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Zeeman-effect background correction has become commonplace in graphite furnace AAS. While providing a few unique capabilities, Zeeman-effect background correction typically suffers signal rollover, as well as diminished sensitivity and accuracy versus deuterium background correction.
Today GBC's Avanta Ultra Z introduces technical breakthroughs which revolutionize graphite furnace performance.
The major breakthrough is the unique Variable Magnetic Field Strength. The magnetic field strength may be set as a method parameter, with values between 0.6 and 1.1 Tesla. The Avanta Ultra Z is the only Zeeman-effect graphite furnace system which allows the user to set the magnetic field strength for a method or application.
The benefits of this innovative feature can truly be measured only by key performance indicators for Zeeman-effect graphite furnace:
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Sensitivity as measured by characteristic mass.
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Detection limits
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Calibration linearity and reduced roll-over.
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Characteristic Mass
The characteristic mass describes the sensitivity as the amount of analyte required to produce an absorbance of 0.0044. The lower the characteristic mass value the better the sensitivity.
The magnetic field strength can be manipulated to optimize the sensitivity for each element. This unique feature of the Avanta Ultra Z is unrivalled. Competitive technologies, both new and old, cannot achieve this level of performance since their field strength is typically a fixed field strength.
Detection Limits
All things being equal, improved sensitivity should lead to improved detection limits. Detection limits for some of the more important elements are shown in Table 1.
| Element |
l (nm) |
Ultra Z (pg) |
| Tl |
276.8 |
6.0 |
| Pb |
217.0 |
<1.0 |
| Cu |
324.8 |
<1.0 |
| Au |
242.8 |
<1.0 |
Table 1. 3 sigma detection limit data for the Avanta Ultra Z.
Calibration Linearity
Good calibration linearity is one important factor in achieving the greatest dynamic working range at high concentration, accuracy of analysis and reduction in the number of over-range samples to be re-analyzed. The magnetic field strength parameter can also be optimized to provide more linear calibration curves.
Thallium is a particularly difficult element to analyze using the Zeeman background correction technique. By optimizing the magnetic field strength the Avanta Ultra Z is able to extend the dynamic range at least 30% further than other Zeeman technologies.
Copper is another element that exhibits poor calibration linearity in Zeeman graphite furnace. As the magnetic field is increased to 1.0 Tesla, the sensitivity is greatly increased and the calibration working range is extended by at least 30%.
These are just a few of the benefits offered by the performance enhancements of the Avanta Ultra Z.
With increased sensitivity, the response to analyte concentration/mass is greater in the normal working range resulting in improved calibration linearity. Furthermore, the concentration at which roll-over occurs is higher because of the optimized Zeeman-effect achieved with the Avanta Ultra Z. Overall, this leads to an extended dynamic range when compared to other Zeeman-effect systems.
In the development of this product, GBC Scientific Equipment focused on key performance indicators of graphite furnace AAS-sensitivity, detection limits, linear dynamic range and operational costs. The incorporation of a workhead which delivers a high magnetic field with variable field strength was essential to meet these criteria and surpass the performance of existing technologies.
The Avanta Ultra Z offers the greatest dynamic range and best detection limits of any Zeeman-effect Atomic Absorption Spectrometer. For further information, contact us.
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