Detection of titanium in electrothermal atomizers by laser-induced fluorescence : Part 1. Determination of optimum excitation and detection wavelengths

• A detailed investigation has been performed of suitable excitation and detection wavelengths of Ti for the technique of laser-induced fluorescence in electrothermal atomizers. Fluorescence spectra (most often in the 250-350 nm region) from the 39 excitation wavelengths conjectured to be the most important (in the 220-270 nm region) have been investigated in more detail by the use of an intensified CCD detector. The fluorescence spectra were found to have a rich occurrence of peaks (about 50 each), of which many cannot be found in existing atomic wavelength data in the literature. All of the peaks found (with one exception) could be identified thanks to a home-made program that calculates atomic wavelengths from existing energy level data. Most of the spectra are dominated by ''indirect'' transitions (i.e. fluorescence from an upper level that is different from the one accessed by the laser) despite the prediction of existing ''direct'' transitions. This indicates that the collisional redistribution processes amongst the excited levels, in general, are faster than typical fluorescence rates for Ti in graphite furnaces. Suitable excitation and detection wavelength combinations are given. One such suitable choice is excitation at 264.662 nm since the fluorescence following this excitation consisted of peaks of almost equal magnitude in three different wavelength regions (around 295, 319 and 338 nm).

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

laser-induced fluorescence

electrothermal atomizers

graphite furnace

LIF-GF

intensified charge coupled device

Ti

trace element analysis

charge-coupled-device

absorption spectrometry

tube atomization

trace amounts

resonance

thallium

lead

antimony

flames

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)