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In recent years, the conceptual advancement on green analytical chemistry (GAC) has moved in parallel with efforts to incorporate new screening or quantitative low-cost analytical tools to solve analytical problems. In this sense, the role of solid state techniques that allow the non-invasive analysis (or with a minimum sample treatment) of solid samples cannot be neglected. This review describes the basic principles, instrumentation and advances in the application of X-ray fluorescence instrumentation to the environmental sciences research topics, published between 2006 and 2020. Obviously, and because of the enormous number of works that can be found in the literature, it is not possible to exhaustively cover all published articles and the diversity of topics related to the environment in which a solid state technique like XRF has been applied successfully. It is a question of making a compilation of the instrumentation in use, the significant advances in XRF spectrometry and sample treatment strategies to highlight the potential of its implementation for environmental assessment.

In this contribution, the analytical potential of total reflection X-ray fluorescence (TXRF) instrumentation has been evaluated for the determination of major and trace elements in milk powder. TXRF allows the possibility of direct analysis of solid suspensions without the need for a digestion process and therefore it can be a potential analytical candidate for simple and cost-effective analysis. A detailed study to select sample preparation and measurements conditions was carried out. Different quantification approaches (including internal standardization and empirical calibration) were also tested. Finally, the developed TXRF methods (W anode) were validated by a strict comparison with the data from the reference methods on a set of twenty-three samples using robust statistics. Results showed that acceptable results can be obtained for K, Ca, Fe and Zn determination if using adequate calibration approaches. Otherwise, only screening results can be obtained for light elements (P and Cl) in milk powder samples.

This contribution describes the study conducted on two painted wooden reliefs created in the early 1970s by Vasko Lipovac, a prominent Croatian contemporary artist. Due to the poor condition in which the artworks were found, it was important to establish a strategy for conservation and long-term preservation. Accordingly, preliminary knowledge about chemical composition of the paint pigments and binders was pointed out as significant information addressed in this study. Since the chemical composition of the paint determines the conservation methodology and materials, the proper treatment ensures stability of the original materials, and accordingly, long term preservation of an artwork. An integrated analytical approach involving different instrumental analytical techniques was applied to each of the microsamples collected in the paintings. For the elemental characterization of the pigments, total reflection X-ray fluorescence spectroscopy (TXRF) was used, and the obtained results were complemented with the information about mineral phases present in the pigments by X-ray diffraction (XRD) analysis. The TXRF results demonstrated that most of the pigments related with the named “skin tone” contain appreciable amounts of Cd (1.8–9%) with constant presence but variable amounts of Se (0.24–1.1%), reinforcing the interpretation that the pigment originally used is cadmium sulfoselenide (the so-called “cadmium red”), although by XRD we only observed the presence of its alteration to cadmium sulfate. The XRD results revealed a complex mixture of different inorganic compounds present in the painted wooden reliefs (i.e., barite, rutile, quartz, calcite, chlorite, etc). The presence of zinc white with wurtzite structure in almost all the samples can be considered as the main constituent of the coloring painting layer. Raman spectroscopy contributed to a more accurate characterization of the analysed paint samples, since the vibrational spectra as a result of Raman scattering pr

In most clinical and nutritional studies, it is of significance to know information about the multielemental composition of biological samples. Conventional analysis of biological samples relies upon sample digestion followed by atomic spectrometry detection. This approach is essential for the quantification of ultratrace elements in biological samples. While in other applications it could be of interest to have simpler analytical methods with multielemental capability but involving a minimum sample treatment, reduce the amount of sample and a more cost-effective analysis. In the present contribution, the possibilities and drawbacks of simple sample treatments (i.e., dilution and suspension) in combination with total reflection X-ray fluorescence spectrometry (TXRF) for the analysis of different types of biological samples have been critically evaluated. For that, a set of reference materials or well-characterized biological human fluids (blood, serum, plasma and seminal plasma) and animal/vegetal tissues have been used to estimate the analytical capabilities in terms of limits of detection, trueness and precision of the proposed TXRF methods. The results are based on the authors' experience in analysing biological samples using TXRF, and it is expected that they can be useful for new TXRF users in this field and they can provide a good basis for further application of this technique in clinical studies and other applications dealing with the analysis of biological samples in the future.

In this paper, the determination of ultratrace heavy metal ions was developed by combining a preconcentration method using graphene oxide/carbon nanotubes membranes (GO/CNTs) and total-reflection X-ray fluorescence spectrometry (TXRF). Due to the excellent adsorptive properties of the GO, the foregoing membranes are suitable for effective simultaneous sorption of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) from aqueous solutions. In this method, the aqueous solution is passed through the GO/CNTs membrane. The analytes are eluted from the GO and afterward transferred onto a siliconized quartz reflector for further TXRF analysis using W and Mo target X-ray tubes. The maximum recoveries for all the elements were obtained at pH 5; thus it was chosen for all further experiments. The face centered central composite design was performed to study the influence of the flow-rate and volume of the solution on the recovery of the determined metal ions. Recovery values higher than 96% for all studied metals allow performing efficient preconcentration with an enrichment factor of 133, achieving the limits of detection (LODs) in the range of 0.08–0.21 ng mL−1 for W target X-ray tube with a measurement time of 2000 s, and much lower LODs for Mo target X-ray tube: 0.001–0.002 ng mL−1 with the exception for Cd (0.11 ng mL−1) with a very short measurement time of 600 s. Certified reference materials of spring water and seawater were examined to verify the reliability of the method. The evaluated procedure does not require toxic reagents or organic solvents, thus minimizes the portion of the sample for TXRF measurement, and stands in good accordance with green analytical chemistry basic principles.

Trace elements are essential for the normal spermatogenesis of mammals and play a critical role in sperm quality and pathological processes e.g. inflammation. Consequently, multi-elemental analysis of seminal plasma (SP) may provide significant information on physiological and pathophysiological processes occurring in the male reproductive tract. Therefore, the development of a simple, fast and reliable method for seminal plasma (SP) analysis by total reflection X-ray fluorescence spectrometry (TXRF) could be useful for both, scientific and clinical studies. In this study, a detailed assessment of the sample preparation parameters and measurement conditions, including analysis ofthe shape and element distribution of the deposited residue on the reflector by micro X-ray fluorescence spectrometry, was carried out. Using the best analytical conditions, limits of detection for trace elements were found to be in the range of 0.04-0.3 mg kg-1. Trueness and precisionof the results, evaluated by spiked SP sample analysis, were in most cases acceptable with recoveryvalues in the range of 87-109% and relative standard deviations 3-12% (n = 5). The developed TXRF method was applied for the analysis of several SP samples from patients with different diagnoses andthe results were compared with those obtained by ICP-OES. Among the studied trace elements with a role in the antioxidant defence system only Zn could be quantified and some differences in Zn concentrations among studied groups were observed. However, further studies on a large number of samples are required to define the exact relationship between the element composition and semen quality.

Exposure to arsenic (As)through drinking water results in accumulation of As and its methylated metabolites in several organs, promoting adverse health effects, particularly potential development of cancer. Arsenic toxicity is a serious global health concern since over 200 million people are chronically exposed worldwide. Abundant biochemical and epidemiological evidence indicates that the kidney is an important site of uptake and accumulation of As, and mitochondrial damage plays a crucial role in arsenic toxicity. However, non-destructive analyses and in situ images revealing As fate in renal cells and tissue are scarce or almost non-existent. In this work, kidney tissue from exposed rats was analyzed by EDXRF (Energy dispersive X-ray fluorescence), micro-SRXRF (micro X-ray Fluorescence using Synchrotron Radiation), SRTXRF (SRXRF in total reflection condition), SEM-EDX (Scanning Electron Microscope in combination with EDXRF)and SRXRF-XANES (SRXRF in combination with X-ray Absorption Near Edge Spectroscopy). Our results provide evidence of renal cortex distribution of As with periglomerular localization, co-localization of S, Cu and As in subcellular compartment of proximal tubule cells, mono-methylarsonous acid accumulation in renal cortex mitochondria, and altered subcellular concentration and distribution of other elements. © 2019

Multielemental analysis of whole blood can provide significant information for the evaluation of nutritional status and diagnosis of certain diseases as well as for the assessment of exposure to potentially toxic metals. However, the quantification of multiple elements in whole blood is not easy partly because of the wide variation in element concentrations (from ng L −1 to g L −1 ) and the complex matrix. The aim of this work was to develop a fast, sustainable, and reliable analytical method, in combination with low-power TXRF, for multielemental analysis of blood samples. Firstly, a set of experiments were carried out to select the best diluent type and dilution factor using the control material SeronormTM Trace Elements Whole Blood L-1. A critical evaluation of the parameters affecting the sample deposition on the reflector was also carried out including a study of the shape and element distribution of the deposited residue on the reflector by micro X-ray fluorescence spectrometry. Using the best analytical conditions, limits of detection estimated were in the low milligrams per kilogram range and similar to those obtained using more complex sample treatments such as digestion. Accuracy and precision of the results were in most cases acceptable (recoveries 89–102%, RSD 6–8%, n = 5). Only underestimated values were obtained for light elements such as potassium. To prove the applicability of the method, several blood samples from control and thyroid disease patients were analyzed. Despite the fact that more samples need to be analyzed, it seems that Zn and Br contents in some of the patients are significantly higher compared to control samples. [Figure not available: see fulltext.]. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

The production of silver nanoparticles (AgNPs)has increased tremendously during recent years due to their antibacterial and physicochemical properties. As a consequence, these particles are released inevitably into the environment, with soil being the main sink of disposal. Soil interactions have an effect on AgNP mobility, transport and bioavailability. To understand AgNP adsorption processes, lab-controlled kinetic studies were performed. Batch tests performed with five different Mediterranean agricultural soils showed that cation exchange capacity and electrical conductivity are the main parameters controlling the adsorption processes. The adsorption kinetics of different sized (40, 75, 100 and 200 nm)and coated (citrate, polyvinylpyrrolidone and polyethyleneglycol (PEG))AgNPs indicated that these nanoparticle properties have also an effect on the adsorption processes. To assess the mobility and bioavailability of AgNPs and to determine if their form is maintained during adsorption/desorption processes, loaded soils were submitted to leaching tests three weeks after batch adsorption studies. The DIN 38414-S4 extraction method indicated that AgNPs were strongly retained on soils, and single-particle inductively coupled plasma mass spectrometry confirmed that silver particles maintained their nanoform, except for 100 nm PEG-AgNPs and 40 nm citrate-coated AgNPs. The DTPA (diethylenetriaminepentaacetic acid)leaching test was more effective in extracting silver, but there was no presence of AgNPs in almost all of these leachates. © 2019