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These procedures were designed and tested for internal use by OSHA personnel. Mention of any company name or commercial product does not constitute endorsement by OSHA.
|Target Concentration:||350 ppm (1900 mg/m3) OSHA PEL|
|Procedure:||Collection on charcoal adsorbent, desorption with carbon disulfide, analysis by GC using a flame ionization detector.|
|Recommended air volume and sampling rate:||
3 L at 0.2 L/min
|Reliable quantitation limit:||0.07 ppm (0.4 mg/m3)|
|Standard error of estimate
at the PEL concentration:
|Status of method:||Evaluated method, This method has been subjected to the established evaluation procedures of the Organic Methods Evaluation Branch.|
|Date: January 1980||
Chemist: Duane E. Lee
Organic Methods Evaluation Branch
OSHA Analytical Laboratory
Salt Lake City, Utah
Outdated methods for the sampling and analysis of
The following information is taken directly from Reference 5.3.
1,1,1-Trichloroethane causes central nervous system depression.
A number of human fatalities related to industrial exposure in closed spaces have been reported, some of which may have been "sudden deaths" due to sensitization of the myocardium to epinephrine.
Based on effects caused in monkeys and rats, the following effects are expected in humans: 20,000 ppm for 60 min, coma and possibly death; 10,000 ppm for 30 min, marked incoordination; 2000 ppm for 5 min, disturbance of equilibrium. Human subjects exposed to 900 to 1000 ppm for 20 min experienced lightheadedness, incoordination, and impaired equilibrium; transient eye irritation has also been reported at similar concentrations.
A few scattered reports have indicated mild kidney and liver injury in humans from severe exposure; animal experiments have confirmed the potential for liver, but not for kidney, injury. Skin irritation has occurred from experimental skin exposure to the liquid and from occupational use. The liquid can be absorbed to a moderate degree through the skin.
In dogs, myocardial sensitization to epinephrine occurred at concentrations of 5000 to 10,000 ppm. In a carcinogenicity study, rats and mice were given the liquid orally at two different dose levels, five days a week for 78 weeks. Both female and male test animals exhibited early mortality compared with untreated controls, and a variety of neoplasms was found in both treated animals and controls. Although rats of both sexes demonstrated a positive dose-related trend, no relationship was established between the dosage groups, the species, sex, type of neoplasm, or the sites of occurrence.
The odor threshold has been described by various investigators as ranging from 16 to 400 ppm.
The TLV was set at a level to prevent mild irritation.
NIOSH estimates that there were 2.9 million workers exposed
1,1,1-Trichloroethane is mainly used as a solvent for cleaning and other solvent applications. There were 630 million pounds produced in 1976. (Ref. 5.5.)
|specific gravity:||1.3249 (26°C/4°C)|
|vapor density:||4.6 (air = 1)|
|vapor pressure:||127 mm Hg (25°C)|
|refractive index:||1.43765 (21°C)|
|saturated air:||16.7% (25°C)|
|saturated air density:||
1.6 (air = 1)
|solubility:||insoluble in water; soluble in ethanol and ethyl ether|
|Aerothene TT; Chloroethene NU; Chlorothene; Chlorothene NU; Chlorothene VG; Chlorten; Inhibisol; methyl chloroform; methyltrichloromethane; NCI-C04626; Alpha-T; trichlorethane; a-trichloroethane.|
The detection limit of the analytical procedure is 1.2 ng per injection. This is the amount of analyte which will give a well defined peak on the tail from the solvent peak. (Section 4.1.)
The detection limit of the overall procedure is 1.2 µg per sample (0.07 ppm or 0.4 mg/m3). This is the amount of analyte spiked on the sampling device which allows recovery of an amount of analyte equivalent to the detection limit of the analytical procedure. (Section 4.1.)
The reliable quantitation limit is 1.2 µg per sample (0.07 ppm or 0.4 mg/m3). This is the smallest amount of analyte which can be quantitated within the requirements of 75% recovery and 95% confidence limits of ±25%. (Section 4.2.)
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 concentration range representing 0.1 to 2.1 times the PEL concentration based on the recommended air volume is 53430 area units per mg/mL. The sensitivity is determined by the slope of the calibration curve. (Section 4.3.) The sensitivity will vary somewhat with the particular instrument used in the analysis.
The recovery of analyte from the collection medium must be 75% or greater. The average recovery over the range of 0.5 to 2 times the PEL is 99.6%. (Section 4.1.)
The pooled coefficient of variation obtained from replicate determinations of analytical standards at 0.5, 1 and 2 times the PEL concentration is 0.0086. (Section 4.3.)
The overall procedure must provide results at the PEL
concentration that are ±25% or better at the 95% confidence level. The precision at the
95% confidence level for the
If other compounds are present, the GC run time must be lengthened so the late eluting peaks will not interfere with the next sample.
Breakthrough tests were run on the primary portion of a
charcoal tube (SKC Lot 107) at a sampling rate of 0.2 L/min from a generated test
atmosphere. The test atmosphere was 708 ppm
The desorption efficiency from liquid injections on charcoal tubes (SKC Lot 107), averaged 99.6% for 2.98 to 11.9 mg per tube, which is 182 to 728 ppm for a 3-L air volume (Section 4.1.).
|helium (carrier gas) flow rate:||25.1 mL/min|
|hydrogen flow rate:||43 mL/min|
|air flow rate:||248 mL/min|
|injection size:||1 µL|
Usually the integrator is programmed to report results in ppm (corrected for desorption efficiency) for a 3-L air sample. The following calculation is used:
|ppm = (A)(3)/B||where||A = ppm on report
B = air volume, L
A small amount of analyte (1.2 ng/injection) which still
produced a well defined peak on the tail of the solvent peak was designated as the
analytical detection limit. This was determined with an analytical standard which
contained 0.009 µL of
Reproducibility of the peak, produced by replicate 1.2-ng injections, was good. Twelve injections gave an average analyte peak height of 35 mm with coefficient of variation of 2.4%.
A sample collected from 3 L of air which contained 1.2 ng/µL after desorption with 1 mL of carbon disulfide would represent an air concentration of 0.07 ppm.
Liquid injections were made on the front portion of charcoal tubes (SKC Lot 107) at 0.0012 to 11.92 mg. These charcoal tubes were refrigerated overnight and desorbed and analyzed the following day. These results are presented in Table 4.1.2. and in Figures 18.104.22.168. and 22.214.171.124. The overall detection limit was determined to be 1.2 µg/sample in Figure 126.96.36.199.
Desorption Efficiencies for Various Sampler Loadings
average desorption efficiency over the
range of 2980 to 11920 µg (0.5 to 2 times
the target concentration) is 99.6%.
The reliable quantitation limit was verified to be the same as the overall detection limit by liquid spiking six samples with loadings equivalent to the overall detection limit (1.187 µg/sample). These samples were analyzed to assure the requirements of at least 75% recovery with a precision (1.96 SD) of at least ±25% were met.
Reliable Quantitation Limit
X = 98.5
SD = 2.135
1.96(SD) = 4.2
Multiple injections were made of standards that were prepared over a range of 0.1 to 2.1 times the OSHA standard. A standard deviation was determined at each concentration. The pooled coefficient of variation was determined for the range.
|× target conc.
CV = 0.0086
Samples were collected on charcoal tubes (SKC Lot 107) from
a generated atmosphere containing 354 ppm
|(-4°C to 3°C)||
(18.2°C to 21°C)
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