Direct Analysis by Thermal Decomposition
The Teledyne Leeman Labs Hydra IIC is a fully automated analyzer that measures mercury in solid, semi-solid, liquid, and air sample matrices directly without any acid digestion. It offers many benefits including:
How the Hydra IIC Mercury Analyzer Works
The Hydra IIC combustion atomic absorption (CAA) mercury analyzer is an independent, stand-alone analyzer that uses atomic absorbance (AA) spectroscopy to obtain reliable quantitative data from simple to complex sample matrices. By using direct combustion combined with a proprietary catalyst, interfering compounds such as sulfur and nitrogen oxides are removed. The combustion process entails a continuous linear flow of carrier gas through the entire system, including both the decomposition and catalyst furnaces. Figure 2 shows the system components and processes of the Hydra IIC CAA mercury analyzer.
Figure 2: Principle of Operation
First a weighed sample (1) is introduced to a decomposition furnace (2) with oxygen (or air) flowing over the sample. The furnace temperature is then raised in two stages to first dry the sample, then to combust or decompose the sample. The gases resulting from the decomposition are carried through a catalyst furnace to remove halogens, nitrogen oxides, and sulfur oxides (3). The remaining combustion products, including elemental mercury (Hg0), are swept through a Nafion® dryer (4) and then to a gold trap (5) that captures the mercury while letting the other gases pass through. The gold trap is then heated to release the Hg0 into a carrier gas which transports it to the spectrometer (6). In the spectrometer, the gas is directed through two 5” high sensitivity (for low concentrations) optical cells, and then one 1” low-sensitivity (for high concentrations) optical cell. The light from the Hg lamp travels through the cells using a system of reflective mirrors. The transient signal is measured by the Atomic Absorption Detector (7). Waste gases exiting the system are chemically scrubbed with an activated carbon mercury trap or exhausted out of the lab at the end of the process.
The two peaks are integrated and reported against the best calibration of the two cells available. The use of two cells provides the best detection limit with a wider dynamic range than a detection limit provided by a single optical cell path length.
Figure 3: Calibration Standards Peak Profiles
Is CAA the Right Technique for Your Lab?
Selecting the right mercury analysis technique ultimately depends on your specific analytical needs. Answering a few simple questions could determine if CAA is right for your mercury determinations. Does your laboratory follow EPA 7473 or is your laboratory not bound by a regulatory method? Do you prefer not to digest samples? Are your samples mostly solid matrixes? If you answered yes, then the Teledyne Leeman Labs Hydra IIC will meet your needs and will be a sound, long-lasting investment.
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