RA-915+ Portable Mercury Vapor Analyzer
Description
RA-915+ Portable Mercury Vapor Analyzer
  • 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
Optional Attachments

RA-915+ with RP-91C Attachment for solid samples analysis
RA-915+ with RP-91C Attachment for solid samples analysis
RA-915+ with RP-91 Attachment for water solutions analysis
RA-915+ with RP-91 Attachment for water solutions analysis
Features
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, o+ and o-, 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 o+ and o-, 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.
Water Analysis
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.
Analysis
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 800ºC, 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
Size and weight (with a storage battery and recharger) 460x210x110mm, 7.58 kg
Power requirements 110/220V, 50/60Hz 15W AC or 10-14V DC
Characteristics
Samples Detection Limit Sample Volume or Weight Atomization Technique Number of Analysis 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 mcg/kg 10 mg pyrolysis 15
Solid and sediments 0.5 mcg/kg 200 mg pyrolysis 15
Urine 5 ng/l 1 ml cold vapor 15
Tissues 5 mcg/kg 10 mg pyrolysis 15
Hair 20 mcg/kg 10 mg pyrolysis 15
Blood 0,5 mcg/l 0.2 ml cold vapor 15
Plants 2 mcg/kg 50 mg pyrolysis 15
Foodstuff 2 - 10 mcg/kg 5 - 50 mg pyrolysis 15