Effects of sample probe insertion on plasma conditions in direct sample insertion-inductively coupled plasma-atomic emission spectrometry

Chan, George C.-Y.; Fan, Mau-Nam; Chan, Wing-Shing

doi:10.1016/s0584-8547(00)00284-6

Cited by 7 publications

(12 citation statements)

References 12 publications

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“…2,3 Upon sample probe insertion into the plasma, the background emission intensities reduce significantly [4][5][6] and the plasma excitation temperature (T exc ) and electron number density (n e ) reduce by thousands of degrees and orders of magnitude, respectively. 7,8 In a previous study, 8 we showed that the extent of reduction in plasma excitation conditions due to sample probe insertion mainly depended on the outer diameter of the probe, regardless of the form (solid rod, solid rod with undercut, and hollow cup with undercut) and material (graphite or molybdenum) of the probe. The probe effects (represented by reduction in Zn II/Zn I ratio) increased with probe diameter.…”

Section: Introductionmentioning

confidence: 90%

“…The experimental setup was similar to the one described previously, except for the use of a hollow graphite probe for direct introduction of laser-ablated testing elements into the center of the plasma. 8 The schematic diagram of the experimental setup is shown in Fig. 1.…”

Section: Methodsmentioning

confidence: 99%

“…The inner tube of the torch was enlarged to 9.0 mm to accommodate the sample probe. 8 A He gas stream was used to prevent arcing between the plasma and the graphite sample probe during probe insertion.…”

Section: Dsi-icp-aesmentioning

confidence: 99%

“…The use of a hollow probe also circumvents the need for a separate capillary and relatively high carrier gas flow rate (1 L min 21 ) for testing element introduction that was used in a previous study. 8…”

Section: Introductionmentioning

confidence: 99%

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Novel setup for investigation of the plasma conditions in direct sample insertion inductively coupled plasma atomic emission spectrometry (DSI-ICP-AES)

Cheung

Chan

2004

J. Anal. At. Spectrom.

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Insertion of a sample probe into the inductively coupled plasma (ICP) for direct sample insertion (DSI) could change the plasma excitation conditions. In this study, a novel setup is proposed for the investigation of the probe effects. A hollow graphite tube was used as a stand-in for the DSI sample probe to exert probe effects on the plasma. Laser-ablated testing elements (Fe, Zn and Mg) were introduced separately into the central channel of the plasma via the hollow graphite tube for measurement of plasma excitation temperature and electron number density. A relatively low Ar carrier gas flow rate (0.42 L min 21 ) was used to minimize perturbation to the plasma due to the gas flow. The study shows that the extent of reduction in plasma excitation temperature and electron number density increases with probe insertion position at all observation heights. In addition, the probe effects strongly depend on the relative distance of the observation position to the tip of the probe. The probe effects are the strongest near the tip of the probe and reduce at observation positions further away from the tip. Signal-to-background ratios (SBR) of the testing elements also depend strongly on the probe insertion position and the relative distance of the observation position to the tip of the probe. The SBR peaks at 5-10 mm above the tip of the sample probe. The vertical profile of SBR depends on analyte diffusion in the plasma and the plasma excitation conditions.

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Section: Introductionmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Dsi-icp-aesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Novel setup for investigation of the plasma conditions in direct sample insertion inductively coupled plasma atomic emission spectrometry (DSI-ICP-AES)

Cheung

Chan

2004

J. Anal. At. Spectrom.

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“…Because of these practical limitations, direct introduction of powders into the ICP-OES has not been exploited successfully to its full potential for routine analysis in spite of its many important advantages. 8,9 Laser ablation (LA) is increasing in popularity as a method of direct solid sample introduction. In particular, LA coupled with ICP-MS has become a well-established, powerful, rapid, and sensitive method for analysing trace elements without extensive sample preparation.…”

Section: Introductionmentioning

confidence: 99%