basis of OSHA policy.)
Absorption of acrylonitrile may occur through unbroken skin and
from the respiratory and gastrointestinal tract. (Ref. 5.5)
Acrylonitrile exhibits the toxic characteristics of the cyanide ion,
and several researchers have attributed its toxicity to the cyanide
ion. But other researchers have concluded that acrylonitrile
toxicity is not due only to cyanide because of the ineffectiveness
of anti-cyanide drugs. (Ref. 5.5.)
Exposures at 636 ppm in air for 4 h were fatal to rats. Dogs
exposed to 50, 75, and 100 ppm levels for 7 h showed histologic
changes. (Ref. 5.5.)
An interim report from an oral toxicity study conducted by Dow
Chemical Company stated that rats of both sexes which ingested 35,
100 or 300 ppm in their drinking water developed tumors at all
acrylonitrile levels after 12 months. Another interim report from an
inhalation study on rats exposed to 0, 20, or 80 ppm, 6 h per day, 5
days per week, showed tumors at the 80 ppm level after 12 months and
on continued exposure, tumors were found in rats exposed at the 20
ppm level. (Ref. 5.6.)
Acrylonitrile poisoning in humans most frequently causes slight
jaundice, gastritis, respiratory difficulties, and fatigue. Workers
experienced respiratory and nervous system effects when exposed to
acrylonitrile at 35-220 mg/m3 levels for
20-45 min. (Ref. 5.6)
"Long-term exposure: Acrylonitrile has been shown to cause
cancer in laboratory animals and has been associated with higher
incidences of cancer in humans. Repeated or prolonged exposure of
the skin to acrylonitrile may produce irritation and dermatitis."
1.1.3 Potential workplace exposure
Acrylonitrile is used primarily in the manufacture of acrylic and
modacrylic fibers, acrylonitrile-butadiene-styrene and
styrene-acrylonitrile resins, and
butadiene-acrylonitrile copolymers (Ref. 5.6.). The
main uses of the resins,
styrene-acrylonitrile, are in automotive parts, pipe fittings,
drinking tumblers and other housewares items (Ref. 5.7.). Acrylic
and modacrylic fibers are used in clothing and home furnishings
(Ref. 5.6.). Acrylonitrile in conjunction with carbon tetrachloride
has been used as a fumigant for stored tobacco and for flour milling
In 1976 there were 690 million kilograms of acrylonitrile
produced in the United States. NIOSH estimates that there are
125,000 people potentially exposed in U.S. workplaces. (Ref. 5.6)
1.1.4 Physical properties (Ref. 5.7)
|boiling point range:
||77.5 - 79°C|
|flash point (open cup):
|vapor pressure (at 23°C):
||100 mm Hg|
||2-propenenitrile; cyanoethylene; vinyl cyanide;
fumigrain; ventox; carbacryl; acrylon; AN.|
1.2.1 Detection limit of the analytical procedure.
The detection limit of the analytical procedure is 0.36 ng per
injection. This is the amount of analyte which will give a peak
whose height is approximately 5 times the baseline noise. (Section
1.2.2 Detection limit of the overall procedure.
The detection limit of the overall procedure is 0.51 µg per
sample (0.026 mg/m3 or 0.01 ppm). This is
the amount of acrylonitrile spiked on a charcoal tube which allows
recovery of an amount equivalent to the detection limit of the
analytical procedure. (Section 4.1.2)
1.2.3 Reliable quantitation limit
The reliable quantitation limit is 13.2 µg per sample (0.66
mg/m3 or 0.3 ppm). This is the smallest
amount of acrylonitrile which can be quantitated within the
requirements of 75% recovery and 95% confidence limits of ±25%.
The reliable quantitation limit and detection limits reported in
the method are based upon optimization of the instrument for the
smallest possible amount of analyte. When the target concentration of
an analyte is exceptionally higher than these limits, they may not be
attainable at the routine operating parameters.
The sensitivity of the analytical procedure over a range
representing 0.5 to 2 times the target concentration is 1159 area
counts/(µg/mL). This is determined from the slope of the calibration
curve. (Section 4.4) The sensitivity will vary with the
The recovery of acrylonitrile from the charcoal tubes during
storage must be 75% or greater. The recovery from samples used in a
15-day storage test remained above 81% when the samples were stored
at ambient temperature. (Section 4.7)
1.2.6 Precision (analytical procedure only)
The pooled coefficient of variation obtained from replicate
determinations of analytical standards at 0.5, 1, and 2 times the
target concentration is 0.0051. (Section 4.3.1)
1.2.7 Precision (overall procedure)
The overall procedure must provide results at the target
concentration that are ±25% or better at the 95% confidence level.
The precision at the 95% confidence level for the
15-day storage test is ±12.6%. (Figure 4.7.2) This
includes an additional ±5% for sampling error.
Six charcoal tubes were spiked with known amounts of
acrylonitrile and analyzed immediately by a chemist unassociated
with this procedure. The average recovery was 98% with a standard
deviation of 3.4%. (Section 4.8)
1.3.1 Charcoal tubes are readily available.
1.3.2 The samples may be analyzed more than once if necessary.
1.3.3 The method is rapid and precise.
1.3.4 The NPD is selective and sensitive.
1.4.1 Acrylonitrile does not have constant desorption at
loadings below 40 µg for the 100-mg charcoal section and 16 µg for
the 50-mg section. This requires special consideration. (Section
1.4.2 The method has not been field tested.
3. Analytical Procedure
2.1.1 A personal sampling pump which may be calibrated within
±5% of the recommended flow rate should be used.
2.1.2 Coconut shell charcoal adsorbent tubes, 7-cm length, 6-mm
o.d. and 4-mm i.d. containing a 100-mg front section and a 50-mg
back section. For this evaluation, SKC lot 120 charcoal tubes were
2.3.1 Immediately before sampling, break open the ends of the
tubes. All tubes must be from the same lot of charcoal.
2.3.2 Connect the tube to the sampling pump with a short piece
of tubing. The 50-mg portion of the charcoal tube is used as a
backup section, therefore, air should pass through it after the air
has passed through the 100-mg section.
2.3.3 Position the tube vertically near the breathing zone of
2.3.4 Air being sampled must not pass through any hose or tubing
before entering the 100-mg section of charcoal.
2.3.5 Seal the ends of the tubes with plastic caps immediately
after sampling and then wrap with OSHA label 21.
2.3.6 Submit at least one blank charcoal tube with each set of
samples. Handle the blank tubes in the same manner as the samples
(break ends, seal, transport), but do not draw air through the
2.3.7 Transport the samples and corresponding paperwork to the
laboratory for analysis.
2.3.8 Submit bulk samples when necessary. Place bulk samples in
glass bottles with Teflon-lined caps and mail in packages which do
not contain air samples.
2.4.1 For this evaluation, duplicate breakthrough studies at
approximately 8 mg/m3 and 80% relative
humidity (RH) were performed using a sampling rate of 0.2 L/min. The
average air volume sampled before 5% breakthrough occurred was 36.7
L and the average loading on the 100-mg portion of charcoal was
0.295 mg. (Section 4.5.1)
2.5 Desorption efficiency
2.4.2 Several 5% breakthrough studies were also performed at the
ceiling concentration of 10 ppm (21.7
mg/m3) to determine the maximum sampling
flow rate that could be used to maximize the volume of air collected
in a 15-min sampling period. It was found that 5% breakthrough
occurred at an average of 35 min when a flow rate 0.5 L/min was
used. (Figure 4.5.2. Ceiling breakthrough studies performed April
2.5.1 The average desorption efficiency of acrylonitrile from
the 100-mg portion of charcoal liquid spiked at loadings above 40 µg
(0.5× target concentration) was 89%. At loadings lower than 40 µg,
the desorption efficiency becomes dependent on the loading of
acrylonitrile and additional calculations (Section 3.7.4.) must be
performed. (Section 4.6.1)
2.6 Recommended air volume and sampling rate
2.5.2 The desorption efficiency of the 50-mg portion of charcoal
was constant above a loading of 16 µg. This average desorption
efficiency was 89%. At loadings lower than 16 µg the desorption
efficiency is not constant and additional calculations (Section
3.7.4) must be performed. (Section 4.6.2)
2.6.1 The recommended air volume is 20 L taken at a flow rate
2.6.2 The recommended sampling conditions for monitoring ceiling
concentrations are a 15-min sample taken at a flow rate of 0.5
L/min. This provides a sample air volume of 7.5 L. (The ceiling PEL
for acrylonitrile is 10 ppm.)
2.7.1 Relative humidities greater than 80%, and temperatures
greater than 25°C, may cause a decrease in the capacity of the
charcoal to adsorb and retain acrylonitrile.
2.8 Safety precautions
2.7.2 It is not known if other chemicals may cause interferences
with the sampling procedure.
2.8.1 Wear eye protection when breaking off the ends of the
2.8.2 Position the sampling device on the worker so as not to
interfere with work or safety.
2.8.3 Observe all safety regulations of the area in which
sampling is performed.
4. Backup Data
3.1.1 Gas Chromatograph equipped with a nitrogen/phosphorus
detector: For this evaluation, a Hewlett Packard 5730A GC with a
Hewlett Packard NPD was used.
3.1.2 A GC column capable of separating acrylonitrile from the
solvent front, interferences listed, and the internal standard: For
this evaluation a 20-ft × 1/8-in. stainless steel column packed with
10% SP-1000 on 80/100 Supelcoport was used.
3.1.3 A method of peak area integration: A Hewlett Packard model
3354 data system was used in the evaluation.
3.1.4 Two-milliliter vials with Teflon-lined caps were used for
3.2.1 Acetone, reagent grade.
3.3 Standard preparation
3.2.3 Internal Standard: Any compound may be used provided it
does not adsorb onto charcoal from an acetone solution and it
responds with an NPD. For this evaluation, propionitrile, reagent
grade, was found suitable.
3.2.4 Hydrogen, GC grade
3.2.5 Air, GC grade.
3.2.6 Helium or nitrogen, GC grade.
3.2.7 Desorbing solution: Acetone containing 0.1 µL/mL
propionitrile was used in this evaluation.
Prepare standards with the desorbing solvent, either acetone alone
or acetone containing an internal standard. Standards should be
prepared in the range 0.1 µL/mL down to 0.01 µL/mL when sample air
volumes are 20 L. Sample concentrations should be bracketed with
3.4 Sample preparation
3.4.1 Place the 100-mg portion of charcoal in one vial and the
50-mg portion in a second vial. The glass wool and urethane plugs
3.4.2 Dispense 1.0 mL of the desorbing solvent into each vial
3.4.3 Immediately cap the vials and allow them to desorb for 1 h
with intermittent shaking.
3.5.1 GC conditions
Update, April 1983: If problems with tailing peaks and poor
separation of acrylonitrile and the internal standard occur with the
above conditions, an alternate column which may be used is a 4-ft ×
1/8-in. stainless steel column packed with Porapak QS. When this
column is used the oven temperature should be 140°C.
3.5.2 An internal standard method is preferable since it
corrects for injection size and slight changes in the NPD response.
3.5.3 A calibration curve is determined from the analytical
standards by plotting detector response against the analytical
standard concentrations (in µg/mL).
3.5.4 Samples are analyzed and the acrylonitrile peak areas are
3.6.1 Any compound which has the same general retention time as
acrylonitrile or the internal standard on the column chosen and
gives a NPD response is an interference.
3.6.2 Interferences can frequently be alleviated by changing the
GC conditions or column.
3.7.1 The concentration, in µg/mL, of each desorbed sample is
determined from the calibration curve (Section 3.5.3)
3.8 Safety precautions
3.7.2 The concentration for each sample is multiplied by the
desorption volume, 1 mL, to get the total mass of acrylonitrile
desorbed from the charcoal. This µg value is uncorrected for the
blank sample and desorption efficiency.
3.7.3 A blank correction is made to the results in Section 3.7.2, if necessary.
3.7.4 The blank corrected mass of acrylonitrile found in each
sample is corrected for incomplete desorption by use of the
appropriate option: (The desorption efficiencies (DE) used in this
method were obtained using SKC lot 120 charcoal and they should be
redetermined when different charcoal is used.)
When the mass of acrylonitrile found (Section 3.7.3) for the
100-mg portion of charcoal is 36 µg or more and for the 50-mg
portion of charcoal is 14 µg or more, the DE is constant (89%) and
the mass should be divided by 0.89 to make the DE correction.
When the mass of acrylonitrile found (Section 3.7.3) is less
than 36 µg for the 100-mg portion of charcoal or less than 14 µg for
the 50-mg portion, the desorption efficiencies decrease with
decreasing loadings (Table 4.6.1 and 4.6.2), and the correction
for incomplete desorption must be determined with the use of the
desorption curve prepared for each portion of charcoal. The
desorption curve for each portion of charcoal was prepared by
plotting analytical data obtained from spiked samples in the form of
"actual µg" versus "µg desorbed". (Figure 4.9.1 and Figure 4.9.2)
The equations of the curves (presented on the figures) may be used
to calculate the mass corrected for incomplete desorption.
Blank-corrected mass (100-mg portion) = 20 µg
3.7.5 The air concentration (in mg/m3)
of acrylonitrile is obtained by adding the mass from both portions
of charcoal together and dividing by the air volume in L. The
equivalent concentration in ppm at 760 mm Hg and 25°C may be
obtained by multiplying the mg/m3 air
concentration by the molar volume of an ideal gas, 24.46 L, and
dividing by the molecular weight, 53.1.
If the mass of acrylonitrile on either portion of charcoal is so
small as to have a corresponding desorption efficiency of less than
75%, these values cannot be defended by this evaluation.
||AX2 + BX|
|mass, corrected for DE = 25
3.7.6 When confirmation is required it should be obtained by
GC/mass spectrometry or another suitable technique. Retention time
on one column is not considered proof of identity.
3.8.1 Work in a hood when preparing standards and samples.
3.8.2 Keep volumetrics and vials containing solvents away from
sources of high temperature such as detectors and injectors.
3.8.3 Avoid skin contact with solvents.
3.8.4 Wear safety glasses at all times.
4.1 Detection limits
4.1.1 The detection limit of the analytical procedure was found
by injecting l µL of an analytical standard of 0.36 µg/mL (0.36
µg/mL × 0.001 mL = 0.36 ng/injection). This gave a peak which was
approximately 5 times the baseline noise. (Figure 4.1.1)
4.2 Reliable quantitation limit
4.1.2 The detection limit of the overall procedure is 0.51
µg/sample (0.026 mg/m3 or 0.01 ppm). This
is the amount of acrylonitrile which when spiked on a charcoal tube
will allow recovery of an amount equivalent to the detection limit
of the analytical procedure, 0.36 ng/injection. This value, 0.51
µg/sample, was obtained by plotting the µg of acrylonitrile spiked
onto charcoal tubes vs. the µg of acrylonitrile recovered. Then
using this curve to extrapolate from 0.36 µg recovered to the Y-axis
and the values of the µg spiked were read (Figure 4.1.2). The
injection size recommended in the analytical procedure (1 µL) was
used for the determination of this detection limit.
The reliable quantitation limit is that amount of acrylonitrile
which when spiked onto the sampling device will allow recovery of at
least 75% and have a precision (±1.96 SD) of ±25% or better. There are
two reliable quantitation limits for this method; one for the 100-mg
portion of a charcoal tube and another for the 50-mg portion. The
value for the 100-mg portion is 13.3 µg and for the 50-mg portion is
5.9 µg. (Figures 4.2.1 and 4.2.2, respectively). This is due to
differences in the desorption efficiencies of the different amounts of
charcoal. (Figures 4.6.1 and 4.6.2) The injection size recommended
in the analytical procedure (1 µL) was used for these determinations.
4.3 Precision data
4.3.1. The precision of the analytical procedure is defined as
the pooled coefficient of variation determined from replicate
injections of analytical standards at 0.5, 1, and 2 times the target
concentration. The pooled coefficient of variation is 0.0051. (Table
4.3.2. The precision of the overall procedure must be ±25% or
better at the 95% confidence level for samples collected at the
target concentration. The precision at the 95% confidence level for
the 15-day storage test is ±12.6%. (Table 4.7., Figure 4.7.2.) This
includes an additional ±5% for sampling error.
The sensitivity is defined to be the slope of the calibration
curve. (Table 4.4, Figure 4.4) The sensitivity is 1159 area counts
Sensitivity and Precision Data
|× target conc.
4.5.1 Five percent breakthrough is defined for this method as
the point during sampling of an atmosphere at twice the target
concentration, using only the 100-mg portion of a charcoal tube,
when the acrylonitrile concentration passing through the charcoal
tube is 5% of the concentration of the atmosphere being sampled. At
a flow rate of 0.2 L/min with RH of 80% the average air volume
sampled before 5% breakthrough occurred was 36.7 L and the average
capacity of the charcoal tubes was 0.295 mg. (Table 4.5.1, Figure
4.6 Desorption efficiencies
||air volume sampled
4.5.2 Breakthrough studies were performed in a similar manner at
the ceiling concentration PEL of 10 ppm. Five percent breakthrough
occurred at approximately 35 min using a flow rate of 0.5 L/min.
4.6.1. The DE for the 100-mg portion of charcoal was performed
by spiking the charcoal with microliter quantities of solutions
containing acrylonitrile in acetone. Six tubes were prepared at each
of several loadings, allowed to equilibrate overnight, then desorbed
with 1 mL of desorbing solution, and analyzed. The desorption
efficiencies at loadings equivalent to 0.5, 1, and 2 times the
target concentration were constant and averaged 89%. (Table 4.6.1.,
Figure 4.6.1.) The desorption efficiencies at lower loadings were
not constant. (Table 4.6.1., Figure 4.6.1.) Samples containing
loadings of acrylonitrile at these lower levels must have results
calculated according to Section 3.7.4.
Desorption Efficiencies From 100 mg Portions
|× target conc.
|% DE (µg
|× target conc.
|% DE (µg
|× target conc.
|% DE (µg
4.6.2 Desorption efficiencies were performed using the 50-mg
portion of charcoal. Again six tubes were spiked at each loading.
Three of the tubes for each loading were desorbed with 0.5 mL and
the other 3 with 1.0 mL to see if there was any relationship between
the ratio of solvent to charcoal. There was no apparent trend with
the amount of desorbing solvent added so all the data are presented
together in Table 4.6.2. There was a constant desorption efficiency
of 89% for loadings of acrylonitrile above 16 µg but at lower
loadings the desorption varied. (Table 4.6.2 and Figure 4.6.2)
Results for samples containing less than 16 µg on the 50-mg portion
of charcoal must be calculated as described in Section 3.7.4.
Desorption Efficiencies From 50 µg Portions
|× target conc.
|% DE (µg
|× target conc.
|% DE (µg
4.7 Storage data
Thirty-six charcoal tube samples were dynamically generated by
sampling an atmosphere at the target concentration with RH of 80%.
Twenty liters of air were drawn through each charcoal tube. Six of the
samples were analyzed immediately after collection. The remaining 30
samples were divided into two 15-sample sets. One set was stored in a
refrigerator (-5°C) and the other set was stored at room
temperature (approx. 21°C). On every third day, three samples from
each storage set were analyzed. The data are presented in Table 4.7
and in Figures 4.7.1 and 4.7.2.
Six charcoal tubes were spiked with acrylonitrile solutions. These
tubes plus a copy of this procedure were given to a chemist
unassociated with this method. The results are presented below.
Nine samples which had been stored for 29 days at -5°C showed loss
and migration of acrylonitrile with loss of precision. These data were
not used in this evaluation since the storage period exceeded 15 days.
Figure 4.1.1. Detection limit for analytical
Figure 4.1.2. Detection limit for the overall
Figure 4.2.1. Reliable quantitation limit (100 mg portion of
Figure 4.2.2. Reliable quantitation limit (50 mg portion of
Figure 4.4. Sensitivity.
Figure 4.5.1. Breakthrough.
Figure 4.5.2. Breakthrough at ceiling
Figure 4.6.1. Desorption efficiencies (100 mg portion of
Figure 4.6.2. Desorption efficiencies (50 mg portion of
Figure 4.7.1. Ambient storage of
Figure 4.7.2. Refrigerated storage of
Figure 4.8. Chromatogram of 0.1 µL/mL acrylonitrile
Figure 4.9.1. Curve to compute actual µg from 100 mg portion of
Figure 4.9.2. Curve to compute actual µg from 50 mg portion of
5.1 Campbell, D.N.; Moore, R.H.; Am. Ind. Hyg. Assoc. J.
1979, 40, pg. 904-9.
5.2 "NIOSH Manual of Sampling and Analytical Methods". D.G. Taylor
(Manual Coordinator). 2nd ed., U.S. DHEW/PHS/CDC/NIOSH, Vol. 3, method
5.3 Chambers, D.; Acrylonitrile (Organic Method Evaluation Branch,
OSHA Laboratory, Salt Lake City, Utah). unpublished 1978.
5.4 Marano, R.S.; Levine, S.P.; Harvey, T.M.; Anal. Chem.
1978, 50, pg. 1948-1950.
5.5 "Documentation of Threshold Limit Values"; 4th ed: American
Conference of Governmental Industrial Hygienists: Cincinnati, 1981.
5.6 "IARC Monograph on Some Monomers, Plastics and Synthetic
Elastomers and Acrolein"; International Agency for Research on Cancer:
Switzerland, 1979, vol. 19, pg. 73-85.
5.7 "General Industry: OSHA Safety and Health Standards (29 CFR
1910)"; U.S. Department of Labor: Washington D.C., 1981, Section
1910.1045, pg. 839.
The desorption efficiency of acrylonitrile with acetone was non-linear.
A study was performed to find a desorption solvent which could desorb at
least 75% of the acrylonitrile over the range of 0.1× to 2× the PEL,
using lot 2000 charcoal tubes from SKC. A mixed solvent of 95:5 methylene
chloride:methyl alcohol (with 1 µL/mL
n-hexyl alcohol internal standard) gave recoveries above 95% for
all concentrations spiked. The sensitivity of an analysis performed using
a capillary column is more than the sensitivity of an analysis using a
packed column, therefore, it was possible to perform this desorption study
using a flame ionization detector. For greater sensitivity, the
nitrogen/phosphorus detector, specified in this method, should be used.
The internal standard of n-hexyl alcohol cannot be used if the
analysis is performed using a nitrogen/phophorous detector.
||HP5890 gas chromatograph with flame ionization
||60-m × 0.32-mm i.d. capillary coated with a
5.0-µm df DB-1 (J&W Scientific, Folsom, CA)|
||1 µL (12:1 split)|
||50°C (column), hold 8 min, ramp at 10°C/min to
180°C, hold 6 min|
|column gas flow:
||2.8 mL/min (hydrogen)|
||1.9 mL/min (hydrogen)|
||5.089 min (methyl alcohol)|
10.036 min (acrylonitrile)
10.467 min (methylene chloride)
23.594 min (n-hexyl alcohol)
||hydrogen flow: 40 mL/min|
air flow: 450 mL/min
makeup flow: 30 mL/min (nitrogen)
Figure 1. A chromatogram of an analytical standard of 40 µg/mL
acrylonitrile in the solvent of 95:5 methylene chloride:methanol with 1
-hexanol internal standard. (1 = methanol; 2 = ethanol
contamination in the methanol; 3 = acrylonitrile; 4 = methylene chlorode;
and 5 = n
The desorption studies were performed by charcoal tubes, lot 2000, at
concentrations of 2.001, 4.002, 20.001, 40.02, and 80.04 µg
acrylonitrile, and allowing them to equilibrate overnight at room
temperature. They were opened, each section of the tube placed into a
separate labeled 2-mL vial, and desorbed with 1 mL of 95:5 methylene
chloride:methyl alcohol with 1.0 µL/mL
n-hexyl alcohol internal standard, and then placed on the shaker
for 1 hour. They were analyzed by gas chromatography with a flame
ionization detector (GC-FID). The detection limit was 1.0 µg.
|Desorption Efficiency of
Samples can be desorbed with a mixture of 95:5 methylene
chloride:methyl alcohol with 1.0 µL/mL
n-hexyl alcohol internal standard, and analyzed by GC-FID if the
recommended air volume of 20 liters is collected. When lower air volumes
are collected, the samples should be analyzed with a nitrogen/phosphorous
detector after desorbing with the 95:5 methylene:methanol without the n-hexyl
alcohol internal standard.