Chemical equipment: Flame Atomic Absorption Spectroscopy (SpectrAA 220 Fast Sequential)

Flame Atomic Absorption Spectroscopy
(SpectrAA 220 Fast Sequential)

Description:
FAAS (Flame Atomic Absorption Spectroscopy) is a fast and easy technique with an extremely high sensitivity (especially for elements like Pb, Cd, Cu and Cr), although problems can arise as a result of chemical (a much worse situation than with ICP-AES) and spectral interferences.
The sample is atomised in the flame, through wich radiation of a chosen wavelength (using a hollow cathode lamp) is sent. The amount of absorbed radiation is a quantitative measure for the concentration of the element to be analysed. The most courant gas mixtures used are air/acetylene and nitrous-oxide/acetylene. The latter resulting in higher atomisation efficiencies and thus better detection limits for elements like Si, Al, Sc, Ti, V and Zr. The air/acetylene flame can be used for easy atomisable elements (e.g. As and Se). Background correction can be achieved with a deuterium lamp although several disadvantages subsequently occur.
A disadvantage of the AAS technique is the non linearity of the calibration curves when absorbance become higher than 0.5 to 1. The relative standard deviations are between 0.3 and 1% for absorbances of 0.1 to 0.2. Detection limits for flame AAS vary enormeously: from 1 - 5 ppb (e.g. Ca, Cd, Cr, Cu) to more than 1000 ppb (e.g. P). Some elements (e.g. B, C, Br) cannot be measured at all.
The SpectrAA-220 FS measures samples element by element, unlike conventional AA systems which still determine all samples for one element, before repeating these samples again for subsequent elements.

Technical details:
SpectrAA-220 FS Fully automated PC-controlled double beam atomic absorption spectrometer with fast sequential operation for improved productivity. Fitted with 4 lamp positions and automatic lamp selection.
Wavelength range 185 - 900 nm
Optics Narrow beam optics matches flame and furnace profiles. Optics are fully sealed and mirrors quartz overcoated. Rotating beam combiner alternatively passes sample beam or reference beam into the monochromator for maximum light transmission.
Optical bench Optics mounted on a flat plate with three dimensional cover for protection from dust and vapour.
Slits Automated slit selection
Grating Holographic diffraction grating with 1200 lines/mm blazed at 240 nm.
Monochromator Automated 0.25 metre Czerny-Tuner monochromator with computer controlled wavelength selection and peaking.
Photomultiplier Selected wide range R 446 photomultiplier covering full wavelength range.
Background corrector High intensity deuterium background corrector. Range 185 -425 nm to 2.3 Abs. 2 ms response. Electronic modulation with automatic attenuation. Easily alligned and replaced by the user.
Lamps 4 lamp positions. All lamps operated simultaneously in fast sequential mode.
Spray chamber Fluorinated high density polyethylene Mark 7 design for aqueous and organic solutions.
Burner Incoloy air/acetylene burner with teflon corrosion shield. Provides external burner rotation. Nitrous-oxide/acetylene burner.
Impact bead Externally adjustable glass impact bead. Optional teflon bead for use with HF application.
Nebulizer Adjustable nebulizer with inert platinum/iridium capillary and PEEK venturi for corrosion resistance.

Room: 01.53

More Technical information: Techinfo@mtm.kuleuven.be

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Last modified: January, the 18^rd, 2002


Technical details:
SpectrAA-220 FS	Fully automated PC-controlled double beam atomic absorption spectrometer with fast sequential operation for improved productivity. Fitted with 4 lamp positions and automatic lamp selection.
Wavelength range	185 - 900 nm
Optics	Narrow beam optics matches flame and furnace profiles. Optics are fully sealed and mirrors quartz overcoated. Rotating beam combiner alternatively passes sample beam or reference beam into the monochromator for maximum light transmission.
Optical bench	Optics mounted on a flat plate with three dimensional cover for protection from dust and vapour.
Slits	Automated slit selection
Grating	Holographic diffraction grating with 1200 lines/mm blazed at 240 nm.
Monochromator	Automated 0.25 metre Czerny-Tuner monochromator with computer controlled wavelength selection and peaking.
Photomultiplier	Selected wide range R 446 photomultiplier covering full wavelength range.
Background corrector	High intensity deuterium background corrector. Range 185 -425 nm to 2.3 Abs. 2 ms response. Electronic modulation with automatic attenuation. Easily alligned and replaced by the user.
Lamps	4 lamp positions. All lamps operated simultaneously in fast sequential mode.
Spray chamber	Fluorinated high density polyethylene Mark 7 design for aqueous and organic solutions.
Burner	Incoloy air/acetylene burner with teflon corrosion shield. Provides external burner rotation. Nitrous-oxide/acetylene burner.
Impact bead	Externally adjustable glass impact bead. Optional teflon bead for use with HF application.
Nebulizer	Adjustable nebulizer with inert platinum/iridium capillary and PEEK venturi for corrosion resistance.