Total reflection X-ray fluorescence spectrometry for trace determination of iron and some additional elements in biological samples

Abstract

Trace elements are essential for life and their concentration in cells and tissues must be tightly maintained and controlled to avoid pathological conditions. Established methods to measure the concentration of trace elements in biological matrices often provide only single element information, are time-consuming, and require special sample preparation. Therefore, the development of straightforward and rapid analytical methods for enhanced, multi-trace element determination in biological samples is an important and raising field of trace element analysis. Herein, we report on the development and validation of a reliable method based on total reflection X-ray fluorescence (TXRF) analysis to precisely quantify iron and other trace metals in a variety of biological samples, such as the liver, parenchymal and non-parenchymal liver cells, and bone marrow-derived macrophages. We show that TXRF allows fast and simple one-point calibration by addition of an internal standard and has the potential of multi-element analysis in minute sample amounts. The method was validated for iron by recovery experiments in homogenates in a wide concentration range from 1 to 1600 μg/L applying well-established graphite furnace atomic absorption spectrometry (GFAAS) as a reference method. The recovery rate of 99.93 ± 0.14% reveals the absence of systematic errors. Furthermore, the standard reference material "bovine liver" (SRM 1577c, NIST) was investigated in order to validate the method for further biometals. Quantitative recoveries (92-106%) of copper, iron, zinc, and manganese prove the suitability of the developed method. The limits of detection for the minute sample amounts are in the low picogram range. Keywords Total reflection X-ray fluorescence spectrometry. Iron trace analysis. Biometal trace analysis. Bone marrow-derived macrophages. Liver cells. Liver tissues Published in the topical collection featuring Female Role Models in Analytical Chemistry.

Hfe Actions in Kupffer Cells Are Dispensable for Hepatic and Systemic Iron Metabolism

“…Total iron content in primary cells was measured via total-reflection X-ray fluorescence (TXRF) or inductively coupled plasma optical emission spectrometry (ICP-OES) (Ciros Vision, SPECTRO Analytical Instruments GmbH, Kleve, Germany) after wet-washing the samples with 65% nitric acid (Merck), as previously described [15,16]. In short, cell pellets were digested with high-purity concentrated HNO 3 (HNO3, 63% AnalR Normapur, VWR International GmbH, Darmstadt, Germany; sub-boiled, DST-1000 Acid Purification System, Savillex, Eden Prairie, MN, USA).…”

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…Gruber et al 100 utilised TXRF spectrometry for quantitative analysis of various biological samples , namely liver, parenchymal and non-parenchymal liver cells, and bone marrow-derived macrophages. Either Ga or Ti was added as an internal standard for single point calibration; the selection of which depended on the sample type as Ga suffered from Zn overlap especially in liver tissues and some samples types were found to contain Ti (bone marrow-derived macrophages).…”

Multi-Elemental Analysis of Hair and Fingernails Using Energy-Dispersive X-ray Fluorescence (ED XRF) Method Supported by Inductively Coupled Plasma Mass Spectrometry (ICP MS)

“…Many metals in biological materials occur in trace amounts, requiring sensitive instrumental techniques. The most commonly used are atomic absorption spectroscopy (AAS) with atomization in a graphite furnace (in a few cases in a flame) [ 11 , 12 , 13 , 14 ], optical emission spectrometry [ 15 , 16 ], mass spectrometry [ 4 , 5 , 6 , 17 , 18 ] with plasma as a source of excitation or ionization of elements (ICP OES, ICP MS), and total reflection X-ray fluorescence spectrometry (TXRF) [ 19 , 20 ]. In addition to the high operating costs typical of these techniques, they require sample mineralization [ 5 , 6 , 16 , 21 ] or extraction combined with preconcentration [ 13 , 16 , 18 , 22 ].…”