CETAC M-7600 Mercury Analyzer Operator's Manual

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Operator’s Manual Chapter 4: Using the Analyzer Ultimately, the gas stream (carrier gas and Hg 0 ) exits the sample cell (15) and is exhausted to a solid KMnO 4 trap (16) where Hg 0 is absorbed, and clean carrier gas passes to the lab atmosphere. Dryer Cartridge The mercury analyzer uses a Perma Pure ® DuPont Nafion ® -based dryer cartridge. Dryer cartridges typically last three to six months. The dryer cartridge contains Perma Pure ® dryer tubing which is made with a tubular DuPont Nafion ® membrane. The Nafion ® tubing is housed within an outer tube and coiled inside the cartridge. The argon or nitrogen carrier gas containing mercury and water vapor is swept along the inner Nafion ® membrane, allowing water vapor to permeate the membrane selectively, whereas the membrane is not permeable to mercury vapor. On the “waste” side of the membrane, a counter gas flow, split from the carrier gas supply, selectively sweeps the water vapor out of the system, whereas non-permeating mercury vapor proceeds to the sample cell. The Perma Pure ® dryer cartridge and associated plumbing is already preinstalled in your new QuickTrace M-7600 factory shipment. No further installation is required. Optics and Cold Vapor AAS Refer again to Figure 4-1 on page 76 to trace the optical path of the QuickTrace M-7600. The Cold Vapor AAS (Atomic Absorption Spectrometry) process within the sample cell begins with a low pressure, high frequency, thermally stabilized, electro-optically regulated Hg vapor lamp, which produces the Hg emission spectrum. Emitted light is collimated (L 1) and projected in two parallel, isolated beams one each through the reference and sample cells. Absorbance of 253.7nm radiation by Hg 0 vapor (derived from the chemically reduced sample and GLS) occurs only in the sample cell. P is thereby decreased, relative to P 0. Light from the cells enter the binocular camera, where both collimated beams are independently focused (L 2) and filtered (F) before reaching the Charged Coupled Device (CCD) detector. Narrow band 254 +/- 2nm interference filters (F) remove all radiation but the strong 253.7 nm Hg 0 “resonance line” from both the sample (P) and reference (P 0) beams. By a photovoltaic effect, the CCD converts the light beams into electrical signals, proportional to radiant power (P and P 0). These outputs are processed to yield an electrical signal proportional to optical absorbance (Abs = -log (P/P 0)). Software In the host computer, the sample absorbance value is drift corrected, blank subtracted, if through blank is desired. The absorbance value is then measured against a calibration curve derived from previously obtained absorbance values of calibration standards. The QuickTrace software operates under a Windows environment. The QuickTrace software provides complete instrument, autosampler control. The QuickTrace software also provides a variety of EPA compliant quality control functions, display features, report generation and diagnostic routines. 78
CETAC QuickTrace M-7600 Mercury Analyzer Chapter 4: Using the Analyzer The user interface is sufficiently powerful that it will satisfy the requirements of experienced technically advanced analysts and scientists. The reader is referred to the separate QuickTrace Help file and QuickTrace Mercury Analyzer Software Manual for a detailed description of the software features, functions, and operation instructions. Preparing Reagents and Calibration Standards Always use high purity gas, chemicals, acids, water, standards, and clean glassware for analysis. It may be necessary to acid wash and rinse all glassware more than once to eliminate contamination for the most sensitive mode of operation (
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CETAC M-7600 Mercury Analyzer Opera
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Contents 1 Introduction ...........
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M-7600 Mercury Analyzer Operator's
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1 Introduction Overview The CETAC Q
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CETAC QuickTrace M-7600 Mercury Ana
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2 Preparing for Installation Instal
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3 Installing the Analyzer Installat
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Page 103 and 104: 5 Maintaining the Mercury Analyzer
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6 Troubleshooting the Mercury Analy
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8 Glossary A Amperes, electrical cu
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ng Nanogram (10 -9 gram), mass or w
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Index autosampler data cables, 44,
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Manual Part Number 480195 Rev 2 Pri
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CETAC M-7600 Mercury Analyzer Operator's Manual

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