Description

- High selectivity of analysis based on the ZAAS-HFM technique
- Totally automated operation and adjustment for a specific element
- Compact benchtop design incorporating all spectrometer, atomizer, graphite furnace, light sources, detector, and power supply components into a single unit
- Fast 62.5-mm focal length monochromator with a 1800-l/mm grating covering the 190 - 800 - mm spectral range
- Built-in autosampler for 55 samples
- Electrothermal atomization in a Massman graphite furnace
- Computer-controlled automated six-lamp turret.

The MGA-915 AA spectrometer employs a scheme for high-frequency modulation of light polarization with transverse magnetic field allowing a higher modulation frequency, up to 50 kHz. This is the most efficient up-to-date means for the correction for nonselective background absorption. Thus, even such complex organic samples as milk, juices, and blood can be assayed without preliminary mineralization, the requirements for the full mineralization of more complex samples, such as food products, soil, etc., being made much more lenient as well, because the sample weight can be drastically decreased due to the high sensitivity of the instrument. In addition, this technique provides for a threefold decrease in power consumption and for shortening the warm-up time to 10 minutes.

*For samples of 40 µl volume; the sample volume being increased to 200 µl, the detection limit improves 5-fold
**Air pumping time being 5 min

Sample handling
Multiple sample input with intermediate drying is provided to lower detection limit when assaying natural, drinking, and industrial water. The instrument can be furnished with an air sampler, whereby metal airborne aerosols are electrostatically precipitated from the air directly onto separable graphite atomizers. The MGA-915 spectrometer affords concurrent continuous on-site assaying of 6 to 8 selected elements in the air.

Automated measuring procedure
Switching from one element to another is controlled by a computer. The necessary light source is set using a turret with 6 hollow-cathode lamps. The monochromator is automatically tuned to a wavelength corresponding to the specific element, and the atomization parameters drying and atomization (temperature and duration, and consumption of argon) are set according to the stored library data. An analysis is carried out automatically, including drying, pyrolysis, and atomization of a sample and purification of the cell. The analysis procedure and its results are displayed on the screen of a computer monitor. The dedicated software is MS WindowsR compatible system, enabling easy-to-grasp monitoring of the operation procedures and assay results.

Simple maintenance and service
The cooling water circulates in a closed loop, no tapping to external water supply being needed. The service life of a Massman graphite atomizer with pyrocoating commonly amounts to about 150 assays, and to 300 assays when operating with readily volatile elements (Cd, Pb, Zn).