Reduction of matrix ionization interference in laser-enhanced ionization spectrometry

Turk, Gregory C.

doi:10.1021/ac00231a011

Cited by 83 publications

(49 citation statements)

References 10 publications

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“…The LEI spectrometer utilizes a water-cooled cathode imm ersed in the¯ame atom izer. 9 The laser excitation system ( Fig. 1) consists of either a single dye laser (S canM ate 1, L am bd a P hy sik, F t. L au derdale, F L ) pumped by the third harm onic (355 nm) of a Nd:YAG (Surelite II-10, Continuum, Santa Clara, CA) operating at 10 Hz, or two dye lasers (ScanMate 2 and FL 3001, Lambda Physik) pumped by a XeF excimer laser at 351 nm (L PX 210i, Lambda Physik) operating at 30 Hz.…”

Section: Exp Erim Entalmentioning

confidence: 99%

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O₂/Acetylene Flames

et al. 1999

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Laser-enhanced ionization (LEI) measurements of As, Se, Sb, and Cu in air/acetylene and Ar/O2/acetylene flames are reported. The use of far-UV excitation wavelengths to perform one- and two-step LEI excitation from the ground states of As, Se, and Sb is reported for the first time. Significant ionization background signals are observed for far-UV excitations in the air/acetylene flame, but are reduced by substituting an (80:20) Ar/O2 mixture for air as the flame oxidant. The sensitivities of the individual LEI techniques are also increased by the Ar/O2 gas substitution. The limits of detection for As, Se, Sb, and Cu are 30, 0.5, 9 and 2 ng/mL, respectively, and compare favorably with previous LEI reports. Due to the poor atomization characteristics of As and Se, the utility of hydride generation (HG) sample introduction with LEI detection has been explored. Although high sensitivity has been observed for the HG-LEI approach, limits of detection were not evaluated due to nonlinear responses of the signals with respect to analyte concentration.

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Section: Exp Erim Entalmentioning

confidence: 99%

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O₂/Acetylene Flames

et al. 1999

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“…Flame Burner. The experimental apparatus of a twostep LEI has been illustrated previously, 11,15,16,26 so only a brief description is given below. We performed the LEI experiment, as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The resulting LEI ions were collected with a water-cooled cylinder probe along the ¯ame, biased at 2 1000 V and suspended 1.5± 2.0 cm above the burner head. 16 In an effort to avoid interference from ¯ame components, the electrode was positioned slightly outside the ¯ame, about 4± 6 mm off the axis of the burner slot. The ion enhancement in this work proved to be comparable to that obtained with the electrode inside the ¯ame.…”

Section: Methodsmentioning

confidence: 99%

Spatially Resolved Temperature Determination of an Air/Acetylene Flame Using the Two-Step Laser-Enhanced Ionization Technique

Lin

1998

Appl Spectrosc

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We have demonstrated a two-step laser-enhanced ionization (LEI) technique to be potentially useful in measuring a spatially resolved temperature in an atmospheric air/acetylene flame. As a complement to the existing optical methods, LEI detection shares the advantages of extremely high sensitivity and the capability of achieving a high spatial resolution, confined to the dual-beam intersection area of 1 mm × 1 mm. A theoretical model was developed to precisely extract the temperature information from the obtained two-step LEI signal. The physical parameters required in the experiment include simply the relative values of the LEI signals, associated with the fine-structure doublets of a selected thermometric species, and their corresponding laser energies. The subsequent treatment is also convenient without the need to know the absolute energy of the incident laser beam and to accurately calibrate the detection system. Al and Ga were selected as the thermometric species. The resultant radial and axial temperature mappings are consistent with each other and are also comparable with those reported by other optical methods.

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“…A wa ter-cooled cyl in der probe along the flame axis was bi ased at -1000 V and sus pended 2 cm above the burn head. 30 The burner served as the other elec trode, from which the LEI cur rent sig nal was col lected and am pli fied with a cur rent-tovoltage con verter (Keithley, Model 428), and then fed into a tran sient dig i tizer (LeCory 9450A). The LEI wave form was av er aged over 200 pulses and trans ferred to a PC through a GPIB in ter face board.…”

Section: Lei De Tec Tionmentioning

confidence: 99%

Application of Laser‐Enhanced Ionization Spectroscopy: Effect of Dissociation Constant on the Atomization Efficiency Determination in an Acetylene‐Air Flame

Lin

2001

J Chinese Chemical Soc

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By using laser‐enhanced ionization (LEI) technique, we have studied atomization efficiencies of the alkalihalides in an acetylene/air flame. As an aqueous solution of the metal salt was nebulized into the burner head, a flame with a high temperature of about 2500 K may cause dissociation of the ionic bond to release the free metal atoms. The ratio of the number density of free metal atoms present in the flame to the total number density of the same metal element nebulized determines the atomization efficiency. In this work, binary salt solutions including LiX, NaX, and KX (X=Cl, Br, and I) were used; each was prepared at 5 ppm (μg/mL) metal concentration. The atomization efficiency of the metal element was measured, as the accompanied halogen species was varied. We found that the ratios of atomization efficiencies of the akalielement in different halide compounds were almost equal to one. Atomization efficiency determination is dominated by the metal atom, but weakly influenced by the binding halogen species. The observation may be interpreted satisfactorily by using the Sugden‐Bulewicz model. Based on this model, the metal atomization efficiency for different halide compounds depends on the number densities of the halogen atoms and the related dissociation constants. For the binary salt with a small concentration and a large dissociation constant, the atomization efficiency determination tends to be dominated by the metal atom alone.

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Reduction of matrix ionization interference in laser-enhanced ionization spectrometry

Cited by 83 publications

References 10 publications

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O₂/Acetylene Flames

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O₂/Acetylene Flames

Spatially Resolved Temperature Determination of an Air/Acetylene Flame Using the Two-Step Laser-Enhanced Ionization Technique

Application of Laser‐Enhanced Ionization Spectroscopy: Effect of Dissociation Constant on the Atomization Efficiency Determination in an Acetylene‐Air Flame

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Reduction of matrix ionization interference in laser-enhanced ionization spectrometry

Cited by 83 publications

References 10 publications

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O2/Acetylene Flames

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O2/Acetylene Flames

Spatially Resolved Temperature Determination of an Air/Acetylene Flame Using the Two-Step Laser-Enhanced Ionization Technique

Application of Laser‐Enhanced Ionization Spectroscopy: Effect of Dissociation Constant on the Atomization Efficiency Determination in an Acetylene‐Air Flame

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Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O₂/Acetylene Flames

Far-Ultraviolet Excited Laser-Enhanced Ionization Spectrometry of As, Se, Cu, and Sb in Air/Acetylene and Ar/O₂/Acetylene Flames