The sample gas is fed into an optical cell by a maintenance-free membrane pump. A beam of UV light passes through the optical cell, a part of it is absorbed by the mercury atoms present in the sample.
This method is called “atomic absorption spectroscopy” or shortly AAS. It is extremely selective and sensitive. For mercury determination the AAS method has maintained its importance even if other methods have been worked out since the early beginnings. The AAS method is low in interference and does not require an amalgamation step or expensive carrier gases.
The VM-3000 uses a high-frequency driven electrodeless low pressure mercury lamp as UV source. This lamp emits lines of an extremely narrow bandwidth which are congruent with the absorption lines of the Hg atoms. Cross-sensitivities are thus minimized. The extremely high stability of the UV source in the VM 3000 is a result of the reference beam feedback control method. Total background noise is less than 0.1 µg/m³.
Metal housing with sturdy handle
| Measuring principle: | UV-Absorption |
| Wavelength: | 253,7 nm |
| UV source: | electrodeless low-pressure mercury lamp (EDL) |
| Measuring cell: | fused silica, heated to avoid condensation |
| Stabilization method: | lamp control by reference beam feedback; Auto-zero |
| Measuring ranges: | range I: 0.1 to 100 µg/m³ (0.01-10 ppb) range II: 0 to 1000 µg/m³ range III: 0 to 2000 µg/m³ (0-200 ppb) |
| Sensitivity: | 0.1 µg/m³ (0.01 ppb) |
| Response time (99% signal): |
< 1 second ; continuous operation and real-time reading |
| Alarm: | 3 levels programmable |
| Status alarms: | measuring cell soiled, battery state (option, UV source exhausted |
| Display: | graphical LC display with background illumination |
| Signal outputs: | 4…20 mA; RS 232 for PC or printer ; data logger function (option) |
| Battery option: | external 12 DC source; optional 12 V batteries integrated, ca. 5h capacity |
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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. |
