|| 5 mg/m3 ACGIH TLV. There is no OSHA PEL for
|| Samples are collected by drawing known, volumes of air through OSHA
versatile sampler (OVS-2) tubes, containing a glass fiber filter and two
sections of XAD-2 adsorbent. Samples are
extracted with acetonitrile and analyzed by high performance liquid
using an ultraviolet (UV) detector.
|Recommended air volume and sampling rate:
|| 60 L and 1.0 L/min
|Detection limit of the overall procedure based on
the recommended air volume:
|| 0.02 mg/m3
|Status of method:
|| Stopgap method. This method has been only partially evaluated
and is presented for information and trial use.
||David B. Armitage
Carcinogen And Pesticide Branch
OSHA Analytical Laboratory
Salt Lake City, Utah
1. General Discussion
2. Sampling procedure
1.1.1 History of Procedure
1.2 Limit defining parameters
This evaluation was undertaken to determine the effectiveness of the OVS-2
sampling device for captan. It follows the procedure developed for
carbaryl. (Ref. 5.1)
It should be noted that in this evaluation for captan several other
analytes were also present in the analytical procedure. These other analytes
are not mentioned in this evaluation, but can be seen on the sample
chromatogram. (Sec. 3.5.2)
1.1.2 Toxic effects (This section is for information only and
should not be taken as the basis of OSHA policy).
The acute oral LD50 for rats is 12.5 ± 3.5 g/kg, with death
mostly occurring during the third and forth days. A National Cancer Institute
carcinogenesis bioassay completed in 1977 was positive for mice. However other bioassays for
mice and rats have been
negative. (Ref. 5.2)
There are indications that captan may cause skin irritation in some workers. (Ref.
Based on the available toxicity data captan has been given a TLV of 5 mg/m3 by
the ACGIH. (Ref. 5.2)
1.1.3 Potential workplace exposure
No estimate of worker exposure to captan could be found. The estimated
production of captan in 1972 was 17 million pounds. Captan is used as a
protectant-eradicant fungicide. (Ref. 5.3)
1.1.4 Physical properties (Ref. 5.3-5.6)
||white, crystalline, odorless solid
||in g/100 mL of solvent at 25ºC
||Captaf, Captex, Herpan, Orthocide, Pillarcap
The detection limit of the analytical procedure is 6 ng per injection. This
is the amount of analyte which will give a peak whose height is approximately five times the baseline noise.
3. Analytical procedure
2.1.1 Samples are collected by using a personal sampling
pump that can be calibrated to within + 5% of' the recommended flow rate with the
sampling device in line.
2.1.2 Samples are collected with OVS-2 tubes, which are specially made 13-mm o.d. glass tubes that are tapered to 6 mm o.d..
These tubes are packed with a 140-mg backup section and a 270-mg sampling
section of cleaned XAD-2. The backup section is retained by two foam plugs
and the sampling section is between one foam plug and a 13-mm diameter glass
fiber filter. The glass fiber filter is held next to the sampling section by
a polytetrafluoroethylene (PTFE) retainer.
Figure 2.1 OVS-2 Sampling Device.
No sampling reagents are required.
2.3 Sampling technique
2.3.1 Attach the small end of the OVS-2 sampling tube to
the sampling pump with flexible, plastic tubing such that the large, front
section of the sampling tube is exposed directly to the atmosphere. Do not
place any tubing in front of the sampler. The sampler should be attached
vertically (large end down) in the worker's breathing zone in such a manner
that it does not impede work performance.
2.4 Extraction efficiency
2.3.2 After sampling for the appropriate time, remove the sampling
device and seal the tube with plastic end caps.
2.3.3 Wrap each sample end-to-end with an OSHA seal (Form 21).
2.3.4 With each set of samples, submit at least one blank. The blank
should be handled the same as the other samples except that no air is drawn
2.3.5 Bulk samples should be submitted for analysis in a separate
container. Do not ship with the air samples.
Two 13-mm glass fiber filters were each liquid spiked with 299.2 µg of
captan. These two filters, along with a blank filter, were each placed in
separate 4-mL vials which also contained 270 mg of XAD-2 adsorbent. These
vials were stored overnight at room temperature, and then extracted with 2
mL of acetonitrile.
The average extraction efficiency for these two filters (with the XAD-2
adsorbent present) was 90%.
2.5 Retention efficiency
Two OVS-2 tubes were each spiked with 299.2 µg of captan by liquid spiking the 13-mm glass fiber filter. Sixty liters of humid air were
drawn through each tube. The two tubes were then extracted as in Section
3.4. No significant breakthrough to the
backup section was observed.
The average retention efficiency for these two tubes was 92%.
2.6 Sample storage
Two OVS-2 tubes were each spiked with 299.2 pg of captan
as above. Sixty liters of humid air were drawn through each tube. These two
tubes were stored for seven days at ambient temperature in a drawer. They
were then extracted as in Section 3.4. No captan was recovered from the backup section of these
The average recovery after seven days of storage was 82%.
2.7 Recommended air volume and sampling rate
2.7.1 The recommended air volume is 60 L.
2.7.2 The recommended flow rate is 1.0 L/min.
It is not known if any compounds will interfere with the collection of
captan. Suspected interferences should be reported to the laboratory with
2.9 Safety precautions
2.9.1 Attach the sampling equipment in such a manner that
it will not interfere with work performance or employee safety.
2.9.2 Follow all safety practices that apply to the work area
4. Recommendations for further study
3.1.1 A high-performance liquid chromatograph equipped
with a UV detector, and manual or automatic injector. A Waters M6000A pump,
Waters 710B autosampler, and Waters 440 UV detector with an extended
wavelength module were used in this evaluation.
3.1.2 An HPLC column capable of separating captan from any
interferences. A 25 cm × 4.6 mm i.d. DuPont Zorbax ODS (6 micron) column
was used in this evaluation.
3.1.3 An electronic integrator or other suitable means of
measuring detector response. A Hewlett-Packard 3357 data system was used
in this evaluation.
3.1.4 Vials, 4-mL glass with PTFE-lined septa.
3.1.5 Volumetric flasks, pipets, and syringes for preparing
standards, making dilutions, and performing injections.
3.2.1 HPLC grade acetonitrile (ACN).
3.3 Standard preparation
3.2.2 HPLC grade water. A Millipore Milli-Q
system was used to prepare the water for this evaluation.
3.2.3 Captan, 99% pure (Chem Services Inc.).
Stock standard solutions are prepared by adding acetonitrile to
preweighed amounts of captan. Working range standard solutions are prepared
by diluting stock solutions with acetonitrile. Stock and dilute standards
are stored in a freezer.
3.4 Sample preparation
3.4.1 Transfer the 13-mm glass fiber filter and the 270-mg
section of the sampling tube to a 4-mL vial. Place the first foam plug and
the 140-mg section in a separate vial. A small glass funnel can be used to facilitate the transfer of the
adsorbent. Discard the rear foam plug. Do not discard the glass sampling tube; it can be reused after it has been
cleaned with surfactant or suitable solvent.
3.4.2 Add 2.0 mL of acetonitrile to each vial.
3.4.3. Seal the vials with PTFE-lined septa and allow them to
extract for one hour. The vials should be shaken by hand periodically
during the one hour extraction time.
3.5.1 Instrument conditions
||25 cm × 4.6 mm i.d. stainless steel column, packed
with 6 micron DuPont Zorbax ODS
||45% ACN / 55% water (v/v)
Figure 3.5.2 Chromatogram of Captan (with other analytes)
3.6.1 Any compound having a similar retention time
to the analyte is a potential interference. Generally, chromatographic
conditions can be altered to separate an interference from the analyte.
3.6.2 Retention time on a single column is not proof of chemical identity. Analysis by an alternate HPLC column, detection at another
wavelength, comparison of absorbance response ratios, and confirmation by mass
spectrometry are additional means of identification.
3.7.1 A calibration curve is constructed by plotting
detector response versus standard concentration.
3.8 Safety precautions
Figure 3.7.1 Calibration Curve for Captan
3.7.2 The concentration of captan in a sample is determined from
the calibration curve. If captan is found on the backup section, it is added to
the amount found on the front section. Blank corrections for each section should
be performed before adding the results together.
3.7.3 The air concentration is then determined by the following formula:
||(µg/mL in sample) × (extraction volume, mL)
(air volume, L) × (extraction efficiency, decimal)
3.8.1 Avoid exposure to all standards.
3.8.2 Avoid exposure to all
3.8.3 Wear safety glasses at all times.
There appears to be some loss of captan with storage at ambient temperature.
A more statistically valid storage study should be done to clarify this
tendency. This method should be fully validated.
5.1 Burright, D., Method #63,
"Carbaryl (Sevin)", OSHA Analytical Laboratory, unpublished,
5.2 "Documentation of the Threshold Limit Values and
Biological Exposure Indices", American Conference
of Governmental Industrial Hygienists Inc., fifth edition,
5.3 "Substitute Chemical Program, Initial Scientific and
Minieconomic Review of Captan", U.S. Environmental Protection Agency,
Office of Pesticide Programs, Criteria and Evaluation Division, Washington, D.C., April
5.4 "Farm Chemicals Handbook", Meister Publishing Co.,
5.5 Windholz, M., Ed."Merck Index", 10th ed.; Merck and Co., Rahway, NJ, 1983.
5.6 "Chemical Information File", U.S. Department of Labor, Occupational
Safety and Health Administration, Directorate of Science, Technology and Medicine, June 14,