Solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry for the direct determination of traces of boron in biological materials using isotope dilution for calibration

In this work, the possibilities of electrothermal vaporization-inductively coupled plasma mass spectrometry for the direct determination of B in biological samples have been critically evaluated, the goal always being to develop a fast and robust method that could be applied to different samples without significant modi. cations to the working protocol. Four reference materials of different nature (NIST SRM 1570a Trace Elements in Spinach Leaves, NIST SRM 1573a Tomato leaves, NIST SRM 1548a Typical Diet and BCR CRM 281 Rye Grass) were selected for this study. The importance of the use of NH4F center dot HF as chemical modi. er for this element was demonstrated. By using this modi. er, it was observed that the analyte can be vaporized and transported to the ICP in a more efficient way even at low vaporization temperatures (from 1000 degrees C onwards), resulting in a sensitivity increase (of a factor of approximately 10 compared with the vaporization in the absence of any modi. er) while minimizing memory effects and carbon co-vaporization. The temperature program was adapted to permit the effecient use of this modi. er when direct analysis of solid samples was intended. However, although well-defined B signal profiles could be attained also for the solid samples, evidence of signal suppression was observed. Under these conditions, the use of external calibration with aqueous standards would result in underestimated results (40-60% of the expected values). It was demonstrated that the use of isotope dilution can satisfactorily correct for these suppression effects, allowing accurate results to be obtained for all the samples under investigation. The most relevant figures of merit of the method finally developed are: RSD values ranging from 7 to 9%, a detection limit of 8 ng g(-1), a sample throughput of 20 - 25 min per determination and a sample consumption of approximately 5 mg per determination

Electrothermal vaporisation ICP-mass spectrometry (ETV-ICP-MS) for the determination and speciation of trace elements in solid samples : a review of real-life applications from the author's lab

The use of electrothermal vaporisation (ETV) from a graphite furnace as a means of sample introduction in inductively coupled plasma mass spectrometry (ICP-MS) permits the direct analysis of solid samples. A multi-step furnace temperature programme is used to separate the vaporisation of the target element(s) and of the matrix components from one another. Sometimes, a chemical modifier is used to enable a higher thermal pre-treatment temperature, by avoiding premature analyte losses (stabilisation) or promoting the selective volatilisation of matrix components. In almost all instances, accurate results can be obtained via external calibration or single standard addition using an aqueous standard solution. Absolute limits of detection are typically similar to1 pg, which corresponds to 1 ng/g for a typical sample mass of 1 mg. Real-life applications carried out in the author's lab are used to illustrate the utility of this approach. These applications aim at trace element determination in industrial and environmental materials. The industrial materials analysed include different types of plastics - Carilon, polyethylene, poly(ethyl-eneterephtalate) and polyamide - and photo- and thermo-graphic materials. As samples from environmental origin, plant material, animal tissue and sediments were investigated. Some applications aimed at a multi-element determination, while in other, the content of a single, but often challenging, element (e.g., Si or S) had to be measured. ETV-ICP-MS was also used in elemental speciation studies. Separation of Se-containing proteins was accomplished using polyacrylamide gel electrophoresis (PAGE). Subsequent quantification of the Se content in the protein spots was carried out using ETV-ICP-MS. As the volatilisation of methylmercury and inorganic mercury could be separated from one another with respect to time, no chromatographic or electrophoretic separation procedure was required, but ETV-ICP-MS as such sufficed for Hg speciation in fish tissue

Evaluation of the multi-element capabilities of electrothermal vaporization quadrupole-based ICP mass spectrometry

Electrothermal vaporization (ETV) ICP mass spectrometry is a method that combines the ability or the graphite furnace to handle complex samples with the detection power of ICP-MS. It is somewhat Surprising. however, that most works reporting on the application of this method have only described the "simultaneous" (from the same tube firing) determination of 1-3 elements. Different authors have attributed this fact to the limited capability of the quadrupole filter (the most commonly used mass spectrometer ill ICP-MS instrumentation) to deal with the transient signals that electrothermal vaporization produces. Nevertheless, recent works suggest that the real multi-element capabilities of ETV quadrupole-based ICP-MS might have been largely underestimated. A systematic study of the number of mass-to-charge ratios that call be "simultaneously" monitored in ETV quadrupole-based ICP-MS without degrading the precision, the sensitivity and the limits of detection has been carried out. Three elements with different furnace behaviours (Cd, Co and Ti) were chosen for the study. The effect of the dwell time and the way of processing the analytical data were also evaluated. The results indicate that, when using ETV-ICP-MS with it quadrupole-based instrument, no detrimental effects on the precision, detection limits and sensitivity occur its long its it critical value of three or four points to define the signal profile is achieved. This requirement corresponds to the possibility of monitoring more than 20 elements for a standard peak width of 1.5-2 s. Several options for further improvements are also discussed, including the possibility of separating (with respect to time) the vaporization of elements with different furnace behaviours

Electrothermal vaporization for sample introduction in atomic absorption, atomic emission and plasma mass spectrometry : a critical review with focus on solid sampling and slurry analysis

The aim of this work is to review and compare the present possibilities of electrothermal atomic absorption spectrometry (ETAAS), electrothermal vaporization-inductively coupled plasma-optical emission spectrometry (ETV-ICP-OES) and electrothermal vaporization-inductively coupled plasma-mass spectrometry (ETV-ICP-MS) for analysis of solid samples, slurries and complex matrixes. The paper keeps in perspective the historical evolution of these techniques, providing an overview of the most relevant advances in instrumentation, methodology and fundamentals and highlighting the most relevant applications carried out during the last decade. The benefits of continuum source-AAS, the possible impact of diode lasers on this technique, the potential of ETV-ICP-methods for fractionation/speciation studies, as well as for resolving spectral interferences, and the influence of the different types of ICP-MS instrumentation currently available on the overall performance of ETV-ICP-MS will be some of the aspects discussed in more detail

Direct determination of trace amounts of silicon in polyamides by means of solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry

In this work, a method has been developed for the fast and reliable determination of silicon in polyamides (two samples with silicon contents of 10 and 50 mug g(-1) were analyzed) by means of solid sampling electrothermal vaporization ICP-MS. For all silicon isotopes, the occurrence of spectral interferences was studied as a function of the vaporization temperature. The benefits of the use of palladium as a chemical modifier were investigated. Finally, a vaporization temperature of 2400 degreesC, monitoring of Si-29(+) and the addition of 1 mug of palladium were found to be the optimum conditions for the determination. The method finally proposed shows very interesting features for this particular element: the ability to use aqueous standard solutions for calibration, a low sample consumption (a few milligrams only), a high sample throughput (20 min analysis time per sample), a low limit of detection (0.3 mug g(-1)) and a reduced risk of analyte losses and, particularly, of contamination. Additionally, the approach also exhibits multi-element capabilities