AULA 254

The AULA 254 is used for fully automatic determination of mercury traces in liquid samples and sample digests. The instrument carries out routine analysis: sample after sample following exactly the preselected procedure thus increasing efficiency and productivity of your lab.

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.

No long 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.


Measurements of up to 20 calibration standards and up to 53 samples and check standards are carried out fully automatically. Standards and samples are filled into 10 ml glass vials and positioned on the auto-sampler 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.


Measuring principle: UV-Absorption, cold vapor technique (CVAAS)
Analytical wavelength: 253,7 nm
UV source: Electrodeless low-pressure mercury discharge lamp
Stabilization method: Reference beam technique
Optical cell: Entirely made of fused silica, ca. 230 mm length
Optical cell heating: Approx. 50° C
Stripping gas: argon (optional nitrogen), 4-6 l/h,stabilized with electronic mass flow controller
Autosampler: 53 place random access, turntable-type
Sample vials: 10 ml, glass; aluminium foil disc covers as accessory
Heating coil temperature: ca. 98° C
Detection limit: < 80 pg Hg
Measuring range: 10 ng/l … 50 µg/l (GoldTrap off); 1 ng/l … 5 µg/l (GoldTrap on)
Zero drift: Auto zero before each measurement
Measuring duration: Typical 60 – 280 seconds
Software: AULA-WIN, Windows®based
Electrical power supply: 115 V / 230 V~; 50 – 60 Hz, consumption ca. 100 W
(AULA 254-ASD: 120 W)
Dimensions: approx. 37 x 38 x 44 cm (WxHxD)
Bench space requirements: 50 x 70 cm (W x D), excl. PC
Weight: Approx. 14 kg total (excl. PC)
Mercury Instruments As a leading supplier of high precision analytical equipment, we strive at all times to offer top quality solutions. Our products are manufactured according to the ISO 9001 quality regulations.


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