ETV-ICP-AES

With solid sampling-electrothermal vaporization-inductively coupled atomic emission spectrometry (SS-ETV-ICP-AES), Cu in two environmental CRMs was determined using a third CRM with similar matrix as calibrant. Comparison with a reference solution showed good agreement (Verrept et al. 1993). 

ScHRON W, Liebmann A, Nimmereall G 2000) Direct solid sample analysis of sediment, soils, rocks and advanced ceramics by ETV-ICP-AES and GF-AAS. Fresenius J Anal Chem 366 79-88. 

ETV-ICP-AES can be used to determine sulfur catalyst residues in bisphenol-A a drawback is serious contamination of the graphite [206]. 

ELEMENT CONTENTS DETERMINED IN TWO TANTALUM SAMPLES USING SOLID SAMPLING ETV-ICP-AES IN COMPARISON WITH THE RESULTS OBTAINED BY SOLID SAMPLING ETA-AAS... 

LIMITS OF DETECTION OF AN ETV-ICP-AES METHOD FOR THE ANALYSIS OF TANTALUM POWDERS AS COMPARED TO SOLUTION ICP-AES USING NEBULIZATION (Sol-ICP-AES) AND SOLUTION ETA-AAS (Sol-ETA-AAS) ... 

ETV-ICP-AES, and ETV-ICP-MS. It includes three detailed GEAAS solid sampling chapters by Kurfiirst (1998b, c, d), a chapter by Stoeppler and Kurfiirst (1998) on introduction of slurry samples into the graphite furnace, and a chapter by Verrept et al. (1998) on solid sampling by electrothermal vapori-zation-inductively coupled plasma-atomic emission and mass-spectrometry (ETV-ICP-AES/-MS). A number of authoritative, in-depth chapters have been published. 

ETV electrothermal vaporization (as a method of sample introduction) ETV-ICP-AES electrothermal vaporization-inductively coupled plasma atomic emission ETV-ICP-MS electrothermal vaporization-inductively coupled plasma mass spectrometry... 

G. Zaray, F. Leis, T. Kantor, J. Hassler, and G. Tolg, Analysis of silicon carbide powder by ETV-ICP-AES, Fres. J. Anal. Chem. 1993, 346, 1042-1046. 

Another improvement that will allow quick simultaneous oligoelement homogeneity determinations in milligram samples can be expected by the use of solid sampling ETV-ICP-MS/AES and laser ablation ICP-MS which are now being studied in detail (Moens et al. 1995 Schiffer and Krivan 1999 Dobney et al. 2000). 

In ICP-AES and ICP-MS, sample mineralisation is the Achilles heel. Sample introduction systems for ICP-AES are numerous gas-phase introduction, pneumatic nebulisation (PN), direct-injection nebulisation (DIN), thermal spray, ultrasonic nebulisation (USN), electrothermal vaporisation (ETV) (furnace, cup, filament), hydride generation, electroerosion, laser ablation and direct sample insertion. Atomisation is an essential process in many fields where a dispersion of liquid particles in a gas is required. Pneumatic nebulisation is most commonly used in conjunction with a spray chamber that serves as a droplet separator, allowing droplets with average diameters of typically <10 xm to pass and enter the ICP. Spray chambers, which reduce solvent load and deal with coarse aerosols, should be as small as possible (micro-nebulisation [177]). Direct injection in the plasma torch is feasible [178]. Ultrasonic atomisers are designed to specifically operate from a vibrational energy source [179]. 

Application to solid polymer/additive formulations is restricted, for obvious reasons. SS-ETV-ICP-MS (cup-in-tube) has been used for the simultaneous determination of four elements (Co, Mn, P and Ti) with very different furnace characteristics in mg-size PET samples [413]. The results were compared to ICP-AES (after sample dissolution) and XRF. Table 8.66 shows the very good agreement between the various analytical approaches. The advantage of directly introducing the solid sample in an ETV device is also clearly shown by the fact that the detection limit is even better than that reported for ICP-HRMS. The technique also enables speciation of Sb in PET, and the determination of various sulfur species in aramide fibres. ETV offers some advantages over the well-established specific sulfur analysers very low sample consumption the possibility of using an aqueous standard for calibration and the flexibility to carry out the determination of other analytes. The method cannot be considered as very economic. 

A. Alimonti, F. Petmcci, C. Dominici, S. Caroli, Determination of Pt in biological samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) with electrothermal vaporization (ETV), J. Trace Elem. Electrolytes Health Dis., 1 (1987), 79D83. 

Fig. 8.3. (A) Scheme of a graphite-ETV modified for ICP-AES work (1) graphite tube, (2) graphite platform, (3) electrical contacts, (4) cooling water chambers, (5) protecting gas chambers, (6) automatic shutter, (7) ETV-ICP connecting interface. (B)Two different ETV-ICP connecting interfaces (b.l) Nozzle-type aluminium-made interface with cooling bypass gas admittance (b.2) same as b.l but with a larger inner diameter prior to the bypass gas entrance. (Reproduced with permission of the American Chemical Society.)...

Introducing samples to the plasma via liquids reduces sensitivity because the concentration of the analyte is limited to the volume of solvent that the plasma can tolerate. An electro-thermal method seems an obvious choice to increase the detection limit as it will vaporise entirely most neat samples or using an increased concentration of sample in a suitable solvent. The sample is placed on a suitable open graphite rod in an enclosed compartment and heated rapidly (Figure 2.15). The electronics required for ICP-OES-ETV (inductively coupled plasma-optical emission spectroscopy-electro-thermal volatilisation) is similar to that for A AS and detection limits are better than ICP-AES. 

Sequential extraction yielding watersoluble and non-soluble fractions 2-dimensional chromatography (SEC on Superdex 75 HiLoad 16/60 column and AE on Dionex AS 10 column with gradient elution, pH 8) and on-line UV-ICP-MS (280 nm, Se,82Se) SDS-PAGE-ETV-ICP-MS... 

EAAS and ICP-AES (Ihnat 1984). Klock-enkamper (1997) has a plot of absolute TXRF DLs for residues of aqueous solutions versus element atomic number, under various experimental conditions, and an instructive graphical presentation of actual TXRF detection limits for real samples after specific preparations. Tblgyessy and Klehr (1987) compare detection limits of some analytical methods, including classical methods, AAS, LAS, polarography, mass spectrometry, NAA, and isotope dilution analysis, and include more detailed DL information for NAA techniques. A nice comparison of DLs (in pg) for NAA, ETV-ICP, GF-AAS and ETV-ICP-MS is tabulated by Dybczynski (2001). Naturally, a wealth of information is available in handbooks, an example of which is the one by Robinson (1974) containing detailed listings for various spectroscopic methods. 

The requirements for ETV-ICP systems (both ICP-AES and ICP-MS) differ significantly from those for ETA-AAS. When using ETV-ICP, it is necessary to introduce a volatile sample into the gas stream. The atomization stage is then performed in the ICP unit. This is the reason why the technique is referred to as ETV in the case of ICP-AES and ICP-MS, but ETA (electrothermal atomization) in the case of AAS. The chemical matrix effects observed in AAS are negligible using ETV-ICP, whereas the transport efficiency of the sample from the ETV unit to the ICP unit is critical to the analytical performance in ETV-ICP-MS. 

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