Cold Vapor Atomic Fluorescence Mercury Analyzer

What is the Cold Vapor Atomic Fluorescence Mercury Analyzer?

A cold vapor atomic fluorescence mercury analyzer detects the fluorescence of mercury atoms after reduction and amalgamation. It is chosen for ultratrace mercury with detection limits far below absorption methods in water and seawater.

Overview

Mercury vapor is generated by reduction and concentrated on a gold trap, then thermally desorbed into a fluorescence cell. A mercury lamp or other source excites the atoms at 253.7 nanometres, and a photomultiplier placed at right angles to the excitation beam measures the emitted fluorescence, which is proportional to concentration at low levels. Because the detector looks at a dark background, sensitivity is much higher than in atomic absorption, and detection limits reach 0.1 to 1 nanogram per litre for water. This performance makes atomic fluorescence the preferred principle for ultratrace water, seawater and ice core studies under methods such as US EPA Method 1631. The gold trap also removes interferences and concentrates mercury from large sample volumes. Systems can be automated with autosamplers and calibration using gas-phase mercury generators.

How does it work?

Mercury is unique among metals because it is volatile at room temperature and forms a stable amalgam with gold. Most analyzers exploit one or both properties. In cold vapor atomic absorption, mercury in solution is reduced to elemental form with tin chloride or sodium borohydride and swept into an absorption cell where it absorbs the 253.7 nanometre line of a mercury lamp. Cold vapor atomic fluorescence uses the same generation step but detects emitted light at right angles for higher sensitivity. Direct analyzers heat the solid or liquid sample to release mercury, which is collected on a gold amalgamator, then desorbed into a detector. Ambient air and emission monitors use gold amalgamation or optical techniques such as Zeeman atomic absorption or ultraviolet absorption for continuous measurement. Calibration uses certified mercury standards and gas-phase generators, and all systems require careful control of contamination because mercury is ubiquitous in laboratories.

What are the key features?

• Gold amalgamation and thermal desorption
• Right-angle fluorescence detection for low background
• Detection limits down to 0.1 ng/L in water
• Suitable for purge-and-trap ultratrace methods
• Gas-phase mercury generator calibration
• Optional autosampler for long sequences

What are the technical specifications?

A typical cold vapor atomic fluorescence mercury analyzer configuration offers detection limit of 0.1–1 ng/L in water, measurement range of 0.5–100 ng/L, wavelength of 253.7 nm excitation and emission, detection of photomultiplier, right angle, amalgamation of gold trap and reductant of tin chloride or borohydride. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Cold Vapor Atomic Fluorescence Mercury Analyzer is used in ultratrace mercury in drinking water and seawater, ice core and atmospheric deposition studies, estuarine and ocean mercury cycling and certified reference material characterization. Across the wider Mercury Analyzers class, laboratories also deploy it for mercury in fish, rice, seafood and food products, drinking water, wastewater and seawater monitoring and soil, sediment and contaminated site assessment.

Which standards and certifications apply?

Relevant standards and methods include US EPA Method 7473 Mercury in solids and solutions by thermal decomposition, US EPA Method 7470A Mercury in liquid waste by cold vapor AAS, US EPA Method 1631 Mercury in water by oxidation, purge and trap, and CVAFS, ISO 12846 Water quality — Determination of mercury by AAS after enrichment, ISO 20552 Workplace air — Determination of mercury vapour by gold amalgamation, EN 15852 Stationary source emissions — Determination of total gaseous mercury and IEC 61010-1. Certification candidates for this model are CE, ISO 9001 manufacturing and IEC 61010-1 safety compliance; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Mercury is toxic by inhalation and accumulates, so laboratories must control vapor exposure, use ventilated enclosures and monitor ambient air. Contamination is a constant risk because mercury appears in reagents, dust and previous samples, so ultrapure reagents, dedicated glassware and rigorous blanks are essential. Gold amalgamators require periodic cleaning or replacement when recovery falls. Calibration standards and gas generators must be traceable, and reducing agents must be fresh. Luminaires and detectors for the 253.7 nanometre line need stable temperature. For emission and ambient monitors, sample lines must be heated and inert to prevent mercury loss. Maintain service records and follow local occupational exposure limits and waste disposal rules.

How do I select the right Cold Vapor Atomic Fluorescence Mercury Analyzer?

Select cold vapor atomic fluorescence when the lowest possible mercury detection limits are required, for example ultratrace water, seawater or climate studies. Specify the sample volume, expected range and whether a specific method such as US EPA Method 1631 must be followed. Confirm clean-room capability, because contamination defines the achievable limit.

How does it compare with other Mercury Analyzers variants?

Select a mercury analyzer by sample type and required detection limit. Direct thermal decomposition analyzers handle solid and liquid samples in minutes with minimal preparation and reach low nanogram levels, which suits food, soil and waste testing. Cold vapor atomic absorption is a robust, economical choice for water and digested samples at microgram per litre levels. Cold vapor atomic fluorescence reaches much lower limits and suits ultratrace water and seawater work. Portable ambient air analyzers with gold film or Zeeman detection serve workplace and indoor air surveys. Continuous emission monitors and total mercury analyzers with gold amalgamation are installed on industrial stacks and process streams. Confirm the measurement range, sample throughput, calibration approach and whether a specific regulatory method is mandated.