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Phosphine
[283 KB PDF]
Related Information: Chemical Sampling -
Phosphine
|
| Method no.: |
1003 |
|
| Target concentration: |
0.3 ppm (0.42 mg/m3, 12.3 nmol/L) TWA |
|
| OSHA PEL: |
0.3 ppm (0.42 mg/m3 12.3 nmol/L) TWA |
|
| ACGIH TLV: |
0.3 ppm (0.42 mg/m3 12.3 nmol/L) TWA
1 ppm (1.4 mg/m3, 40.9 nmol/L) STEL |
|
| Procedure: |
Samples are collected by drawing workplace air, with personal sampling
pumps, through sampling cassettes containing a glass fiber filter and a mercuric chloride-treated polyester
filter. Samples are digested with sulfuric acid and analyzed by ICP-AES. |
|
| Recommended sampling time and sampling rate: |
240 min at 1.0 L/min (240 L) TWA
15 min at 2.0 L/min (30 L) STEL |
|
| Reliable quantitation limit: |
32 ppb (45 µg/m3) |
|
| Standard error of estimate at the target concentration: |
5.52% |
|
|
| Status of method: |
Evaluated method. This method has been subjected to the established
evaluation procedures of the Methods Development Team. This method supercedes Method ID-180. |
|
| Date: |
February 2000 |
|
| Chemist: |
Yihlin Chan
Phil Giles |
|
Methods Development Team
Industrial Hygiene Chemistry Division
OSHA Salt Lake Technical Center
Sandy UT 84070-6406
|
1. General Discussion
1.1 Background
1.1.1 History
With the application of phosphine in the manufacturing of semiconductors, the monitoring of workplace phosphine
becomes more important than before. Phosphine has been analyzed by directly injecting sampled air onto a GC
column. Both NPD1 and FPD2
have been used for detection. Wang et al. used gas sampling bags made of aluminum and polyester.3
The NIOSH method uses sampling tubes containing mercuric cyanide-coated silica gel. Samples are oxidized with
acidic permanganate and analyzed by colorimetry.4
OSHA Method ID-180 for sampling workplace phosphine
uses carbon bead coated with potassium hydroxide.5
The analysis is based on the oxidation of the collected phosphine with hydrogen peroxide, and the determination of
the resulting phosphite and phosphate by ion chromatography, but the method suffers from low recoveries.
Greenfield et al. determined phosphine by passing air through a solution of mercuric chloride. Hydrogen chloride
is liberated, causing a rise in conductance, proportional to the amount of phosphine absorbed.6
They proposed the following reaction between phosphine and mercuric chloride:7
PH3 + 3HgCl2
 P(HgCl) + 3HCl |
Matsumura and co-workers coated silica gel with mercuric chloride and used it to sample phosphine.8
Samples are oxidized with acidic permanganate and analyzed by colorimetry. The sampling capacity was 3 L with 0.3
ppm phosphine sampled at 0.3 L/min. The lower limit of quantitation was 0.054 ppm. The sampling time of 10 minutes
is not suitable for TWA sampling, and the colorimetric determinations are cumbersome.
ICP-AES has been applied in the analysis of phosphorus. Hamalova and co-workers determined the
phosphorus content of fertilizers using ICP-AES9.
Ardis and Baker monitored the fertilizer plant effluents for phosphorus using ICP-AES10.
Mortensen and co-workers collected phosphine in an impinger containing acidic permanganate solution and analyzed
by ICP-AES.11
In the present method a mercuric chloride-treated polyester filter is used to capture phosphine
and ICP-AES is used to analyze for the total phosphorus. A glass fiber filter is placed upstream to
remove any phosphorus-containing particulate and aerosol.
1.1.2 Toxic effects (This section is for information only and should not be taken as the basis of OSHA policy.)
Phosphine is toxic by inhalation, but its effects are not completely understood. The chief effects are central
nervous system depression and lung irritation. There may be pulmonarym edema, dilation of the heart, and hyperemia
of the visceral organs. Inhalation can cause coma and convulsions leading to death within 48 hours. However, most
cases recover without after-effects. Chronic poisoning, characterized by anemia, bronchitis, gastrointestinal
disturbances and visual, speech and motor disturbances, may result from continued exposure to very low
concentrations.12
1.1.3 Workplace exposure
Two main uses for phosphine are in the preparation of semiconductors and as a fumigant.13
Phosphine is commonly used in the electronics industry as an n-type dopant for silicon
semiconductors, and to a lesser extent for the preparation of gallium-indium-phosphide devices.
Phosphine generated in situ by the reaction of atmospheric moisture with pelletized calcium, aluminum, or
magnesium phosphide is used as a fumigant in, for example, grain silos. Other uses of phosphine are as:
polymerization initiator; condensation catalyst; chemical intermediate for phosphonium halides. Phosphine was not
listed in either 1982 or 1972 NIOSH National Occupational Exposure Survey.14
In the state of California for the period 1982-1992, there were reported 205 cases associated with
exposure to phosphine/phosphides.15
1.1.4 Physical properties and descriptive information16
| CAS number: |
7803-51-2 |
| synonyms: |
hydrogen phosphide; phosphorus trihydride |
| |
| molecular formula: |
PH3 |
| molecular weight: |
34.00 |
| boiling point: |
-87.7°C |
| melting point: |
-133.8°C |
| vapor pressure: |
3.14 × 104 mmHg at 20°C |
| odor: |
of decaying fish; of garlic |
| auto-ignition temperature: |
38°C (pure). Ignites readily at room temperature when other hydrides of phosphorus are present as
impurities. Combines violently with oxygen and the halogens. |
| solubility: |
soluble in ethyl alcohol and ether; slightly soluble in water (26mL in 100 mL at 17°C). |
| OSHA IMIS number: |
208017 |
This method was evaluated in part according to the OSHA SLTC "EVALUATION GUIDELINES FOR AIR SAMPLING METHODS
UTILIZING CHROMATOGRAPHIC ANALYSIS"18
and in part according to the Inorganic Method Development Guidelines19.
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. Air concentrations listed in ppm are referenced to 25°C and 101.3 kPa (760 mmHg).
1.2 Limit defining parameters
1.2.1 Detection limit of the analytical procedure
The detection limit of the analytical procedure is 0.088 µg/mL phosphorus. This is the concentration of
phosphorus that will give a detector response that is significantly different from the response of a reagent
blank. (Section 4.1)
1.2.2 Detection limit of the overall procedure
The detection limit of the overall procedure is 2.9 µg phosphorus per sample (10 ppb phosphine or 13 µg/m3).
This is the amount of phosphorus spiked on the sampler that will give detector response that is significantly
different from the response of a sampler blank. (Section 4.2)
1.2.3 Reliable quantitation limit
The reliable quantitation limit is 9.8 µg phosphorus per sample (32 ppb phosphine or 45 µg/m3).
This is the amount of phosphorus spiked on the sampler that will give detector response that is considered the
lower limit for precise quantitative measurements. (Section
4.2)
1.2.4 Instrument calibration
The standard error of estimate is 0.041 µg/mL phosphorus over the range of 1.0 to 8.0 µg/mL. This range
corresponds to 0.25 to 2 times the target concentration. (Section
4.3)
1.2.5 Precision
The precision of the overall procedure at the 95% confidence level for the ambient temperature 17-day
storage test (at the target concentration) from mercuric chloride-treated filters is ±10.8%. This
includes an additional 5% for sampling pump variability. (Section
4.4)
1.2.6 Recovery
The recovery of phosphine from samples used in a 17-day storage test remained above 94.8% when the samples were
stored at ambient temperature. (Section 4.5)
1.2.7 Reproducibility
Six samples collected from a controlled test atmosphere were submitted for analysis by the OSHA Salt Lake
Technical Center. The samples were analyzed according to a draft copy of this procedure after 38 days of storage
at ambient temperature. No individual sample result deviated from its theoretical value by more than the precision
reported in Section 1.2.5. (Section 4.6)
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 a manner that will not interfere with work performance or safety.
2.1 Apparatus
Samples are collected with 37-mm filter cassettes containing a glass fiber filter and a mercuric chloride-treated
filter.20
Samples are collected using a personal sampling pump calibrated, with the sampling device
attached, to within ±5% of the recommended flow rate.
2.2 Reagents
None required.
2.3 Technique
Remove the two end plugs from the cassette.
Attach the cassette to the sampling pump. Position the sampling pump, cassette and tubing so they do not impede
work performance or safety.
Draw the air to be sampled directly into the inlet of the cassette. For personal sampling, the air being sampled is
not to be passed through any hose or tubing before entering the sampling cassette.
After sampling for the appropriate time, remove the cassette and replace the two end plugs. Seal each sample end-to-end
with an OSHA-21 form.
Submit at least one blank sample with each set of samples. Handle the blank sampler in the same manner as the other
samples except draw no air through it.
Record sample air volume (liters), sampling time (minutes) and sampling rate (L/min) for each sample, along with
any potential interferences on the OSHA-91A form.
Submit the samples to the laboratory for analysis as soon as possible after sampling.
2.4 Sampler capacity (Section 4.7)
The sampling capacity was tested by sampling a dynamically generated test atmosphere of phosphine at 3.8 times the
target concentration (46.8 nmol/L, 1.59 mg/m3 or 1.34 ppm) at an absolute humidity of
16.3 milligrams of water per liter of air (74.9% relative humidity at 24°C). The samples were collected at 1.0
L/min. The 5% breakthrough sampling time was determined to be 335 min. The 5% breakthrough was not reached in 6
hours when tested at two times the target concentration. When tested at 113.4 nmol/L (2.8 times the ACGIH STEL) and
at a flow rate of 2.0 L/min, the 5% breakthrough sampling time was determined to be 40 min.
2.5 Recommended sampling time and sampling rate
Sample for up to 240 min at 1.0 L/min (240 L) to collect TWA (long-term) samples.
Sample for 15 min at 2.0 L/min (30 L) to collect short-term samples.
When short-term samples are collected, the air concentration equivalent to the reliable quantitation limit becomes
larger. For example, the reliable quantitation limit is 0.36 mg/m3 (10.5 nmol/L, 0.26
ppm) when 30 L are collected.
2.6 Interferences, sampling (Section 4.8)
The collection efficiency was above 94.6% when mercuric chloride-treated filters were used to sample a test
atmosphere containing the target concentration of phosphine and having an absolute humidity of 4.6 milligrams of
water per liter of air (22.2% relative humidity at 23.3°C).
The collection efficiency was above 75.0% when mercuric chloride-treated filters were used to sample a test
atmosphere containing 0.08 times the target concentration of phosphine and having an absolute humidity of 15.6
milligrams of water per liter of air (64.1% relative humidity at 26.0°C).
The collection efficiency was above 99.6% when the samplers, whose front glass fiber filter had been spiked with
2.4 mg of ammonium phosphate dibasic,21
were used to sample a test atmosphere containing one times the target concentration of phosphine and having an
absolute humidity of 15.5 milligrams of water per liter of air (70.9% relative humidity at 24.1°C). The average
collection efficiency was 101.1% for the control samples.
The collection efficiency was above 96.7% when the samplers, whose front glass fiber filter had been spiked with
0.214 mg of DDVP,21 were used to sample a test atmosphere containing one times the target
concentration of phosphine and having an absolute humidity of 15.5 milligrams of water per liter of air (70.9%
relative humidity at 24.1°C). The average collection efficiency was 101.1% for the control samples.
3. Analytical Procedure
Adhere to the rules set down in your Chemical Hygiene Plan22.
Avoid skin contact and inhalation of all chemicals. Review appropriate MSDSs before beginning work.
3.1 Equipment
3.1.1 Inductively coupled plasma-atomic emission spectrometer (ICP-AES). A Perkin-Elmer Optima 3000 DV, with
its accessories including auto-sampler, peristaltic pumps, and mass flow controller, was used in this evaluation.
The software controls the instrument and provides the analytical results.
3.1.2 Borosilicate glass Phillips beakers, 125-mL.
3.1.3 Borosilicate glass volumetric flasks, 25-mL.
3.1.4 Hot plate.
3.2 Reagents
3.2.1 Sulfuric acid, reagent grade. Sulfuric acid, 96.5%, purchased from JT Baker was used (Lot 15055).
3.2.2 Hydrogen peroxide, 30%. Hydrogen peroxide, 30%, was purchased from Mallinckrodt.
3.2.3 deionized water.
3.2.4 Phosphorus standard, 1000 µg/mL. Single element phosphorus standard, 1000 µg/mL, was purchased from SPEX
Industries (Edison, NJ) and from CPI International (Santa Rosa, CA).
3.2.5. Nitric acid.
3.3 Standard preparation
3.3.1 Working standard, 10 µg/mL phosphorus (10 ppm P). Pipet 1.00 mL of 1000 µg/mL phosphorus stock solution
into a 100-mL volumetric flask. Add about 50 mL of deionized water. Add 8 mL of concentrated sulfuric
acid. Allow the solution to cool. Add deionized water to the mark.
3.3.2 Prepare a reagent blank in a 100-mL volumetric flask by adding 8 mL of sulfuric acid to about 50 mL of
deionized water, allowing it to cool, and adding deionized water to the mark.
3.4 Sample preparation
Caution: Mercuric chloride is a "violent poison" and "slightly volatile at ordinary
temperature"23. It has a
vapor pressure of 13 Pa (0.1 torr) at 100°C.24
Handle samples in a hood.
Clean the insides of the 125-mL Phillips beakers by refluxing 1:1 nitric acid using a hot plate in a ventilated
hood. Carefully pour the used 1:1 nitric acid into an appropriate labeled container. Allow the beakers to cool,
then rinse several times with deionized water. Using a forceps, place sample filters in separate labeled and washed
Phillips beakers. Discard the glass fiber filter.
Add 2 mL of concentrated sulfuric acid to each beaker.
Heat the beakers on a hot plate for approximately 10 minutes. The solutions should become dark and then light
brown.
Add a few drops of 30% hydrogen peroxide until each solution becomes colorless. Remove the beakers from the hot
plate and allow to cool.
Quantitatively transfer the solutions into 25-mL volumetric flasks using deionized water. Add deionized water to
the mark.
3.5 Analysis
|
Follow the standard operating procedure for ICP-AES. There are four available wavelengths for phosphorus
determination: 178.221, 177.433, 213.616, and 214.918 nm. The wavelength of 178.221 nm was used in this
evaluation. The results from the other three wavelengths are useful for confirmation. Calibrate with the 10
µg/mL phosphorus standard and the reagent blank. The instrument software allows for taking a specified number
of readings and calculating the averages. |
Figure 3.5 Calibration curve of phosphorus. (Y = 268.9X + 31.95) |
ICP operating parameters:
| number of replicates: |
2 |
| integration times: |
minimum: 5.00 sec
maximum: 20.00 sec |
| plasma flow: |
15 L/min |
| auxiliary plasma flow: |
0.5 L/min |
| nebulizer gas flow: |
0.60 L/min |
| power: |
1450 watts |
| viewing height: |
15 mm |
| plasma view: |
radial |
For the calibration curve presented in Figure 3.5, three readings were taken and the individual data points were
plotted.
3.6 Interferences (analytical)
Copper and iron, when present in large amounts, may interfere with phosphorus detection at 213.616 and 214.914 nm.
The ICP software allows for the correction of spectral interferences. Consult the instrument manual for inter-element
corrections.
3.7 Calculations
The concentration of phosphorus for the sample is obtained from the appropriate calibration curve in terms of
micrograms phosphorus per milliliter. This concentration is then corrected by subtracting the concentration of the
blank. The air concentration is calculated using the following formulas.
| CM = |
(Cp)(Vd)(34.00)
(V)(30.97) |
|
| where: |
CM |
is concentration by weight (mg/m3) |
| Cp |
is micrograms phosphorus per milliliter |
| V |
is liters of air sampled |
| Vd |
is the final volume (mL) to which the sample is diluted |
| 34.00 |
is the molecular weight of phosphine (g/mol) |
| 30.97 |
is the atomic weight of phosphorus (g/mol) |
|
| |
|
|
| where: |
CV |
is concentration by volume (ppm) |
| 24.46 |
is molar volume at 25°C (L/mol) |
| CM |
is concentration by weight (mg/m3) |
| 34.00 |
is the molecular weight of phosphine (g/mol) |
|
4. Backup Data
General background information about the determination of detection limits and precision of the overall procedure is
found in the "Evaluation Guidelines for Air Sampling Methods Utilizing Chromatographic Analysis"25.
The Guidelines define analytical parameters, specific laboratory tests, statistical calculations and acceptance
criteria.
4.1 Detection limit of the analytical procedure (DLAP)
A 10 µg/mL phosphorus standard and a reagent blank were analyzed ten times and the data obtained were used to
determine the DLAP according to the following formula.26
At 178.221 nm, ] the 10 µg/mL standard gave an average intensity of 2717.8. The reagent blank gave an average
intensity of 25.8 and a standard deviation of 7.87. DLAP was calculated to be 0.088 µg/mL phosphorus.
| where: |
DL |
is detection limit |
| k |
is a constant, equals 3 |
| Sdblk |
is the standard deviation of the reagent blank |
| Cstd |
is the concentration of the standard |
| Istd |
is the intensity of the standard |
| Iblk |
is the intensity of the blank |
| DL = |
k(Sdblk)(Cstd)
(Istd - Iblk) |
4.2 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 phosphorus, such that the highest
sampler loading was 20 µg/sample. This is the amount spiked on a sampler that would produce a peak approximately
10 times the response of a sample blank. These spiked samplers and the sample blank were analyzed with the
recommended analytical parameters, and the data obtained used to calculate the required parameters (standard error
of estimate and the slope) for the calculation of the DLOP. Values of 10.55 and 10.34 were obtained for the slope
and standard error of estimate respectively. The DLOP was calculated to be 2.94 µg phosphorus per sample (9.67 ppb
phosphine, 13.4 µg/m3).
Table 4.2
Detection Limit of the overall procedure
|
Mass per sample
µg phosphorus |
Intensity at
178.221 nm |
|
| 0 |
34.1 |
| 2 |
69.8 |
| 4 |
102.3 |
| 6 |
109.5 |
| 8 |
111.5 |
| 10 |
144.1 |
| 12 |
167.8 |
| 14 |
187.2 |
| 16 |
209.3 |
| 18 |
248.1 |
| 20 |
249.3 |
|
|
|
Figure 4.2 Plot of data to determine the DLOP/rql.(Y = 10.55X + 42.91) |
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 RQL is 9.80 µg phosphorus per sample (1.32 nmol/L, 32.2 ppb phosphine, 44.8 µg/m3)
Recovery at this concentration is 95.9%.
4.3 Instrument calibration
The standard error of estimate was determined from the linear regression of data points from standards over a range
that covers 0.25 to 2 times the target concentration. A calibration curve was constructed and shown in
Section 3.5 from the three readings of five standards. A standard error of estimate of 15.38 and a slope of 268.7
mL/µg were obtained for the curve. The standard error of estimate of the calibration is calculated to be 0.0572
µg/mL phosphorus.
Table 4.3.
Instrument Calibration
|
standard concn
(µg/mL P) |
net intensity
at 178.221 nm |
average |
|
| 1.00 |
303.5 |
305.4 |
298.4 |
302.4 |
| 2.00 |
570.6 |
567.9 |
568.7 |
569.0 |
| 4.00 |
1086.5 |
1104.3 |
1117.3 |
1102.7 |
| 6.00 |
1663.5 |
1646.6 |
1647.0 |
1652.4 |
| 8.00 |
2152.3 |
2173.6 |
2216.5 |
2180.8 |
|
4.4 Precision (overall procedure)
The precision at the 95% confidence level is obtained by multiplying the standard error of estimate by 1.96 (the z-statistic
from the standard normal distribution at the 95% confidence level). In Section 4.5, 95% confidence intervals are
drawn about their respective regression lines in the storage graph figures. The precision of the overall procedure
of ±10.8% was obtained from the standard error of estimate of 5.52% in
Figure 4.5.1.
4.5 Storage test
Storage samples for phosphine were prepared by collecting samples from a controlled test atmosphere using the
recommended sampling conditions. The concentration of phosphine was at the target concentration with an absolute
humidity of 14.8 milligrams of water per liter of air (86.3% at 19.9&176;C).27
Thirty-three storage samples were prepared. Three samples were analyzed on the day of generation. Fifteen of the
samples were stored at reduced temperature (4°C) and the other fifteen were stored in a closed drawer at ambient
temperature (about 22°C). At 3-4 day intervals three samples were selected from each of the two sets
and analyzed.
Table 4.5
Storage Test for Phosphine
|
| time (days) |
ambient storage recovery (%) |
|
refrigerated storage recovery (%) |
|
| 0 |
96.7 |
93.7 |
94.3 |
|
96.7 |
93.7 |
94.3 |
| 4 |
96.1 |
95.0 |
96.7 |
|
98.9 |
93.3 |
91.1 |
| 7 |
90.8 |
94.9 |
93.7 |
|
92.4 |
93.7 |
96.2 |
| 10 |
92.2 |
97.3 |
99.9 |
|
95.6 |
97.8 |
95.9 |
| 14 |
95.9 |
98.5 |
95.4 |
|
99.7 |
101.3 |
98.4 |
| 17 |
97.1 |
96.7 |
92.3 |
|
94.8 |
94.0 |
95.4 |
|
|
|
| |
Figure 4.5.1 Ambient storage tests for phosphine |
|
Figure 4.5.2 Refrigerated storage tests for phosphine |
4.6 Reproducibility
Six samples were collected from a controlled test atmosphere similar to that which was used in the collection of
the storage samples. The samples were submitted to the OSHA Salt Lake Technical Center for analysis. The samples
were analyzed after being stored for 38 days at ambient temperature. No sample result for phosphine had a deviation
greater than the precision of the overall procedure determined in
Section 4.4.
Table 4.6
Reproducibility Data for Phosphine on Mercuric Chloride-Treated Filter
|
theoretical
concentration
(µg/L) |
recovered
amount
(µg/mL P) |
air volume
(L) |
concentration
(µg/L) |
recovery
(%) |
deviation
(%) |
|
| 0.4055 |
3.350 |
245.0 |
0.3753 |
92.6 |
-7.4 |
| 0.4055 |
3.339 |
242.9 |
0.3773 |
93.0 |
-7.0 |
| 0.4055 |
3.331 |
242.3 |
0.3773 |
93.0 |
-7.0 |
| 0.4055 |
3.247 |
241.7 |
0.3687 |
90.9 |
-9.1 |
| 0.4055 |
3.452 |
242.0 |
0.3915 |
96.5 |
-3.5 |
| 0.4055 |
3.403 |
245.0 |
0.3812 |
94.0 |
-6.0 |
|
4.7 Sampler capacity
The sampling capacity of the mercuric chloride-treated filter was tested by sampling from a dynamically generated
test atmosphere of phosphine (46.8 nmol/L or 1.34 ppm at Salt Lake City) with an absolute humidity of 16.3
milligrams of water per liter of air (74.9% relative humidity at 24°C) using two samplers connected in series.
Three sets of samples were collected at 1.0 L/min. At 30-minutes intervals the downstream sampler was
replaced with a fresh one. The 5% breakthrough was seen at 335 L of sampled air. No breakthrough was seen in 6
hours when the test was conducted at 26.2 nmol/L (0.738 ppm at Salt Lake City). The recommended sampling time is 4
h.
When tested at 113.4 nmol/L (2.8 times the ACGIH STEL TLV) and at a flow rate of 2.0 L/min, the 5% breakthrough
time was found to be 40 min. The recommended short term sampling time and flow rate are 15 min and 2.0 L/min.
Table 4.7.1
Breakthrough of Phosphine with Mercuric Chloride-Treated Filter at 46.8 nmol/L and at 1 L/min
|
test
no. |
sampling time
(min) |
air vol
(L) |
downstream concn
(nmol/L) |
breakthrough
(%) |
|
| 1 |
0-130 |
65.6 |
0.80 |
1.7 |
| |
130-206 |
169.5 |
0.61 |
1.3 |
| |
206-240 |
225.0 |
0.05 |
0.1 |
| |
240-270 |
257.3 |
0.01 |
0.0 |
| |
270-302 |
288.6 |
0.15 |
0.3 |
| |
302-330 |
318.8 |
1.89 |
4.0 |
| |
330-360 |
348.1 |
4.27 |
9.1 |
| |
| 2 |
0-130 |
65.0 |
0.74 |
1.6 |
| |
130-206 |
168.0 |
Outlier |
- |
| |
206-240 |
223.0 |
1.39 |
3.0 |
| |
240-270 |
255.0 |
0.61 |
1.3 |
| |
270-302 |
286.0 |
1.62 |
3.4 |
| |
302-330 |
316.0 |
1.35 |
2.9 |
| |
330-360 |
345.0 |
2.97 |
6.3 |
| |
| 3 |
0-130 |
64.6 |
0.54 |
1.1 |
| |
130-206 |
166.9 |
0.50 |
1.1 |
| |
206-240 |
221.5 |
1.46 |
3.1 |
| |
240-270 |
253.3 |
0.62 |
1.3 |
| |
270-302 |
284.1 |
0.62 |
1.3 |
| |
302-330 |
313.9 |
1.50 |
3.2 |
| |
330-360 |
342.7 |
1.85 |
4.0 |
|
Figure 4.7.1 five percent breakthrough air volume for phosphine at 46.8 nmol/L (3.8 times the target concentration) and a flow rate of 1.0 L/min. |
Table 4.7.2
Breakthrough of Phosphine with Mercuric Chloride-Treated Filters at 2 L/min and at 113.4 nmol/L
(3.857 mg/m3)
|
test
no. |
sampling time
(min) |
air vol
(L) |
downstream concn
(nmol/L) |
breakthrough
(%) |
|
| 1 |
0 - 33 |
32.8 |
4.1 |
3.6 |
| |
33 - 69 |
101.3 |
14.3 |
12.6 |
| |
69 - 99 |
166.8 |
22.1 |
19.5 |
| |
99 -133 |
230.4 |
27.6 |
24.3 |
| |
| 2 |
0 - 33 |
33.0 |
0.3 |
0.2 |
| |
33 - 69 |
102.0 |
0.1 |
0.1 |
| |
69 - 99 |
168.0 |
12.8 |
11.3 |
| |
99 - 133 |
232.0 |
34.3 |
30.3 |
| |
| 3 |
0 - 33 |
33.1 |
1.4 |
1.3 |
|
33 - 69 |
102.2 |
3.3 |
2.9 |
| |
69 - 99 |
168.3 |
19.0 |
16.8 |
| |
99 -133 |
232.5 |
36.6 |
32.3 |
|
Figure 4.7.2 five percent breakthrough air volume for phosphine at 113.4 nmol/L (2.8 times ACGIH STEL TLV) and a flow rate of 2.0 L/min. |
4.8 Interferences (sampling)
Low humidity
The ability of the mercuric chloride-treated filter to collect phosphine from a relatively dry atmosphere was
tested by sampling an atmosphere containing 12.2 nmol/L (one times the target concentration) of phosphine at an
absolute humidity of 4.6 milligrams of water per liter of air (22.2% relative humidity at 23.3°C). Six samples
were collected from the test atmosphere at 1.0 L/min for 240 minutes. All of the samples were immediately analyzed.
The samples had collected 94.6%, 94.9%, 96.8%, 98.5%, 95.0%, and 103.3% of theoretical.
Low concentration
The ability of the mercuric chloride-treated filter to collect phosphine at low concentrations was tested by
sampling an atmosphere containing 1.31 nmol/L (0.11 1 times the target concentration) of phosphine at an absolute
humidity of 14.0 milligrams of water per liter of air (63.8% relative humidity at 24.2°C). Six samples were
collected from the test atmosphere at 1.0 L/min for 240 min. The samples were immediately analyzed. The samples had
collected 87.2%, 88.8%, 81.2%, 84.4%, 83.8%, and 82.4% of theoretical.
Interference
The ability of a mercuric chloride-treated filter coupled with the glass fiber filter to collect phosphine was
tested when other potential interferences are present. Twelve samplers were used. The glass fiber filter of the
three samplers were spiked with 100 µL of 24 mg/mL ammonium phosphate dibasic. The glass fiber filter of the next
three samplers were spiked with 100 µL of 2.14 mg/mL DDVP in toluene. The remaining six samplers were used as
controls. They were used to sample an atmosphere containing 11.9 nmol/L (0.97 times the target concentration) of
phosphine at an absolute humidity of 15.5 milligrams of water per liter of air (70.9% relative humidity at 24.1°C)
at 1.0 L/min for 240 minutes. All of the samples were immediately analyzed. The samplers with ammonium phosphate on
the glass fiber filter had collected an average of 100.7% of theory. The three samplers with DDVP on the glass
fiber filter had collected an average of 99.9% of theory. The six control samplers had collected an average of
101.1% of theory.
Table 4.8.1
Interference Tests for hosphine
|
interference, amount placed
on the front filter |
recovery(%) |
average
recovery (%) |
|
ammonium phosphate,
dibasic, 2.4 mg |
101.2 |
99.6 |
101.4 |
100.7 |
| |
| DDV, 0.214 mg |
102.7 |
96.7 |
100.2 |
99.9 |
| |
| control |
93.3 |
105.7 |
103.1 |
101.1 |
| 102.1 |
100.4 |
102.1 |
|
Shelf life of the coated filter
The shelf life of the mercuric chloride-treated filter was tested by comparing the sampling recoveries of the 112-day-old
filters with the 6-day-old ones. Three samplers from each set were used to sample an atmosphere
containing 12.9 nmol/L (1.05 times the target concentration) of phosphine at an absolute humidity of 15.1 mg of
water per liter of air (72.2% relative humidity at 23.3°C) at 1.0 L/min for 245 minutes. The average recovery from
the 112-day-old filters was 83.5%. The average recovery from the 6-day-old filters was
93.4%. The filter is good for three months.
Table 4.8.2
Comparison of Old and New Filters
|
| age of filters |
recovery (%) |
average (%) |
|
| 112 days |
80.2 |
92.3 |
77.9 |
83.5 |
| 6 days |
94.3 |
94.5 |
91.3 |
93.4 |
|
1. Chughtai, M.; Pridham, P. N.; Cooke, M. Determination of phosphine by packed column gas
chromatography with alkali flame ionization detection. Analytical Communications, 1998, 35, 109-111.
2. Yang, G. and Dai, X. Huanjing Baohu (Beijin), 1994, 59(12), 21-22.
3. Wang, G.; Gao, Y.; Jiang, X.; Xiah, Y. Determination of phosphine in air by flame-photometric
gas chromatography. Weisheng Yanjiu, 1994, 23(2), 65-67; Chem. Abstr., 121, 116336.
4. Phosphine, Method 6002, NIOSH Manual of Analytical Methods, Fourth Edition. 1994.
5. Ku, J. Phosphine in Workplace Atmospheres. OSHA Analytical Method, ID-180,
1988, modified, 1991.
6. Greenfield, S.; Moule, H. A.; Perry, R. The Conductimetric Determination of Microgram
Amounts of Phosphine in Air. Analyst, 1966, 9, 10-14.
7. They proposed this reaction based on the amount of hydrogen chloride generated. The
precise nature of the phosphorus containing entity is not certain.
8. Matsumura, Y.; Ono-Ogasawara, M.; Furuse, M. Adsorption Sampling of Phosphine and Some
Other Semiconductor Material Gases. Appl. Occup. Environ. Hyg., 1993, 8(4), 288-292.
Determination of Phosphine by Adsorption Sampling with Modified Silica Gel and Colorimetry of Phosphine.
Industrial Health, 1990, 28, 175-184.
9. Hamalova, M.; Hodslavska, J.; Janos, P. Determination of Phosphorus, Potassium, and
Magnesium in fertilizers by Inductively Coupled Plasma-Atomic Emission Spectroscopy and Comparison with
Other Techniques. J. AOAC International, 1997, 80(6), 1151-1155.
10. Aardis., J. D.; Baker, A. M. Monitoring of Fertilizer Plant Effluents for Phosphorus,
Sulfur, and Metals Using Inductively Coupled Plasma Emission Spectrometry. J. Assoc. Off. Anal. Chem., 1989,
72(5), 857-859.
11. Mortensen, G.; Pedersen, B.; Rietz, B. ICP-AES and colorimetry as analytical tools
for the determination of phosphorus containing compounds, including phosphine. Analytical Letters, 1989,
22(7), 1791-1806.
12. Sax's Dangerous Properties of Industrial Materials, 8th edition; Lewis, R. J.,
Ed.; Van Nostrand Reinhold: New York, 1992. Vol. 3, p 2783.
13. Rickelton, W. A. Phosphine and Its Derivatives, In Kirk Othmer Encyclopedia of
Chemical Technology, 4th edition; Kroschwitz, J. I., Howe-Grant, M., Eds,; John Wiley
& Sons: New York, 1996; Vol. 18, pp 656-668.
14. OSHA Regulated Hazardous Substances - Industrial Exposure and Control Technologies,
Government Institutes, Inc., Rockville, MD, 1990.
15. NIOSH Alert: Preventing Phosphine Poisoning and Explosions during Fumigation;
DHHS (NIOSH) Publication No. 99-126; U.S. Department of Health and Human Services, National Institute
for Occupational Safety and Health; Cincinnati, 1999, p 3.
16. Merck Index, 10th Edition; Windholz, M. Ed.; Merck & Co.: Rahway, NJ,
1983.
17. OSHA Salt Lake Technical Center, Chemical Sampling Information.
(accessed Dec 1999).
18. 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.
19. OSHA Salt Lake Technical Center, Inorganic Methods Evaluation Protocol.
(accessed Oct 1999).
20. The treated filter was prepared by the following procedure.
Thirty-seven-millimeter-diameter round filters were cut from a piece of polyester non-woven fabric (polyester
non-woven, ultra firm, Style #9260, Handler Textile Co., Consumer Product Div., 24 Empire Blvd., Moonachie, NJ
07074). The filters were washed (sonication) twice with methanol, three times with 10% nitric acid, twice with
deionized water, twice with methanol, and dried. A solution of 4.0 g of mercuric chloride and a small amount of
methyl orange in 40.0 mL of 95:5 (v/v) methanol/glycerol was prepared. Caution: Mercuric chloride is a poison
and slightly volatile at ordinary temperature. Forty cleaned filters were placed on a clean glass plate and, using an
Eppendorf pipet with a plastic tip, 0.95 mL of the mercuric chloride solution was applied to each filter. The filters
were allowed to dry in a hood for 30 min. The treated filters were stored in a sealed container in a refrigerator.
21. Ammonium phosphate and DDVP (2,2-dichlorovinyl dimethyl phosphate) were selected to
represent residual fertilizers and semi-volatile organo-phosphorus pesticides that may possibly interfere with the
sampling for phosphine during a grain fumigation operation. DDVP has a vapor pressure of 0.012 torr (1.6 Pa) at
20°C. (Documentation of the Threshold Limit Values and Biological Exposure Indices, Sixth Edition; American
Conference of Governmental Industrial Hygienists: Cincinnati, OH, 1991; p.446.)
22. Occupational Exposure to Hazardous Chemicals in Laboratories. Code of Federal
Regulations, Part 1910.1450, Title 29, 1998.
23. Merck Index, 10th Edition; Windholz, M. Ed.; Merck & Co.: Rahway, NJ,
1983, p 839.
24. Nowak, M.; Singer, W. Mercury Compounds. In Kirk-Othmer Encyclopedia of Chemical
Technology, 4th edition Kroschwitz, J. I.; Howe-Grant, M., Eds; John Wiley
& Sons: New York, NY, 1995; Volume 16, p 232.
25. 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.
26. OSHA Salt Lake Technical Center, Inorganic Methods Evaluation Protocol.
(accessed Oct 1999).
27. The test atmosphere was generated by diluting a stream of certified 524.6 ppm
phosphine in nitrogen (at a flow rate of 25.5 mL/min) with an air stream (at 38.38 L/min) from a Miller-Nelson
humid air generator. The temperature was 19.9°C and the barometric pressure was 86.8 kPa (651.3 mmHg). The phosphine
concentration was calculated to be 0.348 ppm or 12.4 nmol/L.
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