Design consideration and temperature determination of an automated graphite furnace cup system used for direct sample introduction for ICP optical emission spectrometry

Barnett, Neil W.; Cope, M. J.; Kirkbright, G. F.; Taobi, Abed Alameer H.

doi:10.1016/0584-8547(84)80041-5

Cited by 25 publications

(9 citation statements)

References 6 publications

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“…For example, at a typical observation position of 15 mm HALC and carrier gas flow rate of 0.42 L min 21 , the excitation temperature and electron number density were 5900 K and 3 6 10 13 cm 23 , respectively. Temperature and electron number density dropped to 3700 K and 2 6 10 10 cm 23 , respectively, at a carrier gas flow rate of 1.42 L min 21 . The excitation temperature was reduced by 37% and the electron number density was reduced by 3 orders of magnitude for an approximately 3-fold increase in carrier gas flow rate.…”

Section: Effects Of Carrier Ar Gas Flow Rate On Plasma Excitation Con...mentioning

confidence: 97%

“…In DSI-ICP-AES, analyte appearance time, shape (width and height) of the analyte peak, SBR, and background intensity depend on the position of the sample probe in the ICP discharge. [1][2][3][4][5][6][7][8][9][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Generally, increasing the cup position from a lower position of the ICP (e.g., below the top of the load coil) to a higher position (e.g., above the top of the load coil) gives sharper and more symmetrical analyte emission peaks and, therefore, enhanced SBR. The effects of probe position on plasma excitation conditions, however, are rarely discussed in the literatures.…”

Section: Effect Of Probe Insertion On Plasma Excitation Conditionsmentioning

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: Effects Of Carrier Ar Gas Flow Rate On Plasma Excitation Con...mentioning

confidence: 97%

Section: Effect Of Probe Insertion On Plasma Excitation Conditionsmentioning

confidence: 99%

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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“…The intensity of the continuum spectrum of an ICP is a function of the ICP temperature. 19 Since conductive and radiative heat transfer 20,21 from the sample probe cools the ICP, the reduction in 237 ANALYTICAL SCIENCES FEBRUARY 2000, VOL. 16 background intensity is probably due to a reduction in the plasma temperature.…”

Section: Temporal Profiles Of Zn and Na Emissionmentioning

confidence: 99%

Studies of Matrix Effects for the Analysis of Zinc in Sodium Chloride Using Direct Sample Insertion-Inductively Coupled Plasma Atomic Emission Spectrometry

Chan

Gong

et al. 2000

ANAL. SCI.

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Direct sample insertion (DSI) is an alternative sample introduction technique for the inductively coupled plasma (ICP).A small quantity of the sample is placed in a sample probe and inserted directly into the plasma for vaporization, atomization, excitation and/or ionization. DSI is applicable to solid, powder, as well as liquid samples with 100% sample introduction efficiency. Since the technique was first introduced by Salin and Horlick in 1979, 1 there has been continuous efforts concerning DSI development in the past two decades. 2,3 DSI-ICP is similar to graphite-furnace atomic absorption spectrometry (GF-AAS) in several aspects. Firstly, graphite sample probes are commonly used in DSI-ICP, 3 although tungsten wire loops 4 and metal sample cups 5,6 have also been reported. Secondly, because the sample is thermally evaporated from the graphite probe, the analyte and matrix vaporization behavior and pattern are similar for GF-AAS and DSI-ICP. In addition, analyte vapor is measured in atomic form in a hot and inert atmosphere above the sample probe or in the furnace. DSI-ICP has an advantage that the analyte enters a plasma of higher temperature than the sample probe, while the temperature of the gas atmosphere inside a graphite furnace is usually lower than that of the inside wall of the furnace. Yet, matrix effects in GF-AAS, e.g., vaporization interference and gas-phase reactions, are relevant to DSI-ICP. Vaporization interference is considered to be the major matrix effect for DSI-ICP. 7 The matrix effects on the excitation and ionization characteristics of the ICP are thought to be relatively minor, although suppression in the ICP emission intensity of Cu I, Cd I, Zn I and Pb II in the presence of pyrolysis products of an ion exchange resin has been attributed to changes in the ICP excitation conditions due to matrix effects. 8 It is remarkable that matrix effects on ICP excitation conditions are seldom observed for DSI. The mass flux of the matrix for DSI is much higher than that of solution nebulization. For a sample solution containing 3% NaCl and a typical sample volume of 10 µl, the average mass flux of NaCl introduced into the ICP by DSI is 6×10 -5 g/s if NaCl is completely evaporated in 5 s. The same mass flux for solution nebulization implies a 18% NaCl solution, assuming a 2% nebulization efficiency and a 1 ml/min uptake rate. The introduction of such a high concentration of easily-ionized-element (EIE) into the ICP, if possible, would cause severe matrix effects. [9][10][11][12] In this work, the matrix effects for DSI-ICP on analyte vaporization and on the ICP excitation conditions were studied. A slow insertion rate of the sample probe was used so that a partial separation in time for the vaporization of the test element and the matrix could be obtained. With such a setup, the temporal profile of the ICP emission intensity contained information about both the thermal vaporization and matrix influence of the ICP. Since the uncertainties in the intensity from run to run were eliminated, a direct...

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“…The geometry of the sample probes has a significant effect on the vaporization profile and analytical signal of the analyte. [4][5][6] In general, sample probes having a high heating rate and fast insertion speed are preferred because they lead to larger peak heights and shorter peak widths in the temporal profile. 6 However, the effects of probe insertion on the ICP excitation conditions must also be considered, especially in the presence of matrix effects that shift the appearance time of the analyte.…”

Section: Direct Sample Insertion (Dsi) Is An Alternative Sample Intro...mentioning

confidence: 99%

Effects of analyte appearance time on relative atomic and ionic emission intensities of Zn in direct sample insertion inductively coupled plasma atomic emission spectrometry

Chan

Fan

Chan

2001

J. Anal. At. Spectrom.

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Design consideration and temperature determination of an automated graphite furnace cup system used for direct sample introduction for ICP optical emission spectrometry

Cited by 25 publications

References 6 publications

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

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

Studies of Matrix Effects for the Analysis of Zinc in Sodium Chloride Using Direct Sample Insertion-Inductively Coupled Plasma Atomic Emission Spectrometry

Effects of analyte appearance time on relative atomic and ionic emission intensities of Zn in direct sample insertion inductively coupled plasma atomic emission spectrometry

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