1. Method development and production of an ambient-stable blood certified reference material for total mercury, methylmercury, and trace elementsKoichi Haraguchi, Mineshi Sakamoto, Hiromitsu Nagasaka, Milena Horvat, Ermira Begu, Polona Klemenčič, Adna Alilović Osolin, Masaaki Nakamura, 2026, original scientific article Abstract: Background. Certified reference materials (CRMs) for mercury speciation of biological fluids have hitherto been limited to frozen or cold-storage types, which impedes the participation of laboratories in tropical or remote regions. Existing CRMs often do not fully meet user needs, particularly regarding storage stability and concentration relevance. Results. Using pooled Japanese human blood, we developed a freeze-dried, ambient-stable blood CRM, with certified values of 6.16 μg L−1 for total mercury (THg) and 5.46 μg L−1 for methylmercury (MeHg, as Hg). These concentrations are congruent with median exposure levels in fish-consuming populations (e.g., small island states and riverine Amazonian communities) derived from global biomonitoring data. Homogeneity, stability, and traceability were validated through inter-laboratory comparisons and rigorous uncertainty assessment. Significance. This ambient-stable blood CRM broadens global access to high-quality QA/QC of mercury speciation, especially in regions lacking cold-chain infrastructure. It contributes to capacity building under the Minamata Convention and strengthens interlaboratory comparability. Registration in COMAR and international collaborative deployment are under active development, enhancing the global infrastructure for mercury biomonitoring.
Keywords: passive monitoring, methylmercury, blood samples, mercury detection, human biomonitoring, trace elements
Published in DiRROS: 04.05.2026; Views: 139; Downloads: 106
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2. Optimisation of a sample preparation method for the determination of multi-elemental compositions in human hair by triple quadrupole ICP-MS analysisAgneta Annika Runkel, Marta Jagodic Hudobivnik, Igor Živković, Polona Klemenčič, Darja Mazej, Milena Horvat, 2026, original scientific article Abstract: Monitoring toxic elements has a long tradition in Slovenia due to historical mining. More recently, attention has shifted to essential elements, since both deficiencies and excesses can harm health. Regular monitoring of (non-)essential elements supports risk assessment and policymaking. While urine and blood are common biomonitoring matrices, hair offers a non-invasive alternative that reflects exposure over several months, though standardised methodologies for hair analysis remain limited. This study aimed to develop and validate a sensitive and robust analytical method for the determination of 29 elements in human hair, addressing key challenges in sample preparation and contamination control. We developed a sensitive and robust method for the determination of 29 elements (Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Se, Sn, Sr, Ti, U, V, and Zn) in 3 cm segments of human hair that involves a washing procedure with acetone and Milli-Q water, microwave digestion with 65% HNO3, and analysis with Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS/MS). Evaluation of preparation steps revealed stainless-steel scissors as a major contamination source. Glass digestion vessels were unsuitable for several elements due to high detection limits and relative standard deviations. The optimised method reduced analytical variability and improved sensitivity compared to published protocols. This validated method enables reproducible multi-elemental analysis in hair, highlights overlooked contamination risks, and is now applied in human biomonitoring studies to strengthen exposure assessment and standardisation efforts.
Keywords: determination of elements, optimization, human biomonitoring
Published in DiRROS: 27.01.2026; Views: 319; Downloads: 206
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3. Human hair certified reference material for total mercury, methylmercury, and trace element analysesAkane Yamakawa, Kimiyo Nagano, Kaoru Onishi, Miyuki Ukachi, Milena Horvat, Adna Alilović Osolin, Polona Klemenčič, Ermira Begu, Marta Jagodic Hudobivnik, Keisuke Uchida, 2025, original scientific article Abstract: The National Institute for Environmental Studies (NIES) developed the NIES CRM No. 13-a, a new certified reference material for human hair, using scalp hair from Asian females. This CRM represents a significant advancement in support of global mercury exposure assessments and offers unparalleled reliability and scope compared with existing materials. We aimed to provide a comprehensive overview of the preparation, certification, and application of NIES CRM No. 13-a. In total, 806 bottles (3 g each) were produced, with thorough homogenization ensured through sieving and blending. Certified values for total mercury (1.06 ± 0.07 mg/kg), methylmercury (0.858 ± 0.075 mg/kg), and key trace elements (arsenic, cadmium, lead, selenium, and zinc) were determined through extensive collaborative analyses involving 20 laboratories. Additional reference values were provided for calcium, magnesium, sodium, sulfur, antimony, barium, copper, iron, and manganese. Rigorous stability and homogeneity assessments demonstrated the stability of the CRM for over 10 years and consistency across sample units, even for challenging elements such as selenium. The CRM also includes information values of stable mercury isotope ratios, reflecting their growing importance as exposure tracers. This enhancement in accuracy and traceability facilitates accurate mercury and trace element assessments in human hair, enabling improved biomonitoring of mercury exposure, dietary studies, toxicological evaluations, human health risk evaluations, and regulatory compliance.
Keywords: metilirano živo srebro, methylmercury, certified reference material
Published in DiRROS: 05.09.2025; Views: 663; Downloads: 309
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