SKC 520-02A User Manual

CAPLUGS

EC-14

NAS-813-14

Operating Instructions

Tel: [phone] Fax: [phone] e-mail: [e-mail]

863 Valley View Road, Eighty Four, PA 15330 USA

Passive Sampler for Inorganic Mercury

Catalog No. 520 Series

Introduction

The 520 Series Passive Sampler for Inorganic Mercury is a lightweight, reusable
personal sampler designed to be worn in the breathing zone of individuals who
are potentially exposed to inorganic mercury vapor.

The sampler is comprised of a reusable housing and a replaceable sorbent cap­sule. The sample enters the sampler by positive controlled diff usion. The sorbent
is analyzed by fl ameless atomic absorption. The sampler housing can be cleaned
and reused with a new sorbent capsule. Validation of the SKC 520 Series Passive
Sampler for Inorganic Mercury is based on OSHA ID-140.

Collar clip

Protective cap

Reusable

housing

Diff usive barrier

Mesh screens

Sorbent capsule

Retainer ring

520-02, mesh side

Foam disc

faces diff usive barrier

Back cap

Figure 1. Complete Assembly of Passive Sampler for Inorganic Mercury

Specifi cations*

Sorbent: Anasorb® C300 (SKC proprietary sorbent; equivalent to

Background: 0.02 μg/200 mg section
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 Co-effi cient
of Variation: 6.1%

* Specifi cations are based on a study conducted by the Health and Safety Executive (HSE) in the U.K.

as an update to Method MDHS 16.

† Limits may vary with analysis and instrumentation.

Note: For sampling low levels of mercury, use a sorbent tube.

Hydrar

®

and Carulite®)

†

†

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 diff usive 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 fi nish
time on I.D. label. Note any other pertinent sampling information.

Avoid excessive agitation of the sampler.

For Analysis

1. As soon as possible a er sampling, take the sampler to a clean area. Remove
sorbent capsule by pulling off the back cap. Remove foam disk from back cap
and dispose 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 fi eld blank to a
qualifi ed 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. Re-assemble 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 a er the sampling period.

• Always clean the housing before reusing to guard against accidental carry-over from previous
sampling.

2

• Always replace the used foam disk in the back cap with a clean disk a er 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 aff ect the
diff usion co-effi cient. This eff ect is small but may be signifi cant if sampling at un-
usually high or low temperatures. The diff usion coeffi cient (D) is a function of the
absolute temperature (T) by the relation D T
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  /min. In very still air conditions (below 25  /min), the sampling
rate will drop by up to 30%. If very high wind velocities (in excess of 750  /min)
are expected, passive samplers should not be used.

Ambient Pressure Changes

The sampling rate varies with ambient pressure changes which aff ect the diff usion
co-effi cient. The diff usion coeffi cient 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 unaff ected by the
presence of other gases, including chlorine. Note, however, that complex interac­tions in the atmosphere may reduce the total free elemental mercury present to be
sampled.

1.5

. This factor is taken into account

oc

Analysis

Consult OSHA Method ID 140 and MDHS 16 for detailed analytical procedures.

Preparation of Samples

Open the sorbent capsule and carefully pour the sorbent into a 50-ml volumetric
fl ask. Add 5 ml of concentrated nitric acid followed by 5 ml of concentrated hydro­chloric 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 fi ltration 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 chloride
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.

3

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 recom­mended that three diff erent 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
samples to check for any variations in response. Take particular care to avoid 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 Method ID 140 and MDHS 16 for detailed analytical procedures.

Interpretation of Results

The lab result will indicate the total mass of mercury which was 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:

-6

1. Convert reported mass of mercury into micrograms (10

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 = (T
T

= Sampling Site Temperature (K)

1

T

= 293 K

2

P

= Sampling Site Pressure (torr)

1

P

= 760 torr

2

4. Mercury mg/m

3

= Mercury Mass (μg) - Mercury Blank (μg)

1/T2

1.5

)

x (P2/P1)

Sample Volume (L)

Note: This is the calculation of mercury concentration as given in OSHA Method 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

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 com­plete SKC Limited Warranty and Return Policy, go to h p://www.skcinc.com/
warranty.asp.

Form 3758 Rev 1302