Martín Resano

Direct solid sampling with electrothermal vaporization/atomization: what for and how?

In this article, the advantages and the disadvantages of solid sampling-graphite-furnace-based methods are critically examined, taking into account the latest research. A discussion of the different situations for which these methods are best suited within analytical chemistry is presented, together with a general methodology intended to maximize their advantages. The topics discussed include achieving a selective atomization/vaporization of the analyte, calibration, the use of alternative working conditions, and data treatment as a function of the specific goals of the analysis. The purpose of the article is to offer a critical, but tutorial, evaluation of the possibilities of these methods, making it easier for new users to approach them and take advantage of their possibilities.

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.

Inductively coupled plasma – Tandem mass spectrometry (ICP-MS/MS): A powerful and universal tool for the interference-free determination of (ultra)trace elements – A tutorial review

This paper is intended as a tutorial review on the use of inductively coupled plasma - tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H2, O2 and NH3, also the use of promising alternative gases, such as CH3F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis.

Laser ablation‐inductively coupled plasma mass spectrometry in archaeometric research

Laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is a solid sampling technique in continuous expansion in all types of research fields in which direct multi-elemental or isotopic analysis is required. In particular, this technique shows unique characteristics that made its use recommended in many archaeometric applications, where valuable solid artifacts are often the target samples, because it offers flexibility to achieve spatially resolved information with high detection power and a wide linear range, in a fast and straightforward way, and with minimal sample damage. The current review provides a systematic survey of publications that reported the use of LA-ICPMS in an archaeological context, highlights its main capabilities and limitations and discusses the most relevant parameters that influence the performance of this technique for this type of application.

Theoretical evaluation of solid sampling-electrothermal atomic absorption spectrometry for screening purposes

Obtaining results in the determination of metals by electrothermal atomic absorption spectrometry is conditioned by the non-homogeneity of the sample and the possible appearance of outliers, which make it difficult to obtain reliable results with only a few measurements. In order to establish the optimum conditions for using the technique as a screening method, 18 000 results corresponding to different possible situations were simulated by computer and subsequently analysed using information theory. In view of the results obtained, it can generally be claimed that the median can be used to better effect than the mean value as the former is less affected by the potential presence of outliers. Using the median and with normal working conditions, the minimum number of measurements that need to be carried out to guarantee a recall of over 0.95 in a screening method ranges from 5 to 20, involving between 15 min and 1 h work.

Accurate determination of S in organic matrices using isotope dilution ICP-MS/MS

Accurate determination of low levels of S in organic matrices by means of isotope dilution ICP-single quadrupole MS (e.g., for quantification of S components in reverse phase HPLC-ICP-MS experiments) is often not feasible. This work describes an accurate, sensitive and fast analytical method for the determination of S in organic matrices by means of a recently developed ‘triple quadrupole’ ICP-MS instrument, operated in MS/MS mode. The added value of the MS/MS approach for this application has been clearly visualised by varying the width of the bandpass of the first quadrupole analyzer from “fully open” (standard mode) down to single mass width (MS/MS mode). As a proof-of-concept, a biodiesel reference material has been analysed for its S content with the proposed method, using isotope dilution for calibration, and the results obtained were in excellent agreement with the certified value (within experimental uncertainty).

Accurate determination of ultra-trace levels of Ti in blood serum using ICP-MS/MS.

Ti is frequently used in implants and prostheses and it has been shown before that the presence of these in the human body can lead to elevated Ti concentrations in body fluids such as serum and urine. As identification of the exact mechanisms responsible for this increase in Ti concentrations, and the risks associated with it, are not fully understood, it is important to have sound analytical methods that enable straightforward quantification of Ti levels in body fluids (for both implanted and non-implanted individuals). Until now, only double-focusing sector field ICP-mass spectrometry (SF-ICP-MS) offered limits of detection that are good enough to deal with the very low basal levels of Ti in human serum. This work reports on the development of a novel method for the accurate and precise determination of trace levels of Ti in human serum samples, based on the use of ICP-MS/MS. O2 and NH3/He have been compared as reaction gases. While the use of O2 did not enable to overcome all spectral interferences, it has been shown that conversion of Ti(+) ions into Ti(NH3)6(+) cluster ions by using NH3/He as a reaction gas in an ICP-QQQ-MS system, operated in MS/MS mode, provided interference-free conditions and sufficiently low limits of detection, down to 3 ng L(-1) (instrumental detection limit obtained for the most abundant Ti isotope). The accuracy of the method proposed was evaluated by analysis of a Seronorm Trace Elements Serum L-1 reference material and by comparing the results obtained with those achieved by means of SF-ICP-MS. As a proof-of-concept, the newly developed method was successfully applied to the determination of Ti in serum samples obtained from individuals with and without Ti-based implants. All results were found to be in good agreement with those obtained by means of SF-ICP-MS. The typical basal Ti level in human serum was found to be <1 μg L(-1), while values in the range of 2-6 μg L(-1) were observed for implanted patients.

High-resolution continuum source graphite furnace atomic absorption spectrometry for direct analysis of solid samples and complex materials: a tutorial review

The purpose of this review is to examine the literature devoted to direct sample analysis using high-resolution continuum source atomic absorption spectrometry in a tutorial way, in an attempt to provide guidelines on the most critical issues to consider when developing a new method. This review discusses in detail the advantages and limitations of this technique, highlighting its benefits in comparison with classic line source atomic absorption spectrometry instrumentation in the context of direct analysis of solid samples, slurries and complex liquid samples, trying to establish in which situations the use of this technique can be particularly beneficial. Some of the aspects that are addressed comprise: (i) the improved potential to detect and correct for spectral interferences; (ii) the different options to adjust the sensitivity to the analyte content; (iii) strategies to minimize matrix effects and calibrate with aqueous standard solutions; (iv) possibilities to carry out multi-element analysis.

High-resolution continuum source graphite furnace atomic absorption spectrometry: Is it as good as it sounds? A critical review

AbstractThe recent arrival of high-resolution continuum source atomic absorption spectrometry represents a potential revolution in this field, in particular for direct analysis of complex samples. This review tries to illustrate the main advantages of this technology, paying particular attention to the development of direct solid sampling methods. Three solid sampling applications will be discussed, each one of them highlighting one of the main advantages of this technique. The review also intends to clarify some misconceptions on the true potential of the instrumentation that is currently commercially available, such as its performance for multielemental analysis. FigureGraphite furnace: still burning hot!

Characterization of cobalt pigments found in traditional Valencian ceramics by means of laser ablation-inductively coupled plasma mass spectrometry and portable X-ray fluorescence spectrometry

In this work, a comparison of the performances of laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) and portable X-ray fluorescence (XRF) spectrometry for the characterization of cobalt blue pigments used in the decoration of Valencian ceramics is presented. Qualitative data on the elemental composition of the blue pigments obtained using both techniques show a good agreement. Moreover, the results clearly illustrate that potters utilized different kinds of cobalt pigments in different historical periods. While both techniques seem suitable for the proposed task, they show different strengths and weaknesses. Portable X-ray fluorescence spectrometry is a cheaper and totally non-destructive technique, capable of providing fast and reliable results at the mgg(-1) level. LA-ICPMS, on the other hand, offers a much higher detection power and better spatial resolution, but its use results in some sample damage (sample consumption at the mug level), while it is a more expensive and non-portable technique.