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RA-4300FG+

Reducing-Vaporization Mercury Analyzer

Highly sensitive and cost-effective

RA-4300 is an automated, Reducing Vaporization – Gold Amalgamation – Cold Vapor Atomic Fluorescence Spectroscopy (CVAFS) mercury analyzer from NIC to provide Ultra-Trace Level of Mercury Analysis.

Applications

Rainwater, seawater, and any water samples require a sub ppt level of mercury measurement

Methods

USEPA 1631e  |  USEPA 245.7  |  ISO 17852  EN-1483

Features

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QA/QC Validation Program – Put Your Mind at Ease with EPA 1631e Requirements

The operating software of RA-4300FG+ comes with the USEPA 1631e comprehensive formal quality assurance and control package set as per method criteria as default. Users can adjust the limits in accordance with their laboratory criteria, if necessary.

(a) Calibration

(b) Initial precision and recovery

(c) Analysis of blanks

(d) Matrix spike/matrix spike duplicate analysis

(e) Ongoing precision and recovery

(f) Quality control sample

(g) Method detection limit

RA-4300FG+
- Automating the “Purge & Trap Oxidation”

RA-4300FG+ is ingeniously engineered to the requirements of EPA 1631E.

Sample digestion and oxidation processes are automated:

Extremely Clean Analysis Environment
- Built-In Mercury Removal Filter

Ultra-trace level of mercury analysis requires demanding cleanliness of ambient condition, especially environmental air.
RA-4300FG+ is designed with a clean chamber concept with an integrated innovative Carbon-Layered-Mesh mercury removal filter. All ambient air goes through this mercury removal filter, removing both micro-dusts and mercury where only mercury-free air is introduced into the system chamber.

This feature ensures all samples in sample tubes are kept clean at all times throughout the analysis process.

Superior Detection Limit and Sensitivity
– Detection Limit Down to 0.05 ppt

RA-4300FG+ is equipped with the latest and ultra sensitive CVAFS available which has detection down to 0.05 ppt (0.5 ppt including sample digestion process of EPA 1631e) with excellent accuracy and precision.

With this superior detection limit and excellent precision, the RA-4300FG+ is capable to satisfy a wide range of analysis applications such as snow water, seawater, rainwater and underground springs where mercury contents are in ultra-trace level.

High Productivity
- Autosampler with 80 Positions

RA-4300FG+ is equipped with an autosampler of 80 positions which maximizes the throughput of any fast-paced laboratory, providing results with the shortest turnaround time possible.

Superior Reducing Vaporization by Discrete-Direct-Purge Technique

Generally, there are two methods of Reducing Vaporization, i.e.,

  • Flow Injection Technique
  • Discrete-Direct-Purge Technique.

All mercury analyzers in NIC employ Discrete-Direct-Purge Technique to minimize memory effect from mercury which causes cross-contamination issue.

Lower Operation Cost
– Reduced Consumption of High Purity Reagents

When it comes to ultra-trace level of mercury analysis, the purity of reagent plays a vital role to have minimum interference to the analyte measurement. Consumption of reagents directly relates to the daily operating cost. By having the discrete-direct-purge technique in RA-4300FG+, all reagents used are reduced proportionally.

RA-5A

Compact A4 size, modular CVAAS mercury analyzer. Tailored to accommodate different needs of each laboratories.

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Other Series

MA Series

A state-of-the-art Direct Mercury Analyzer

  • No sample digestion needed
  • Fast analysis time
  • Highly accurate
  • Solid , liquid, gaseous matrices

PE Series

In full compliance with UOP-98-20, PE Series can fulfill all analysis requirements of liquid hydrocarbon samples.

WA Series

Mercury analyzer for ultra-trace level analysis in gaseous matrices. Featuring Dual Gold Amalgamation technique and various capacity options.

Differences between NIC Discrete-Direct-Purge Reducing Vaporization and other reducing vaporization techniques

NIC’s Discrete Direct-Purge Reducing Vaporization

In this technique, the mercury analyzer handles each sample in a Discrete, independent sample tube. Each sample is therefore isolated from surface contact with any other samples in the analytical batch to be measured.

The Direct-Purge technique is then used to extract and transfer the converted Hg0 from each sample tube and into the detector for measurement. Since only mercury vapor contacts the flow path, sample-to-sample memory effects and carryover from over-range samples are virtually eliminated.

How It Works

  • First, reductant (SnCl2) is automatically added into the sample tube containing the acid-digested sample solution. The sample tube is sealed, leaving a closed-loop flow path to the detector.
  • The carrier gas is introduced to sparge (or purge) the solution, releasing the elemental mercury vapor from the solution and into the flow path, which then flows directly into the detector for measurement.

Advantages

  • Almost no sample-to-sample carryover or memory effect
  • Carryover from over-range samples is greatly reduced
  • Discrete technique only needs 200-300uL of reagent per sample
  • Reduces hazardous mercury wastes to less than one liter per full day of operation
  • Filtration of samples not required, as Direct-Purge technique can handle particulates in samples with no issues

Other Reducing Vaporization Techniques

  • Commonly based on Flow-Injection or Continuous-Flow Techniques to introduce the full sample solution into the system to complete the chemical reaction for the analysis.
  • The acidic sample solutions and reductant (SnCl2) enter the system via pump tubing with peristaltic pumping, which must be replaced often.
  • Chemical reduction begins when both the sample solution and reductant are mixed, reducing Hg2+ into Hg0, within a continuous flow of reagents.
  • Prior to the detector, the liquid-gas phase separator or membrane separation device is needed to remove the liquid, allowing the Hg0gas to enter the detector.

Mercury is well-known for its strong affinity to absorb onto different materials and its high solubility in acidic reagents.

After the digestion and oxidization procedure, samples are usually very acidic. The acidic sample solutions and reductant, SnCl2, enter the system via pump tubing with peristaltic pumping. The acidic sample leaves a residue on the inner surface of pump tubing, creating possible active sites for mercury absorption from current mercury, which is easily passed on to the following samples.

Such phenomenon is inevitable with this technique and commonly exhibits as what is called the mercury memory-effect, experienced by many lab analysts. This effect is especially significant and severe when analyzing samples of varying mercury concentration levels.

Large multi-liter carboys of hazardous waste are produced daily from such flow-based techniques, creating the need for expensive waste disposal. Reduction of hazardous mercury wastes should be a priority for all mankind, and it is a priority of the Minamata Treaty

How Does it Reduce Reagent Consumption?

Less Reagent Consumption, Less Waste Generation Compared to Flow-Injection Technique

Generally, the flow-technique system continuously pumps and flows the reagents through the system to stabilize the dynamic flow to get a consistent flow (sample) volume which is crucial for precise quantification purposes. Secondarily, the reagents used for the analysis are pumped continuously through the system to clean the flow paths and obtain a constant background. Overall, multiple milliliters per minute of liquids are used and generated as waste.

In discrete-direct-purge technique, much lesser reagents are consumed. This technique uses a fixed volume of reagents per sample analysis. Typically, only just 0.3 milliliter of reductant (SnCl2) is consumed per run.

Less usage of reagents which are generally acidic, generates less hazardous waste for disposal, saving the operating cost in both ways.

Similarly, for sample solution, NIC reducing vaporization normally uses fixed 5mL sample volume for analysis. As for flow technique, sample solution is continuously pumped through the system to complete the reaction with the reductant. Depending on the flow rate setting, typically each analysis generates between 7 to 10mL of liquid waste.

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