Analytical noteAnalysis of nutrition-relevant trace elements in human blood and serum by means of total reflection X-ray fluorescence (TXRF) spectroscopy☆
Introduction
Since the publication by Prange et al. [1], total reflection X-ray fluorescence has been established as a versatile tool for the analysis of trace elements in blood and serum samples. With this, the main application fields are the analysis of toxic elements [2] and medical investigations [3], [4]. Additionally, the improvement of detection limits and accuracies by means of enhanced sample preparation techniques, as published by Savage and Haswell [5], was a topic of several analytical studies.
However, one of the major analytical tasks in routine whole blood and serum analysis is the determination of nutrition-relevant trace elements. Among these, elements of crucial importance are Cu, Fe, Zn, and Se [6], [7], [8], [9]. The most established methods for the determination of these elements are Atomic Absorption Spectroscopy (ASS) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). As both methods have the disadvantages of a comparably complicated sample preparation and rather expensive analysis, total reflection X-ray fluorescence can be considered as a real analytical alternative.
The target of this study was to develop a method for the analysis of the nutrition-relevant elements with a minimum of sample preparation and measurement time, which still guarantees an accurate and reproducible analysis. For comparison purposes, additional measurements were performed with several certified reference standards, applying different preparation techniques, including microwave digestion and cold plasma ashing.
Section snippets
Instrumentation
All measurements presented in this paper were performed with the benchtop TXRF spectrometer “S2 PICOFOX” (Bruker AXS Microanalysis, Berlin, Germany). The technical specification of this instrument is summarized in Table 1.
Samples
For this study, the six differently certified reference standards “Serum ClinChek L1”, “Serum ClinChek L2”, “Serum ClinCal Calibrator”, “Whole blood ClinCal Calibrator” (Recipe) “Whole blood Seronorm L1” and “Whole blood Seronorm L2” (Sero) were analyzed. These reference
Accuracy
The results of the serum measurements are summarized in Table 2. Taking the confidence level of the reference values into account, it can be stated that the correspondence of the TXRF and the reference values are excellent for the elements Cu, Zn, and Se. For Fe a systematic overestimation, most probably caused by contamination, was observed.
A comparison of the reference standard confidence level values with the standard deviations of the TXRF measurements, estimated by means of a fivefold
Conclusions
Several whole blood and serum reference standards were analyzed by means of TXRF spectroscopy after simple dilution and enhanced digestions preparation. It can be concluded that for a routine analysis of the nutrition-relevant elements Fe, Cu, Zn, and Se the fast and simple dilution of the samples with ultrapure water is sufficient. 10 μl of the internal standardized samples should be prepared on unsiliconized quartz glass sample carriers. With this, measurement times of 600 s while applying a
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2023, Journal of Trace Elements in Medicine and BiologyQuantification of gold nanoparticles in blood using total reflection X-ray fluorescence
2022, Spectrochimica Acta - Part B Atomic SpectroscopyCitation Excerpt :Total X-ray Reflection Fluorescence (TXRF) has established itself as an easy-to-use analytical technique that offers quantification of trace elements from various sample types ranging from liquids to powdered solids [16,17]. Simultaneous multielemental TXRF quantification with the use of an internal standard has allowed for biomonitoring of blood trace elements to study the influence of environmental pollutants [18,19], nutrition [20,21] and elemental imbalances in various disorders [22–26]. Given the rich matrix of blood and its influence on quantification, several studies have also investigated effect of sample pre-treatment on quantification of whole blood, plasma and serum [20,21,27–32].
Lead (Pb) exposure assessment in dried blood spots using Total Reflection X-Ray Fluorescence (TXRF)
2021, Environmental ResearchCitation Excerpt :At this stage, the internal standard was added to ensure that it bound to the sample matrix. We evaluated the performance of three internal standards (Ga, Ni, and Sr) previously studied for TXRF-based analysis of Pb (Silva et al., 2013; Stosnach, 2009; Martinez et al., 2004, Bounakhla, 2003), and decided upon the use of Ni at a final concentration of 150 ppb (Supplementary figure S2). As previous studies (including our own pilot efforts) have shown that the relatively high iron levels in blood interfere with TXRF-based detection of some elements (Prangue, 1989; Khunder, 2006), we included Methyl Isobutyl Ketone (MIBK) to the digested samples to extract out the iron (more details on the extraction process are in Supporting information S5).
Chemical analysis of cesium lead-halide perovskite nanocrystals by total-reflection X-ray fluorescence spectroscopy
2020, Spectrochimica Acta - Part B Atomic SpectroscopyCitation Excerpt :However, this analysis is quite expensive and requires access to a complex instrumentation, which is not widely available and easy to manage. Total-reflection X-ray spectroscopy (TXRF) is nowadays a well-established technique which is applied in several fields such as environmental science [10–12], geology [13–15], materials science [16], food science [17], medicine [18,19]. The advantages of TXRF over other analytical techniques are the low amount of sample required, fast sample preparation, easy sample pre-treatment, and relatively low costs for the instrumentation and its operation.
Level of minerals and trace elements in the urine of the participants of mountain ultra-marathon race
2017, Journal of Trace Elements in Medicine and BiologyCitation Excerpt :Beside multi-elemental analysis that allow analysis of higher number of elements from the same urine sample, TXRF method is simple and not time-consuming [28]. The applied TXRF method was validated as reported previously [11] and for quality control a certified urine reference sample (Seronorm urine level 2, SERO AS, Norway) was used. Additionally, obtained baseline values for urinary Zn, Se, Na, K, Ca and P in the present study were comparable to values reported previously confirming TXRF reliability [2,29–31].
Determination of As concentration in earthworm coelomic fluid extracts by total-reflection X-ray fluorescence spectrometry
2017, Spectrochimica Acta - Part B Atomic Spectroscopy
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This paper was presented at the 12th Conference on Total Reflection X-ray Fluorescence Analysis and Related Methods held in Trento (Italy), 18–22 June 2007.