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RA-915+ Portable Mercury Vapor Analyzer
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Description
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- Direct detection of mercury without its preliminary accumulation on a gold sorbent
- Extremely low mercury detection limit and high selectivity
- Field operation from a built-in battery for mercury detection in atmospheric air and industrial gases
- Totally automated unattended stand-alone mode of operation for continuous monitoring of the environment for mercury pollution
- Ultra low mercury detection limit in water
- Streamlined design configured to a small-size and lightweight single portable unit
- Built-in microprocessor, LC display and computer interface for optional customized report output and storage in a stand-alone computer
- Optional attachments using the «cold vapor» technique for assaying water solutions and the pyrolysis with afterburning for assaying solid samples of complex composition
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| RA-915+ with optional attachments: |
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RA-915+ with RP-91C Attachment
for solid samples analysis |
RA-915+ with RP-91 Attachment
for water solutions analysis |
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The RA-915+ mercury analyzer employs differential atomic absorption
spectrometry technique, which is implemented using the direct Zeeman
effect (Zeeman Atomic Absorption Spectrometry using High Frequency
Modulation of Light Polarization ZAAS-HFM).
A glow discharge mercury lamp is placed in a permanent magnetic field,
whereby the 254-nm mercury resonance line is split into three polarized
components, only two of those, σ+ and σ-, which are circularly polarized
in the opposite directions, being detected for analysis.
After passing through a polarization modulator, which modulates
the polarization at a frequency of 50 kHz and thus
triggers the line components in turn, the radiation then
passes through a multi-path cell, whose equivalent
optical length is about 10 m. Being equipped with
narrow-band high reflectivity mirrors, the cell isolates
solely the 254-nm resonance line and suppresses all
the nonresonance and stray radiation.
A logarithm of the intensity ratio of σ+ and σ-,
which is proportional to the mercury atom concentration
in the cell, is determined upon detecting
the radiation by a photodetector and subsequent
analog-digital conversion of its electric signal
by a built-in microprocessor. The measurement
results are read out from a built-in LC display,
or are transmitted to a computer for further processing
or data storage. In this measurement technique,
the analytical signal depends only on mercury concentration and is
independent of the presence of dust, aerosols
, and other foreign contaminants in the analytical cell.
An RP-91 attachment is used for the mercury
determination in water by the «cold vapor» technique.
A reducing agent, SnCl2, is added to a sample,
and the atomic mercury thereby released is conveyed
to the analytical cell by a carrier gas.
The ultimate mercury detection limit in water
solutions is 0.6 ppt (ng/l), the sample volume being 10 ml
and the analysis time being no more than 90 sec.
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Analysis of complex matrix samples
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An analysis is carried out using an RP-91C attachment, wherein mercury is converted from a bound state to the atomic state by thermal decomposition in a two-section atomizer. The sample is vaporized in the first section, and the mercury compounds are partly decomposed. In the second section, which is heated to 800° C, the mercury compounds become fully decomposed, organic compounds and carbon particles are catalytically after burnt, to carbon dioxide and water. This technique is used to determine mercury in soils, food products, biological samples, and crude hydrocarbon products, no preliminary sample mineralization being needed and the analysis itself taking 1-2 minutes.
| Specifications
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Size and weight (with a storage battery and recharger) |
460x210x110mm, 7.58 kg |
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Power requirements |
110/220V, 50/60Hz 15W AC or 10-14V DC |
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| Analytical characteristics
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| Samples |
Detection limit |
Sample volume or weight |
Atomization technique |
Number of analyses per hour |
| Ambient air |
2 ng/m3 |
20 l/min |
without atomization |
*) |
| Natural and other gases |
2-500 ng/m3 |
5 - 20 l/min |
without atomization |
*) |
| Water |
0.5 ng/l |
20 ml |
cold vapor |
15 |
| Oil and condensate |
50 µg/kg |
10 mg |
pyrolysis |
15 |
| Solid and
sediments |
0.5 µg/kg |
200 mg |
pyrolysis |
15 |
| Urine |
5 ng/l |
1 ml |
cold vapor |
15 |
| Tissues |
5 μg/kg |
10 mg |
pyrolysis |
15 |
| Hair |
20 µg/kg |
10 mg |
pyrolysis |
15 |
| Blood |
0,5 µg/l |
0.2 ml |
cold vapor |
15 |
| Plants |
2 µg/kg |
50 mg |
pyrolysis |
15 |
| Foodstuff |
2 - 10 µg/kg |
5 - 50 mg |
pyrolysis |
15 |
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*) Real-time assaying with a response time of 1 sec.
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RA-915+ Documents Download |
View/Download Application notes in PDF format:
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