Mercury Instruments AULA 254

Automated Mercury Analyzer for trace levels of mercury in a wide range of samples

• Automated mercury analysis system
• High performance flow analysis technique
• Cold Vapor Atomic Absorption Spectrometry (CVAAS)
• Widest dynamic linear range
• Robust modular construction
• AULAWIN software
• Automated sample digestion module (ASD)
• Gold Trap module for maximum sensitivity
• GoldTrap enhancement for maximum sensitivity of 1 ppt

Mercury Analyzing Applications

The AULA 254 is a completely automated analysis system for determining trace mercury levels in a wide range of samples. The AULA system is designed to be the right tool for researchers and scientists. The instrument automates routine analysis: it tests sample after sample following a specified procedure exactly. This increases efficiency and productivity in your lab.

Applications include:

• Environmental chemistry (mercury in water, mercury in waste water, mercury in effluents, mercury in waste, mercury in sludge, mercury in soil)
• Biological samples (mercury in fish, mercury in blood, mercury in saliva, mercury in hair, mercury in food, mercury in urine)
• Chemical Industry (process mercury monitoring, quality control)
• Geochemistry (geological and mineralogical samples)
• Petro chemistry (mercury in oil products)
• Metallurgy and material testing
• EPA method 245.1, 245.7, 1631, 7470 and 7471A

Proven & Reliable Testing Method

The working principle of the system is based on the continuous flow method. First the mercury contained in the sample is transformed into the elemental state by addition of a reducing agent to the sample
flow. In a cross flow reactor the mercury is stripped with a gas stream and carried into the optical cell which is made entirely of fused silica. There the quantitative determination of mercury is obtained by measuring UV absorption at a wavelength of 253,7 nm at room temperature. This analytical technique is commonly known as cold vapor atomic absorption spectrometry (CVAAS), a method that has proved itself as extremely sensitive and selective over many years.

AULAWIN Mercury Analysis Software

Surprisingly easy to use the AULA-WIN offers all the features of a modern analytical software package. It has been developed with extensive input from our users. Samples, calibration standards and quality control standards (QCS) are entered into the carrousel screen. With an optional barcode sticker sample data can be entered comfortably. A sample table is created automatically and can be viewed in the table screen. Sample dilution factors as well as sample weight and final fill up volume for digestion of solid samples can be entered in the table. The result of the measurement is calculated automatically from the chosen calibration function and displayed in µg/l or µg/kg. The QCS function assures a high level of reliability of the analytical results.

Mercury Data Storage                                                   Autosampler top view

The results of the analyses together with the data necessary for quality assurance (date, time, user ID, sample number, calibration data, instrument parameters) are stored in a file. They are available at any time for display and printout. Worksheet templates can be created and stored to minimize setup time for routine work.

High Productivity for Mercury Analysis

No more purging or rinsing procedures even when samples with high concentrations are analyzed. The typical duration of a full measurement cycle is 80 ... 280 seconds. The quick screening mode allows
performing analyses in even a shorter time.

Mercury Testing Performance

Measurements of up to 20 calibration standards and up to 53 samples and check standards are carried out easily and fully automated. Standards and samples are filled into 10 ml glass vials and positioned
on the autosampler turntable. Reagent solution (for example tin-(II)-chloride) and rinse solution (reagent water) are filled in the corresponding glass tanks. Then the stripping gas flow is adjusted and
measurement is started by a keystroke. The measurement cycle can be interrupted at any time by the operator for selecting any sample to be measured next. Readings and instrument status are displayed in real-time on the screen.

Automatic baseline correction

The stability of the baseline is checked prior to each measurement and the zero point is adjusted automatically. The typical zero drift during a measurement is below 0.0001 absorbance units.

Minimized mercury memory effects

Mercury vapor has a general tendency to absorb on surfaces causing a memory effect. This undesirable property has been minimized by using selected materials (fluoropolymer, borosilicate glass, Tygon LFL) for sample and reagent conducting components and by heating the optical bench. In addition, the autosampler probe and the sample tubing are rinsed after each sample. This also allows a high sample throughput. Even samples with concentrations in the upper measuring range do not produce a carry over to the following sample.

Thermoelectric dehumidifier

Unlike traditional mercury analyzers, which use drying tubes for removing water vapor from the sample gas, the AULA 254 uses a maintenance-free thermoelectric dehumidifier. The dew point of the gas
is decreased below ambient temperature thus the water condenses on the wall of a small glass tube and flows back into the reactor.

Carrier gas flow stabilization with MFC

The stability of the carrier gas flow has a direct effect to the reproducibility of measurements. For this reason the AULA 254 system uses a highly precise (1.5 % accuracy) electronic mass flow controller (MFC).

Safety

The instrument automatically interrupts the measurement if samples with mercury concentrations exceeding the measuring range are detected. In this case the system is immediately cleaned.

Automated sample digestion module (ASD)

The AULA 254 can be equipped with an optional sample preparation system for aqueous samples. The digestion procedure derives from standard methods commonly used in the laboratory. The sample is
automatically drawn from the autosampler vial and is continuously mixed with a strong oxidizing reagent (e.g. potassium permanganate, bromide-bromate). Subsequently the sample/oxidant mixture is heated to ca. 98 C in a heated coil. After the oxidation step hydroxylamine hydrochloride and tin-(II)-chloride are added for reduction of mercury into the elemental state.

The AULA-ASD is economical. Average reagent consumption for 100 analyses is:

• 10 g hydroxylamine hydrochloride
• 1-5 g potassium permanganate
• 20 g tin-(II)-chloride
• 5 L water (deionized)

Achieve detection limits as low as 1 ppt with the included GoldTrap

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AULA 254 Technical Specifications

• Measuring Principal: UV-Absorption, cold vapor technique (CVAAS)
• Wavelength: 253.7 nm
• UV Source: electrodeless low-pressure mercury lamp (EDL)
•  Stabilization method: Reference beam technique
• Optical Cell: Entirely made of fused silica, ca. 230 mm length
• Stripping gas: Argon (optional nitrogen), 4-6 l/h, stabilized with electronic mass flow controller
• Gas-Liquid separator: Bubble-free, non-foaming cross-flow principal design
• Sample gas dehumidifier:  Thermoelectric principle (desiccant free, low surface area)
• Pump: 3-channel peristaltic pump, stabilized fixed speed (AULA-ASD: has two pumps)
• Autosampler: 53-place random access, carousel sampler
• Sample Vials: 10 ml, glass, aluminum foil disc covers AS accessory
• Sample Consumption: ca. 1ml
• Heating coil temp (AULA-ASD) - ca. 98 C
• Detection Limit: <30 pg Hg, with Gold Trap <5pg Hg
• Measuring range: 10 ng/L - 50 ug/L (10 ppt - 50 ppb) with Gold Trap 1 ppt - 5 ppb
• Zero drift: Auto zero before each measurement
• Measuring duration: 60 - 180 seconds typical
• Software: AULA-WIN for Windows based  operating system
• Power supply: 115V or 230 V 50/60 Hz, consumption ca. 100W. with ASD 150W
• Dimensions: Autosampler-reaction unit: 13.6" wide x 11.7" High x 13" deep
• Dimensions: Photometer unit: 6.3" wide x 17.8" High x 14.2" deep
• Weight: 30.8 lbs. without computer