Investigation of the Multielement Capability of Laser-Enhanced Ionization Spectrometry in Flames for Analysis of Trace Elements in Water Solutions

Axner, Ove; Magnusson, Ingemar; Petersson, Julius; Sjöström, Sten

doi:10.1366/0003702874868160

Cited by 52 publications

(7 citation statements)

References 15 publications

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“…*The second step cannot be identified. sensitivities for LEI in flames (3). The sensitivities for flame LEI are given as charge collected per concentration.…”

Section: Resultsmentioning

confidence: 99%

Laser-enhanced ionization spectrometry in a T-furnace

Sjöström¹,

Magnusson²,

Lejon³

et al. 1988

Anal. Chem.

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“…*The second step cannot be identified. sensitivities for LEI in flames (3). The sensitivities for flame LEI are given as charge collected per concentration.…”

Section: Resultsmentioning

confidence: 99%

Laser-enhanced ionization spectrometry in a T-furnace

Sjöström¹,

Magnusson²,

Lejon³

et al. 1988

Anal. Chem.

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“…The outstanding performance of LEI in trace element analysis has been demonstrated in a number of reports previously, both in flames [1,3,4,11,12,19,21,22,28] and in furnaces [-17, 25]. For flame-LEI, detection limits in the 0.001-1 ng/ml range in aqueous solutions are readily obtained with one-step excitations of elements with low or moderate ionization potentials.…”

Section: Detection Limits and Sensitivitiesmentioning

confidence: 93%

“…3 displays 23 elements detected using one-step LEI with the dye Coumarin 153 [19]. Since the atoms primarily are excited to higher states there is a large number of transitions available in LEI.…”

Section: Detection Limits and Sensitivitiesmentioning

confidence: 99%

Analytical applications of laser-enhanced lonization spectrometry in flames and furnaces

1989

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This paper is concerned with a critical analysis of the analytical performance of laser-enhanced ionization (LEI) spectrometry in flames and furnaces as an ultra-sensitive trace-element technique. Updated tables of LEI detection limits, both in flames and furnaces, are given. Special attention is paid to interference phenomena which are unique to the LEI technique. Ways of reducing their influence on the analytical signals are proposed. Finally, advantages and disadvantages of LEI spectrometry as a tool for ultra-sensitive trace element analysis are discussed.Key words: laser-enhanced ionization (LEI), flame, furnace, trace element.Laser-enhanced ionization (LEI) spectrometry is a very powerful technique for detecting low concentrations of metal atoms in solutions I-1-23]. The major characteristics of the technique constitute of a high sensitivity and a rather high resistance to interferences. The general principle of the LEI technique is that an enhancement of the normal ionization processes (collisions) is obtained by optical excitation of the atoms under study by resonant laser light. The enhanced ionization rate is detected as a change in the current passing through a medium (atomic reservoir) exposed to a voltage by means of an electrode arrangement.When a sample is analyzed by LEI, the atomization can, in principle, be done in any of the conventional atomic reservoirs which previously have been developed for standard analytical techniques (absorption or emission techniques). However, LEI has so far most often been done in atmospheric pressure flames (primarily air/acetylene flames) and only recently LEI has been applied to graphite furnaces [8,16,17,[24][25][26].The atoms under study are excited from low lying, highly populated levels (primarily from the ground level) to high lying excited states by resonant laser light. Solution Boxcar Oscilloscope Fig. l. A typical experimental set-up for two-step LEI in flames. C = 10 nF and R = 50 k~This is almost exclusively done by using pulsed dye-laser systems for production of resonant laser light.Since the atomic reservoirs used for LEI are characterized by high temperatures in fairly dense media the collision rates between analyte atoms and buffer molecules are high. Hence, the atoms have certain probabilities of undergoing ionizing collisions. The probability of such collisional ionization is higher the less energy needed for ionization of the (excited) atoms. Therefore, the ionization probability increases the closer to the ionization limit the atoms are being excited [-27].The excitation of atoms in LEI spectrometry can be carried out in several ways. The most common excitation scheme is to excite the atoms from the ground state by absorption of one photon. By using ultra-violet light or by exciting the atoms in two consecutive steps a high ionization rate (efficiency) can be obtained. The two-step excitation is practically done by illuminating the atoms with light from two simultaneously pumped dye lasers, each tuned to a suitable transition wavelength in the...

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“…1988,60,1490. (10) Ryder, John D. Network Lines and Fields, 2nd ed. ; Prentice-Hall: Englewood Cliffs, NJ, 1958; Chapter 6.…”

Section: Literature Citedmentioning

confidence: 99%