SKC 520 Series User manual

Passive Sampler for Elemental Mercury
Catalog No. 520 Series
Introduction
The 520 Series Passive Sampler for Elemental Mercury is a lightweight, reusable
personal sampler designed to be worn in the breathing zone of individuals who
are potentially exposed to elemental mercury vapor.
The sampler is comprised of a reusable housing and a replaceable sorbent capsule.
The sample enters the sampler by positive controlled diffusion. The sorbent is
analyzed by flameless atomic absorption. The sampler housing can be cleaned and
reused with a new sorbent capsule. Validation of the SKC 520 Series Passive Sampler
for Elemental Mercury is reported in OSHA Method ID-140.
Specifications*
Sorbent: Anasorb®C300 (SKC proprietary sorbent; equivalent to
Hydrar®and Carulite®)
Limit of Detection: 0.01 μg†
Limit of Quantitation: 0.04 μg†
Capacity: > 30 μg mercury per capsule
Breakthrough Volume: > 1500 liters of air
Overall Coefficient
of Variation: 6.1%
Sampling Rate: 0.020 L/min (20 ml/min) at 20 C and 760 torr (see page 4)
* Evaluated by the Health and Safety Executive (HSE) in the UK and reported in Method MDHS 16/2.
† Limits may vary with analysis and instrumentation.
Note: For sampling low levels of mercury, use a sorbent tube.
Figure 1. Complete Assembly of Passive Sampler for Elemental Mercury
Collar clip
Reusable
housing
Diffusive barrier
Mesh screens
Retainer ring
Sorbent capsule
520-02, mesh side
faces diffusive barrier
Foam disc
Back cap
Protective cap
Operating Instructions
863 Valley View Road, Eighty Four, PA 15330 USA
Tel: [phone] • www.skcinc.com

Preparing the Sampler
For Sampling
1. Remove the back cap from the housing with a screwdriver or a coin.
2. Remove a sorbent capsule from the plastic vial, and place it in the housing
with the mesh side facing the diffusive barrier.
Keep the plastic vial with remaining sorbent capsules in a safe place free from mercury
contamination.
3. Ensure the back cap contains a foam disk. Press the back cap onto the housing.
4. Record I.D., date, and start time on a provided I.D. label (included with
replacement sorbent capsules), and place it on the sampler’s back cap. Note
any other pertinent sampling information.
5. Using the clip, aach to clothing of individual near breathing zone or place in
desired location for area sampling.
6. To begin sampling, remove protective cap. Retain the cap in a safe place free
from contamination. Recommended sampling time is four to eight hours.
7. When sampling period is complete, replace protective cap and record finish
time on I.D. label. Note any other pertinent sampling information.
Avoid excessive agitation of the sampler.
For Analysis
1. As soon as possible after sampling, take the sampler to a clean area. Remove
sorbent capsule by pulling offthe back cap. Remove foam disk from back cap
and dispose of properly.
2. Place the sorbent capsule in the provided ziploc bag. Remove the I.D. label
from the sampler’s back cap and adhere to the ziploc bag.
3. Mail or transport the sorbent capsule and at least one field blank to a
qualified laboratory for analysis. The sorbent should be analyzed within
30 days of sampling.
Store sample away from sources of contamination.
For Cleaning
1. Unsnap and remove the collar clip. Clean with soap or detergent and water.
2. Disassemble the sampler and place all parts (except foam disk, sorbent
capsule, and collar clip) in a container. Wash in a dilute solution of nitric acid
(approximately 15%) in distilled water.
3. Rinse parts three times in separate rinses of distilled water.
4. Dry as quickly as possible.
5. Reassemble sampler housing for storage, without the sorbent capsule or foam
disk (see Figure 1).
6. Store in a clean area where the sampler will not become contaminated with
mercury until ready to use again.
• Always use a sorbent capsule within a few days of removing it from the plastic vial and placing
it in the housing; the protective cap does not provide a hermetic seal.
• When inserting a replacement sorbent capsule, ensure that the two mesh disks are in place
within the housing. These disks must be kept in place at all times to ensure reproducible
sampling rates under all environmental conditions.
• Do not store any parts of the sampler in areas where they may become contaminated with
mercury.
• Store the exposed sorbent capsule in the provided ziploc bag after the sampling period.
• Always clean the housing before reusing to guard against accidental carry-over from previous
sampling.
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• Always replace the used foam disk in the back cap with a clean disk after cleaning the housing.
• This sampler only samples elemental mercury (Hg) in the vapor phase and does not sample
organic mercury compounds or particulate maer.
• Take precautions when sampling for mercuric chloride. It can collect on the face of the badge and
interfere with sampling.
Interferences During Sampling
Ambient Temperature
The sampling rate will vary with ambient temperature changes which affect the
diffusion coefficient. This effect is small but may be significant if sampling at un-
usually high or low temperatures. The diffusion coefficient (D) is a function of the
absolute temperature (T) by the relation D T1.5. This factor is taken into account
in the calculation used in the OSHA method (see page 4).
Wind Velocity
The sampling rate will remain substantially constant over a range of wind velocity
from 25 to 750 ft/min. In very still air conditions (below 25 ft/min), the sampling
rate will drop by up to 30%. If very high wind velocities (in excess of 750 ft/min)
are expected, passive samplers should not be used.
Ambient Pressure Changes
The sampling rate varies with ambient pressure changes which affect the diffusion
coefficient. The diffusion coefficient is inversely proportional to the ambient pres-
sure. This factor is taken into account in the calculation used in the OSHA method
(see page 4).
Presence of Other Gases
The sampling of mercury on the sorbent has been shown to be unaffected by the
presence of other gases, including chlorine. Note, however, that complex interac-
tions in the atmosphere may reduce the total free elemental mercury present to be
sampled.
Analysis
Consult OSHA ID-140 and MDHS 16/2 for detailed analytical procedures.
Preparation of Samples
Open the sorbent capsule and carefully pour the sorbent into a 50-ml volumetric
flask. Add 5 ml of concentrated nitric acid followed by 5 ml of concentrated hydro-
chloric acid. Allow to stand for approximately 30 minutes or until the sorbent is
fully dissolved. Stir gently if necessary. Add approximately 15 ml of distilled water
to bring total liquid quantity up to 25 ml.
When Anasorb C300 is dissolved, a milky suspension results. This is an insoluble
residue and must be removed by filtration or centrifugation before analysis.
Take aliquots from this solution and analyze at 253.7 nm by cold vapor atomic
absorption.
Prepare several “blanks” by dissolving fresh, unexposed capsules of the same lot
number as the test specimen. These “blank” values represent the background level
of mercury in the sorbent and should be subtracted from all readings.
Mercury Desorption
The basic mechanism of desorption consists of adding an excess of stannous chlo-
ride to the aliquot of sample solution. This causes the mercury to be released as
elemental mercury, which is swept into the analyzer by an air or nitrogen stream.
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Calibration
The complete analytical system can be calibrated by injecting aliquots from standard
solutions (either from liquid or sorbent solution standards or both). It is recom-
mended that three different concentrations be checked to insure linearity of the
equipment over the likely range.
It is further recommended that standards and blank values be interspersed between
samplestocheckfor anyvariationsin response.Take particularcare toavoid buildup
of mercury on the internal surfaces of the equipment; this will cause an increase
in readings. A buildup of mercury can be detected by a gradual apparent increase
in the blank values during use. If this occurs, run several aliquots of mercury-free
solutions through the equipment until the analyzer indication drops to zero. Retest
the “blank” solution as an additional precaution before proceeding.
Report all results as nanograms or micrograms of mercury on the capsule by direct
comparison with the known standards. Relate the aliquot size to the total 25 ml of
liquid solution.
Consult OSHA ID-140 and MDHS 16/2 for detailed analytical procedures.
Interpretation of Results
The lab result will indicate the total mass of mercury collected on the sorbent
capsule in either nanograms (10-9 gram) or micrograms (10-6 gram). The airborne
concentration of mercury is determined as follows:
1. Convert reported mass of mercury into micrograms (10-6 gram).
2. Convert sampling period into minutes.
3. Sample Volume (L) =
Sampling Period x Sampling Rate x Temperature/Pressure
(mins) (L/min) Correction Factor
Where:
Sampling rate = 0.020 L/min at 20 C and 760 torr
Temperature/Pressure Correction Factor = (T1/T2)1.5 x (P2/P1)
T
1= Sampling Site Temperature (K)
T
2= 293 K
P
1= Sampling Site Pressure (torr)
P
2= 760 torr
4. Mercury mg/m3= Mercury Mass (μg) - Mercury Blank (μg)
Sample Volume (L)
Note: This is the calculation of mercury concentration as given in OSHA ID-140 (Revised
June 1991), page 16.
Ordering Information
Replacement Sorbent Capsules contain Anasorb C300* and
include replacement foams and resealable bags .................................. Cat. No. 520-02A/10
Cat. No. 520-02C/30
Reusable Capsule Holder ..........................................................................Cat. No. 520-03
* Anasorb C300 is equivalent to Hydrar and Carulite
Form 3758 Rev 1809
SKC Limited Warranty and Return Policy
SKC products are subject to the SKC Limited Warranty and Return Policy, which
provides SKC’s sole liability and the buyer’s exclusive remedy. To view the com-
plete SKC Limited Warranty and Return Policy, go to hp://www.skcinc.com/
warranty.