The determination of rare earth elements (REEs) in refractory materials by inductively coupled plasma (ICP) spectrometry with conventional sample introduction using pneumatic nebulization requires the dissolution of these samples, which is difficult. This work presents an optimized method using electrothermal vaporization (ETV) coupled to ICP optical emission spectrometry (OES) for the direct determination of REEs in refractory geological materials. Solid sampling eliminates the dissolution step, thereby increasing sample throughput. Furthermore, the small sample mass required with ETV allows faster analysis with greater sensitivity than with nebulization by eliminating the dilution inherent to dissolution and introducing more sample into the plasma compared to nebulization. Point-by-point internal standardization with an argon emission line compensates for the visible sample loading effect on the plasma. Multivariate optimizations of the carrier, bypass, and CF4 reaction gas flow rates, along with optimization of the pyrolysis temperature and cooling time between the pyrolysis and vaporization steps, enhanced analyte signals by 2.9-11 times compared to a previous ETV-ICPOES method for the analysis of slag. Adding at least 30 μL of high-purity water to the graphite boat containing solid samples enhanced sensitivity by 61% on average and enabled external calibration using standard solutions, which provided accurate results for 14 REEs (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tm, Y, and Yb). In contrast, only REEs with certified concentrations in the CRMs encompassing those in the sample could be determined by using CRMs for external calibration.

This study investigates the leaching of toxic (Cd and Pb) and essential elements (Cu, Fe and Zn) from organic white, organic brown and basmati rice using the continuous on-line leaching method and a conventional batch method. The samples were maintained at 37 °C while being sequentially leached by artificial saliva, gastric juice and intestinal juice. Elements released were determined by inductively coupled plasma mass spectrometry, revealing over 60 % bio-accessibility in most instances. The total concentrations of Cd (140-150 μg kg-1) and Pb (150-170 μg kg-1) are near or exceed regulations in Europe. Washing rice prior to cooking reduced the toxic elements concentration by up to 50 % while preserving essential elements. However, consuming less than half a serving could still pose a health risk to a 20-kg child. Correlations between temporal leaching profiles of different elements revealed common sources of those elements, which differed between rice types, potentially enabling rice discrimination.

The tandem LIBS/LA‐ICPMS technique is a desirable tool for the multi‐elemental determination, characterization, and classification of alloys as forensic evidence. In this study, LIBS/LA‐ICPMS is validated for the forensic evaluation of lead‐free solder alloys, which form valuable evidence from post‐blast crime scenes involving homemade and improvised explosive devices. LIBS/LA‐ICPMS is competitive with other spectroscopic‐based forensic techniques as it is in situ, analyzes samples directly, and requires minimal destruction of the exhibit. Following a one‐standard calibration technique, nine major (alloying metals) and trace elements (impurities or additives) are quantified in lead‐free solders. Optimizing laser parameters and using Pb as a naturally occurring internal standard are shown to compensate for mass‐dependent drift and matrix effects. The quantitative results of Pb‐free certified reference materials align with certificate values and with results from two techniques in a cross‐validation comparison, including electrothermal vaporization‐inductively coupled plasma optical emission spectrometry and neutron activation analysis. Utilizing peak ratios in a model of principal component analysis is presented to identify key compositional differences among solders and provide a visual model for solder discrimination. Outcomes of this approach demonstrate the potential for associating or discriminating lead‐free solders, including different solders from the same manufacturer. Together, this technique can establish chemical concordance among known and questioned materials and offers a utilitarian approach for the forensic assessment of trace evidence.

Spectroscopic interferences have long negatively impacted the accuracy of inductively coupled plasma mass spectrometry (ICPMS) analyses. Of these, oxide-based interferences, the combination of an analyte with oxygen producing a new ion 16 mass units greater than the original analyte, often proves most prevalent and difficult. A cheap and reliable method that permits the mitigation of oxide-based interference would be highly beneficial. Here-in, low sample uptake rate was used to reduce the formation of lanthanide oxide-based interferences in ICPMS analyses through temperature and Le Ch & acirc;telier effects. Introduction of oxide forming solutions (50 mu g L-1) composed of lanthanide elements at 1 mL/min yielded an average oxide ratio of 4.5 +/- 7.2% while introduction at 50 mu L L min-1yielded 0.54 +/- 0.26%. A similar method using 2% nitrogen gas in the bulk plasma concurrently decreased oxide-based interferences. The benefits observed with low sample uptake rate and a mixed-gas plasma were combined to virtually eliminate oxide based-interferences for many of the lanthanide elements and provide a modest signal enhancement compared to an Ar plasma operated at a higher sample uptake rate. For example, when comparing the best oxide reduction method to the worst, oxide formation is mitigated by 97%. Of the three sample uptake rates tested, 235 mu L min-1under mixed-gas plasma conditions offers the best balance between the oxide interferences mitigation and signal intensity. Ultimately, low sample uptake rate may prove essential in increasing ICPMS analysis accuracy while safeguarding resources and minimizing chemical waste for generations to come.

This paper describes the use of an ionic liquid ferrofluid for the preconcentration and simultaneous ultra-trace determination of inorganic As and Se species in waters by inductively coupled plasma mass spectrometry. An ultrasound-assisted sol-gel method was used for the synthesis of silica and titania coated and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane functionalized magnetic nanoparticles (SCTCMNPs-AEAPTMS). The structural features of the SCTCMNPs-AEAPTMS were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy. Experimental conditions, including the sample solution pH, elution time, and eluent concentration, were optimized. After oxidation of As(III) and Se(IV) to As(V) and Se(VI) by using H2O2, the total concentrations of As and Se were determined and those of As(III) and Se(IV) were obtained through subtraction of the concentration of As(V) and Se(VI) from the total concentrations. Under the optimal experimental conditions, the detection limitfor As(V) and Se(VI) were 0.3 ng L-1and 0.2 ng L-1respectively. The accuracy of this method was verified by analyzing a certified reference material (1568a Rice Flour): the measured As and Se concentrations agreed with the certified values based on a Student's t-test at the 95% confidence level. The proposed method was also successfully applied to the preconcentration and ultra-trace determination of As and Se species in different water samples.

Applications of electrothermal vaporization coupled to inductively coupled plasma optical emission spectrometry (ETV-ICPOES) may require offline, and often manual, processing for data compilation and optimization. Techniques for data processing have traditionally applied internal standardization and some form of correction (e.g., blank subtraction) to compensate for positive bias from the background. However, a blank may not always be easily obtained in applications of solid-sampling research, and in some cases, degrade detection limits and signal integrations. In this work, several data processing techniques are evaluated, after point-by-point internal standardization with an Ar emission line, for the sensitive and accurate analysis of solder by ETV-ICPOES: peak area with average blank subtraction from empty graphite boats (Technique A), peak area with integrated background correction (Technique B), and peak height with averaged background correction (Technique C). Despite being the simplest to implement, subtracting the average background signal from the height of the peak produced during the vaporization step, i.e., Technique C, systematically yields the lowest detection limits without compromise in accuracy or precision.

Alternative protein sources such as insects are of interest because of their many nutritional and ecological benefits compared to traditional animal-based proteins. As they may contain potentially toxic elements in addition to essential elements, their analysis is important to ensure their safety for human consumption. To avoid time-consuming acid digestion, which may lead to contamination or loss of analytes, the direct analysis of insects via solid sampling electrothermal vaporization coupled with inductively coupled plasma optical emission spectrometry (SS-ETV-ICPOES) was explored for the first time. Different approaches for the analysis of black soldier fly meal were evaluated, using CF4, polytetrafluoroethylene (PTFE) powder pre-mixed with the sample, or PTFE pre-mixed with the sample and H-2 in the carrier gas as chemical modifier. Addition of N-2 as a sheathing gas around the ETV effluent to increase plasma robustness was also studied. The best results were obtained with the Ar-N-2 mixed-gas plasma, PTFE powder pre-mixed with samples, and H-2 in the carrier gas, allowing the accurate determination of Cd, Co, Fe, K, P, S, and Zn in black fly soldier meal in 100 s by external calibration with a dogfish muscle certified reference material (CRM) and internal standardization with Ar 404.442 nm to compensate for sample loading effects on the plasma. Application of this method to other insects resulted in accurate results for Co, Fe, and S in cricket flour as well as Co, Fe, P, S, and Zn in mealworm powder. Thus, SS-ETV-ICPOES shows promise as a screening method for insect analysis.

Herein, a simple and fast method was developed for efficient preconcentration of anionic Cr(VI) in drinking water using, for the first time, an ionic liquid ferrofluid (IL-FF) for its interference-free ultra-trace (ng L -1 ) determination by inductively coupled plasma mass spectrometry.To improve the selectivity of the IL-FF, the surface of commercially available Fe3O4 magnetic nanoparticles (MNPs) was coated with silica and functionalized with L-cysteine (SCMNPs-Cys).The structural features of the SCMNPs-Cys were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, and X-ray diffraction.Experimental conditions, including the sample solution pH, elution time, and eluent concentration, were optimized.A 20-fold enrichment factor resulted in a limit of detection of 3 ng L -1 .The applicability of the method was confirmed by the analysis of Cr(VI) in different water samples with recoveries of 84-91% (n=3).

Nanoparticles (NPs) are ubiquitous because they find applications in nanomedicine, materials science, and consumer products to name a few, and eventually end up in the environment. The various techniques available to analyze NPs each have strengths and limitations. This study focuses on improving the single particle inductively coupled plasma mass spectrometry (spICPMS) technique to address the limitations of existing methods and improve the size detection limit for Pt and Au NPs. Infrared heating of the spray chamber and connection to the torch is used to pre-evaporate the aerosol and improve the transport efficiency. Eight modified cyclonic spray chambers with a volume ranging from 25 to 125 mL, where an IR emitter is inserted in a modified baffle and the gap between the top of the baffle and the top service of the spray chamber was varied, are tested for the characterization of NPs to see their effect on sensitivity, detection limit, and transport efficiency. The results indicate that the 50 mL modified spray chamber with a 2 mm gap between the top of the baffle and the top service of the spray chamber offers the best detection limit for Pt. It enhances sensitivity and precision and allows accurate characterization of Au and Pt NPs without any measurement of the transport efficiency. Furthermore, this sample introduction system provided similar improvements in sensitivity and detection limit when used with the same nebulizer on two different spICPMS instruments. A compact infrared-heated sample introduction system allows total consumption, thereby allowing the analysis of nanoparticles without measurement of transport efficiency.

In forensic science, trace evidence establishes links between victims, suspects, and crime scenes. Head hair commonly serves as a reliable biomarker because it contains a permanent record of elements from an individual's body. By substituting CF4 reaction gas for polytetrafluoroethylene powder, this work modifies and re-optimizes a previous method for determining the sex of humans by directly analyzing hair samples via electrothermal vaporization with detection by inductively coupled plasma optical emission spectrometry. Hair samples were washed in portions of doubly deionized water, dried, and ground into a fine powder before analysis. Data processing included the use of an Ar emission line to compensate for sample loading effects on the plasma via point-by-point internal standardization. The peak areas were then integrated before multivariate analysis by principal component analysis (PCA) and linear discriminant analysis (LDA). Using the same predictor elements as the original method (Mg, S, Sr, and Zn), LDA and PCA remained effective at accurately predicting the sex of female and male samples despite using a different chemical modifier and instrumental operating conditions, indicating method robustness. This work thus offers an alternative method that uses a more affordable and accessible carrier agent at no cost to the original method's reliability.

Edible insects are becoming increasingly popular as protein alternatives to traditional animal-based products. As such, information on their elemental composition is important to ensure they are safe for human consumption. This article describes the development and validation of a rapid, reliable method for the simultaneous determination of 19 elements (Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Pb, Se, Sr, and Zn) in edible insects by inductively coupled plasma mass spectrometry (ICP-MS) following closed vessel microwave digestion. The method was validated using three insect certified reference materials, namely black soldier fly larvae meal (BFLY-1), cricket flour (KRIK-1), and mealworm powder (VORM-1). The method was applied to analyze twelve different (whole) insect species. The maximum amount of each sample was calculated for As, Cd, and Pb with respect to their provisional tolerable daily intake values established by the Food and Agricultural Organization/World Health Organization. Most of the samples, except for scorpions and tarantulas, were safe to consume at large doses (1000-10,000 insects per day). Furthermore, most of the samples contained high levels of Fe, K, Na, and Zn, providing a preliminary overview of the nutritional profile of these novel protein alternatives.

Lead-tin solder is a useful piece of evidence from a crime scene and may be examined for information related to the construction or source of an improvised explosive device (IED).A technique based on electrothermal vaporization into inductively coupled plasma optical emission spectrometry was improved for the direct quantification of trace and major elements in solder (Ag, As, Bi, Cr, Fe, Sb, Sn).NIST 1728, a tin-alloy certified reference material, was used for external calibration and achieve a direct, fully solid-sampling procedure using only 0.5-3.0mg of sample.Point-by-point internal standardization with Ar 404.442 nm was performed to compensate for sample loading effects on the plasma, and a background correction technique was introduced to improve the overall efficiency of analysis.As solder was observed to change composition during some mock scenarios of IED preparation, which limits how solder can be examined in forensics, different soldering conditions (temperature, solder size, cleaning of the soldering tip or not between subsequent samples) were studied using an Fetip soldering device.Statistical analyses including Student's t-tests and a one-way analysis of variance revealed that none of these conditions resulted in contamination of the melted solder sample, hence confirming the viability of the mock procedure used to replicate IED soldering in research.A new qualitative discrimination method is introduced and demonstrated in a blind trial for matching and discriminating lead-tin solders.This method represents an improvement from past research and has potential for use in evaluating other forensic evidence involving ferrous-alloys.

Modifying a sex determination method involving multi-elemental hair analysis enabled successful application to dyed hair and hair from close relations.

Interfacial engineering of electrocatalysts is a pivotal approach for promoting the energy conversion efficiency of water electrolysis systems. Anchoring clusters or even single atoms of a foreign element on the surface of a support, usually 3D structured, can alter its local electronic structure leading to superior electrocatalytic activity. Herein, we report a method to decorate a 3D fractal Ni electrode with Ir atoms via a galvanic displacement reaction. The resulting electrode has a very low Ir loading of 1.6 mu mole cm(geo)(-2), with iridium atoms present as 4-5 nm diameter nanoclusters on the electrode surface. The activity for the electrochemical oxygen evolution reaction (OER) of the 3D fractal Ni electrode was improved by decoration with Ir, resulting in an overpotential of 195 mV at 10 mA cm(-2) and a Tafel slope of 44 mV dec(-1). Apart from increasing the electrocatalytic activity for the OER due to the very presence of more active iridium atoms, the galvanic displacement reaction resulted in a factor 8-10 increase of the electrochemically active surface area due to the creation/ activation of a secondary pore structure that contributes also to the better electrocatalytic performance of the resulting electrode. Using operando acoustic emission, it is demonstrated that the galvanic displacement reaction and the presence of Ir nanoclusters have the additional effect of reducing the average O-2 bubble size formed during the OER. As a result, the blocking effect of O-2 bubbles at high current density is less drastic than on the 3D fractal Ni electrode, resulting in a less severe decrease of the electrochemically active area at large current density. All three effects contribute toward improving the OER performance of the Irdecorated 3D fractal Ni electrode.

To analyze trace evidence found at crime scenes, non-destructive analysis techniques or analysis techniques requiring minute amounts of sample are preferred. One such technique is solid sampling electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICPOES), which requires only 0.1-5 mg of sample. As a result, it has been utilized in several applications of forensic research. This article discusses the capabilities of ETV-ICPOES among current analytical methods and introduces its value as a tool for the analysis of forensic evidence. The latest advancements of ETV-ICPOES demonstrate the diverse opportunities for the identification, determination, and discrimination of evidence. Methods of ETV-ICPOES for the direct analysis of various physical evidence, including trace evidence, are reviewed. Some methods involve quantification of multiple elements using, commonly, matrix-matched external calibration with certified reference materials. Other methods combine qualitative multi-element analysis, based on the area of each analyte peak produced during the vaporization step of the ETV temperature program, and multivariate analysis using principal component analysis or linear discriminant analysis. In all cases, internal standardization with an argon emission line first compensates for sample loading effects on the plasma. Perspectives for utilizing ETV-ICPOES in future forensic settings are also offered.

Single particle inductively coupled plasma mass spectrometry (spICPMS) can count and weigh metal-containing nanoparticles (NPs), enabling their sizing if their geometry, density, and composition are known.

A novel sampling probe composed of a coaxial-tube that functions at a continuous-flow was used to inject 1 mu L of sample into an inductively coupled plasma mass spectrometer. Simply touching a sample to the dome of liquid at the inlet of the liquid microjunction (LMJ) allows for sample introduction into a flowing carrier stream that transports sample into the plasma-similar to the mechanism of sample transport in flow injection analysis. This self-cleaning sampling system, allows for sampling of minute amounts of liquids at atmospheric pressure as well as leaching of soluble components off the surface of a solid. Preliminary results demonstrate the implementation of this probe in steady-state, flow injection, and surface sampling modes. A substantial reduction of matrix effects and oxide interferences resulted with 1 mu L injections. In fact, the performance of LMJ with 1 mu L injections in terms of spectroscopic and non-spectroscopic interference mitigation, sensitivity and detection limit is very similar to that previously reported with 1 mu L mono-segmented flow analysis.

The continuous on-line leaching method is comparable to batch methods for assessment of food safety but allows sourcing of elements.

Non-spectroscopic (also called matrix effects) and spectroscopic interferences (in particular, from oxide and doubly-charged ions) may compromise the accuracy of inductively coupled plasma mass spectrometry measurements. Dilution is widely used to reduce the matrix effects that depend on the absolute quantity of matrix. However, dilution is a source of errors (especially when performed manually) and takes considerable time. An alternative method of reducing the absolute quantity of matrix is proposed in this article, through a reduction in sample injection volume. In this study, capillary-based mono-segmented flow analysis (MSFA) with sample injection as small as 1 mu L was compared to the continuous nebulization of sample solutions and flow injection of 50-mu L aliquots. The injection volume and oxide interference had a positive correlation, with 1-mu L MSFA reducing the amount of CeO+/Ce+ by up to 69%. The concurrent increase in Ba++/Ba+as the sample volume decreased suggests an increase in plasma temperature when smaller sample volumes are introduced. Signal suppression induced by the 400-mg L-1 Na matrix significantly decreased as the volume of the injected sample decreased and was virtually eliminated with 1-mu L MSFA. This decrease translated into a negative correlation between the sample volume and accuracy when a drinking water-certified reference material was analyzed by external calibration without internal standardization or matrix matching. Only 1-mu L MSFA yielded concentrations within the range of inclusion for all analytes.