Reference Materials Research Articles

Development of HEK293T cell reference materials for β-thalassemia genetic testing using prime editing

Abstract Objectives β-thalassemias, caused by mutations in HBB, are hereditary blood disorders that impose a significant global health burden. Detecting these mutations through accurate genetic analysis is essential. This study aimed to create a panel of cell type reference materials for β-thalassemia genetic testing using prime editing (PE), a flexible and precise genomic editing method. Methods PE3 systems were designed to target specific HBB mutations, including single nucleotide variants (SNVs) (−32 (C>A), CD 17 (A>T)), insertions (CD 14/15 (+G), CD 71–72 (+A)), and deletions (CD 31 (−C), CD 41/42 (−TTCT)). HEK293T cells were edited to carry these mutations. Sanger sequencing was performed to confirm the accurate introduction of homozygous and heterozygous mutations. The cell lines were further verified using commercial reverse dot-blot hybridization and melting curve assays. Results We successfully constructed 12 stable HEK293T cell lines carrying the intended homozygous or heterozygous HBB mutations using PE3 systems. No off-target mutations in the HBB were detected by Sanger sequencing in these stable cell lines, even after more than 10 weeks of culturing. Additionally, all target mutations were accurately and consistently detected using two reverse dot-blot hybridization kits and one melting curve assay kit. Conclusions The 12 stable cell lines exhibited accurate and stable HBB mutations, making them valuable reference materials for β-thalassemia genetic testing. PE3 systems show potential for generating a comprehensive panel of HBB mutations, particularly those that are clinically rare.

Brazilian AMS Radiocarbon Laboratory (LAC-UFF) and intercomparison of preliminary results with Sample Preparation Laboratory (LAPA14C – UFBA)

Abstract This study presents the initial results of carbon-14 dating after performing sample preparation and graphite production processes at the Federal University of Bahia (UFBA) in an intercomparison with the same processes performed at the Radiocarbon Laboratory of the Fluminense Federal University (LAC-UFF). Both laboratories are located in Brazil. The accelerator mass spectrometry (AMS) system at LAC-UFF was used for radiocarbon measurements. To verify any possible contamination sources during sample preparation, we initially performed swipe tests at UFBA, which were subsequently processed and the graphite samples were produced at LAC-UFF. After UFBA, several reference materials (IAEA-C1, -C2, -C6, -C9, and OXII standards) were prepared and converted into graphite. In addition, the sample material was first partially prepared at UFF and UFBA and then analyzed with the AMS system at LAC-UFF. Subsamples were prepared for additional measurements of the δ13C composition with an elemental analyzer coupled to an isotope ratio mass spectrometer (EA–IRMS) in LFNA-UFBA to study the isotopic fractionation and yield of the graphitization reaction. The obtained values closely aligned with the reference values, demonstrating reproducibility and quality and indicating minimal contamination during chemical and graphitization processes. In the future, samples from different matrices will be prepared at UFBA for application in paleoenvironmental and archaeological studies.

Structure and Dynamics of Monoclonal Antibody Domains Using Spins, Scattering, and Simulations.

Antibody-based pharmaceuticals are the leading biologic drug platform (> $75B/year).[1] Despite a wealth of information collected on them, there is still a lack of knowledge on their inter-domain structural distributions, which impedes innovation and development. To address this measurement gap, we have developed a new methodology to derive biomolecular structure ensembles from distance distribution measurements via a library of tagged proteins bound to an unlabeled and otherwise unmodified target biologic. We have employed the NIST monoclonal antibody (NISTmAb) reference material as our development platform for use with spin-labeled affinity protein (SLAP) reagents. Using double electron-electron resonance (DEER) spectroscopy, we have determined inter-spin distance distributions in SLAP complexes of both the isolated Fc domain and the intact NISTmAb. Our SLAP reagents offer a general and extendable technology, compatible with any non-isotopically labeled immunoglobulin G class mAb. Integrating molecular simulations with the DEER and solution X-ray scattering measurements, we enable simultaneous determination of structural distributions and dynamics of mAb-based biologics.

Acoustic State Sensing of Subcooled Boiling Heat Transfer on a CuCrZr Surface Using a Deep Neural Network for Divertor Application

In the cooling systems of a nuclear fusion reactor (NFR), anomaly events may occur where the flow of coolant unexpectedly decreases, such as in a loss-of-flow accident (LOFA). From the viewpoint of reactor safety design, ITER should be capable of handling subcooled boiling in coolant duct lines due to a sudden LOFA under severe operating conditions where the reactor’s divertor is under a steady-state massive heat load of 10 MW / m 2 . To detect anomaly events, we performed a proof-of-concept (PoC) experiment and propose a novel method of state sensing of the coolant duct line based on sound emitted from boiling. In the PoC pool boiling experiment, using a hydrophone, we acquired sound from water boiling where the heat transfer surface was made of a divertor alloy [copper-chromium-zirconium (CuCrZr)] or copper (Cu) as the reference material. Notably, microbubble emission boiling (MEB) occurred at the highest heat flux in the case of CuCrZr alloy as well as Cu. This indicates that MEB can also occur in an actual NFR. In this study, we developed deep neural network (DNN) models to identify boiling states from acquired sound. Our well-trained DNN models could distinguish between the boiling sound of Cu and the CuCrZr alloy of the heat transfer surface material. The regression DNN models achieved a coefficient of determination R 2 of approximately 99%. Based on the PoC study, we have demonstrated that DNN models of boiling acoustics have the potential to identify boiling states inside coolant duct lines in the NFR, where the heat flux ranges from the low region to the high region with MEB occurrence.

Research progress in the etiology and minimally invasive therapy of hallux valgus.

Hallux valgus (HV) is the most common foot deformity. It has various pathogenic factors that make its pathogenesis challenging to understand. As the disease progresses, patients experience amplified pain and decreased activities, significantly affecting their quality of life. At present, clinics offer several conservative and surgical treatments that must be selected based on patient condition and disease progression. Surgical treatment is frequently the only method available to patients with HV to delay disease progression and correct the deformity after conservative treatment fails. In recent years, minimally invasive surgical treatments have gained significant attention and developed rapidly due to their well-known advantages, such as safety, efficiency, and quick recovery time. The number of literature that provides a systematic review of the subject must be increased. This review tracks recent advancements, summarizing the etiological mechanism, epidemiology, diagnosis, and treatment of HV. In addition, it emphasizes typical surgical therapies and focuses on the progress of minimally invasive treatment from the first generation to the current fourth generation. This review will serve as a systematic basis for the clinical treatment of HV and provide a reference material for future research.

Certified reference materials for GMO analysis-more than 25 years of GMO CRM production at EC JRC.

Certified reference materials (CRMs) play a crucial role in ensuring the quality of analytical measurements. Particularly, the EU labelling legislation on genetically modified organisms (GMOs) in food and feed products explicitly requires CRMs for its implementation. The CRMs are used to calibrate and control the quantitative real-time polymerase chain reaction (qPCR) method and support official control laboratories, such as National Reference Laboratories (NRLs), in maintaining their ISO/IEC 17025 accreditation. The Joint Research Centre of the European Commission (EC JRC) is specialized in the production of reference materials and has been producing GMO CRMs since 1998. Together with a validated event-specific qPCR method, these GMO CRMs form the EU reference system for the quantification of EU-authorized GMO events in food and feed products and ensure a common GMO labelling threshold. This article gives a retrospective view on the more than 25 years of GMO CRM production at JRC. It describes requirements for GMO CRMs in view of an EU market authorization under (EC) No. 1829/2003. The evolution and major improvements of the production of GMO CRMs at JRC are summarized as well as the current understanding of theEU's GMO reference system for GMO quantification and its impact on commutability. It provides insights into GMO CRM sales and their worldwide distribution. This information may be useful for policymakers and researchers in understanding the current EU GMO measurement landscape and to anticipate possible future demands related to GMO events based on new genomic techniques (NGTs).

BHSeP38 Hernia assessment & management pathway

Abstract The new millennium has brought in so much rapid advancements to the field of hernia that not just surgeons in practice but even training institutes are struggling to keep pace. General Surgeons who primarily have been managing this condition would find it difficult to negotiate the maze of newer terminologies, techniques or complex situations & may end up with less favourable outcomes. In the current state of chaos a training program is acutely needed to empower young surgeons to make better decisions for best outcomes. With these objectives; targeting trainees to surgeons in practice; We have designed a course to streamline the thought process in approaching a hernia patient. It is a comprehensive course encompassing classifications to complications and special scenarios as well. Specific learning objectives defined for each of the topics are in the knowledge and communication domain. Hence the course has been designed around faculty led small group discussions enabling personalised attention to each participant to modulate and enhance their decision making. Unlike other courses it does not restrict to one specific approach or technique but focusses on the entire speciality. The participants are shared reference material to prepare for the course. A pre-test & a post test is conducted to assess the impact of the course. We intend to bring about a positive change by empowering young surgeons to make better decisions which may improve hernia outcomes in the future. We would like to share our experience based on training 50 delegates in multiple sessions.

δ26Mg Values of Thirty‐One Geological Reference Materials Analysed by the Critical Mixture Double Spike Technique

Stable Mg delta values (the relative deviation from a certain reference material, e.g., DSM‐3 here and expressed as δ26MgDSM‐3) were routinely measured by the sample‐standard bracketing (SSB) method on a multi‐collector ICP‐MS, as only three isotopes (i.e., 24Mg, 25Mg and 26Mg) naturally exist. Due to potential inaccuracy in correcting mass bias during measurements, considerable measurement bias has been reported among laboratories. Recently, a critical mixture double spike (CMDS) technique has been developed and demonstrated to accurately correct mass bias of measurement results with precision of ± 0.03‰ for δ26Mg. Here, we measured thirty‐one geological reference materials including igneous, metamorphic and sedimentary rocks, sediments and minerals using the CMDS technique, with the purpose of better characterising their δ26MgDSM‐3 values. Aligning with the data previously reported, uncorrected bias, on average measured by ∆26MgSSB‐CMDS (i.e., δ26MgSSB ‐ δ26MgCMDS) as ‐0.071 ± 0.092‰ (2s, n = 42), has been reaffirmed for the traditional SSB method. Such uncorrected bias positively correlates with sample Mg/(Si+Al+Ca), and thus may result from the accumulative effect of residual matrix elements. The new data set herein can aid future inter‐laboratory comparison and data quality control.

Exposure of Sn-Wetted W CPS Targets to Simultaneous NBI Beam and High-Power CW Laser Pulses at the High-Heat Flux OLMAT Facility

First experiments are reported of the simultaneous exposure of a number of Sn-wetted W CPSs and a reference W CPS to 100 ms NBI pulses (divertor steady-state loading conditions) and 2 ms long high-energy laser pulses (divertor ELM like loading conditions) at the High-Heat Flux OLMAT facility. The use of a fast-frame imaging camera allows monitoring the onset of particle ejection from the targets during laser pulses and obtaining the corresponding laser heat fluxes as a measure of the resilience of these targets. Fast camera images are used also to determine ejected particle numbers and to estimate their maximum velocities as laser power is increased in order to compare the influence of W CPS structure on these parameters. In addition, the craters resulting from particle ejection are studied for each target with an optical microscope and a scanning electron microscope. Moreover, in-situ W and Sn particle ejection is followed using visible emission spectroscopy and post-exposure W melting after particle ejection is observed using the energy dispersive X-ray method EDX for all the studied targets. This shows that Sn is unable to protect the underlying W substrate from high-energy laser damage, albeit a subsequent refilling of the formed craters with Sn is visible during NBI-only pulses after laser damage. Thus, it is considered that optimization of surface refilling/replenishment with Sn is needed to improve the W substrate protection. From this work, it is also found that the W CPS reference material has a higher laser heat flux threshold for particle ejection than the Sn-wetted targets. Nevertheless, it is important to take into account that in these experiments with laser pulses, the possible beneficial effects of vapor shielding that can take place during particle irradiation at ELMs or disruptions are not present, thus these experiments represent a worst-case scenario.

P0270 Standardisation of Rapid TDM Assay with WHO International Reference Material for Anti-Infliximab Antibodies

Abstract Background Point-of-care (POC) tests play a crucial role in therapeutic drug monitoring (TDM) for Inflammatory bowel disease (IBD) patients undergoing anti-TNF therapy. Infliximab (IFX), the first biologic used in IBD treatment, is a chimeric anti-TNF-alpha blocker. However, its composition can trigger an immune response in patients, leading to the production of anti-drug antibodies (ADAs). Consequently, regular monitoring for ADAs is essential during IFX therapy. Various assays are available to measure anti-IFX antibody levels, mainly based on ELISA technology. The recent introduction of an international reference material (IRM) for infliximab ADAs allows enhanced measurement traceability and enables harmonised standardisation and improved comparability across different assays. Furthermore, it is mandatory to standardise with an existing IRM for compliance with the in vitro diagnostic regulation (IVDR). This study focused on standardising the lateral flow based Quantum Blue® Anti-Infliximab assay (LF-ADIF) using the IRM and comparing its performance with the current standardisation material. Additionally, a method comparison to established ELISA assays was carried out. Methods The lateral flow assay was calibrated with both the currently used standardisation material and the new IRM. Blant-Altman analysis was performed to evaluate the comparability of both standardisation materials. To establish the cut-off, 105 healthy donor samples were measured. This cut-off will be used for discrimination of positive and negative results of the rapid test. Furthermore, a set of 30 patient samples was analysed for method comparison with established ELISA assays. Results The Blant-Altman analysis revealed that a IRM based calibration is feasible and IRM concentrations <100 IU/mL can be detected. A technical cut-off was established allowing the discrimination of positive and negative patient samples. Total agreement between the lateral flow assay and the ELISA assays was demonstrated in the method comparison. Conclusion To the best of our knowledge the here presented assay is the first IRM based and IVDR ready lateral flow assay for anti-infliximab. The total agreement of patient sample results between the Quantum Blue® Anti-Infliximab assay and commercially available ELISA assays revealed good comparability. IRM standardisation across all anti-IFX assays would further improve comparability between them.

Glow Discharge Optical Emission Coded Aperture Spectroscopy.

Glow discharge optical emission spectrometry (GDOES) allows fast and simultaneous multielemental analysis directly from solids and depth profiling down to the nanometer scale, which is critical for thin-film (TF) characterization. Nevertheless, operating conditions for the best limits of detection (LODs) are compromised in lieu of the best sputtering crater shapes for depth resolution. In addition, the fast transient signals from ultra-TFs do not permit the optimal sampling statistics of bulk analysis such that LODs are further compromised. Furthermore, commercial GDOES instruments rely on a slit-based light dispersion that favors high spectral resolution at the expense of light throughput. Here, a new technique called glow discharge optical emission coded aperture spectrometry (GOCAS) is shown to allow both a higher spectral resolution and higher light throughput by using a coded aperture (CA) with multiple thin slits at the spectrograph's entrance to measure the convoluted spectra and compressed sensing (CS) algorithms to recover the deconvoluted spectra from the full field of view. The effects of CA characteristics on spectral reconstruction fidelity were studied and showed the best fidelity for smaller slits, 50% transmittance, and wider CA with a higher number of slits. In addition, Shearlet enhanced snapshot compressive imaging (SeSCI)GPU showed the best performance of the CS algorithms studied, including SeSCICPU, two-step iterative shrinkage/thresholding (TwIST), and alternating direction method of multipliers total variation minimization (ADMM-TV). Moreover, GOCAS is shown to be very robust against increasing detector Gaussian noise. Finally, standard reference materials are used to show up to ∼30× improved S/N and an order-of-magnitude improved LODs, at the fastest acquisition times (fraction of a ms), which has the potential to be transformative for depth profiling of nanostructured materials.

A Vacuum Ultraviolet (UV) Photoreactor-Based Flow Droplet Digestion for Determination of Arsenic and Mercury in Blood by Atomic Fluorescence Spectrometry.

It is still challenging to perform a high-throughput digestion on limited amounts of sample prior to elemental analysis by atomic spectrometry. Herein, a photochemical reactor consisting of a quartz tube inserted into a low-pressure mercury lamp was used to fabricate a flow droplet photodigestion (FD-PD) device for the high-throughput digestion of small amounts of samples. A mixture containing 20 μL of blood sample, 20 μL of H2O2, and 10 μL of HNO3 was pumped and passed through the reactor before its online analysis by hydride generation atomic fluorescence spectrometry (HG-AFS). The developed photochemical reactor provides significantly higher oxidation capability than conventional ultraviolet (UV) photochemical reactor since the vacuum UV irradiation below 200 nm from the mercury lamp directly irradiates samples with high transmittance, enabling complete digestion within 2 min. Compared to conventional digestion methods, the proposed method retains several unique advantages of higher sample throughput (57 pcs h-1), lower sample, mineral acid, and oxidant consumption, and shorter digestion time, facilitating painless blood analysis for children. Limits of detection (LODs) of 0.25 and 0.15 μg L-1 were obtained for As and Hg, respectively, with precisions (relative standard deviations (RSDs), n = 11, 2.0 μg L-1) better than 4%. The practicality of FD-PD-HG-AFS was confirmed by detecting As and Hg in one blood and two urine certified reference materials (CRMs), as well as several children's blood samples with satisfactory recoveries (93%-109%).

Species-specific Antimony Isotope Analysis by High Performance Liquid Chromatography Coupled with Multicollector ICPMS Using Hydride Generation as an Interface.

A novel method has been developed for the simultaneous online determination of the isotopic compositions of different antimony (Sb) species in a single analytical run using high-performance liquid chromatography (HPLC) coupled with multicollector inductively coupled plasma mass spectrometry (MC-ICPMS), with hydride generation (HG) serving as the interface. Various parameters affecting the precision of Sb isotope analysis including HG conditions, transient signal processing methods and peak integration windows, were optimized. The linear regression slope method and a 100% peak integration window provided the optimal precision. Under optimized conditions, our method achieved external 2SD precisions better than 0.05‰ for both Sb(III) and Sb(V), with minimal consumption of 0.5 ng for Sb(III) and 5 ng for Sb(V). Furthermore, flow injection (FI) coupled with HG-MC-ICPMS demonstrated precise Sb isotopic analysis with sample requirements as low as 0.25 ng. The proposed methods were validated by analyzing δ123Sb in synthetic solutions and reference materials. Additionally, it was applied to investigate isotopic fractionation during the reduction of Sb(V) by KI, revealing preferential reduction of the light Sb isotope(121Sb). The isotopic compositions of Sb(V) varied from -0.04- 1.18‰, fitting well with a Rayleigh fractionation model and yielding a fractionation factor (αSb(III)-Sb(V)) of 0.99831. In summary, this approach enables high precision isotopic analysis of Sb(III) and Sb(V) simultaneously with reduced sample consumption, providing a powerful tool for investigating Sb isotopic fractionation in various environmental processes and advancing our understanding of the Sb biogeochemical cycle.

Land policy and land reforms in 1990-2024 taking into account the orders of the President of the Russian Federation V.V. Putin made on 18.04.2024 based on the results of the visit to Stavropol Krai on 5 March 2024

On May 11, 2012, the Committee on World Food Security (CFS) of the Food and Agriculture Organization of the United Nations approved the Guidelines on "Responsible Governance of Tenure of Land, Fisheries and Forests in the Context of National Food Security." These guidelines serve as a reference material and provide recommendations for improving resource management to ensure food security. The management of tenure and resource use systems is a key element in determining the rights and obligations of users. Ineffective management leads to social instability, environmental problems, economic losses, and conflicts due to corruption or the inability of authorities to protect people's rights. Responsible management, on the other hand, promotes sustainable social and economic development and creates favorable conditions for investment.

Trams: Bridging the Past and Future—Example Guidelines for Tram Redesign Illustrated by a Case Study from Korea

This study was inspired by an emerging trend in contemporary cities: the transformation of trams into mobile spaces for recreation, education, and work. Despite the growing popularity of this concept, which is linked to the search for more sustainable transport options, there is a marked lack of guidelines, methodological frameworks, and reference case studies necessary to support these projects. This study fills this gap by illustrating the design guidelines developed for a project in Gwangmyeong, a new Korean town. These guidelines provide a structured framework for converting existing trams into mobile venues such as restaurants, classrooms, and work and conference spaces. Employing the design thinking approach, the guidelines comprise three primary design phases—Understand, Define, and Materialize—each consisting of two sub-phases, and specify the technical tools, roles, and outputs needed. The proposed guidelines are illustrated using material from the Gwangmyeong project. As the first of their kind, these guidelines provide a valuable case study and reference materials for designers, offering possible benchmarks for the technical and financial evaluation of such projects. This study hopes to stimulate discussions on the development and refinement of similar methodologies, addressing the growing interest in design discourse.

Application of predictive modeling tools for the identification of Ocimum spp. herbal products.

Species identification of botanical products is a crucial aspect of research and regulatory compliance; however, botanical classification can be difficult, especially for morphologically similar species with overlapping genetic and metabolomic markers, like those in the genus Ocimum. Untargeted LC-MS metabolomics coupled with multivariate predictive modeling provides a potential avenue for improving herbal identity investigations, but the current dearth of reference materials for many botanicals limits the applicability of these approaches. This study investigated the potential of using greenhouse-grown authentic Ocimum to build predictive models for classifying commercially available Ocimum products. We found that three species, O. tenuiflorum, O. gratissimum, and O. basilicum, were chemically distinct based on their untargeted UPLC-MS/MS profiles when grown in controlled settings; combined with an orthogonal high-performance thin-layer chromatography (HPTLC) approach, O. tenuiflorum materials revealed two distinct chemotypes which could confound analysis. Three predictive models (partial least squares, LASSO regression, and random forest) were employed to extrapolate these findings to commercially available products; however, the controlled materials were significantly different from external samples, and all three chemometric models were unreliable in classifying external materials. LASSO was the most successful when classifying new greenhouse samples. Overall, this study highlights how growing and processing conditions can influence the complexity of botanical metabolome profiles; further studies are needed to characterize the factors driving herbal products' phytochemistry in conjunction with chemometric predictive modeling.

Robust discrimination between closely related species of salmon based on DNA fragments.

Closely related species of Salmonidae, including Pacific and Atlantic salmon, can be distinguished from one another based on nucleotide sequences from the cytochrome c oxidase sub-unit 1 mitochondrial gene (COI), using ensembles of fragments aligned to genetic barcodes that serve as digital proxies for the relevant species. This is accomplished by exploiting both the nucleotide sequences and their quality scores recorded in a FASTQ file obtained via Next Generation (NextGen) Sequencing of mitochondrial DNA extracted from Coho salmon caught with hook and line in the Gulf of Alaska. The alignment is done using MUSCLE (Muscle 5.2) (Edgar in Nat Commun 13:6968, 2022), applied to multiple versions of each fragment perturbed according to the nucleobase identification error probabilities underlying the quality scores. The Damerau-Levenshtein distance was used to determine the genetic barcode of the candidate species that is closest to each aligned, perturbed fragment. The "votes" that the sampled fragments cast for the different candidate species are then pooled and converted into identification probabilities, using weights determined by the entropy of the fragment-specific identification probability distributions. This novel approach to quantify the uncertainty associated with measurements made using NextGen Sequencing can be applied to discriminate closely related species, hence to value-assignment for reference materials supporting determinations of the authenticity of seafood, for example, NIST Reference Materials 8256 and 8257 (Coho salmon) (Ellisor et al., 2021).

Comparison of different characterization approaches for monoelemental calibration solutions at two national metrology institutes.

Monoelemental calibration solutions are the most common reference in elemental analysis, linking measurement results to the International System of Units (SI). National Metrology Institutes (NMI) prepare these solutions as certified reference materials (CRM) and determine their elemental mass fraction with high accuracy. Characterization with high accuracy is one of the most critical steps in CRM production. This report compares the approaches taken by the NMIs of Türkiye (TÜBİTAK-UME) and Colombia (INM(CO)) in preparing and characterizing cadmium calibration solutions with a nominal value of 1 g kg-1. Each NMI produced CRMs using an independent batch of cadmium calibration solution and assigned mass fraction values to both their own solutions and those of the other NMIs. TÜBİTAK-UME employed a primary difference method (PDM) to assess the purity of a cadmium metal standard, quantifying all possible impurities using a combination of instrumental analytical techniques. The defined purity standard was used for both the gravimetric preparation of the CRM and the calibration of high-performance inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. On the other hand, INM(CO) used gravimetric titration with EDTA to assay cadmium in the CRM solutions. The EDTA salt was previously characterized by titrimetry. Despite the fundamentally different measurement methods and independent metrological traceability paths to the SI, the measurement results exhibited excellent agreement within the stated uncertainties. This comparative analysis demonstrates the effectiveness of varied characterization approaches and underscores the reliability of the cadmium calibration solutions prepared by TÜBİTAK-UME and INM(CO). This collaborative effort highlights the reliability and adaptability of various measurement techniques in fulfilling rigorous metrological standards for elemental calibration solutions. Furthermore, this approach enhances the robustness of the measurements in the field of elemental analysis and contributes traceability to the SI.

Study of Ultrasound-Assisted Low-Pressure Closed Acid Digestion Method for Trace Element Determination in Rock Samples by Inductively Coupled Plasma Mass Spectrometry.

In this paper, a method of ultrasound-assisted low-pressure closed acid digestion followed by inductively coupled plasma mass spectrometry (ICP-MS) analysis was proposed for trace element quantification in rock samples. By using 1.5 mL of a binary acid mixture of HNO3-HF with a ratio of 2:1, rock powder samples of 50 mg were completely decomposed in 12 h at 140 °C after 4 h of ultrasonic treatment with or without pressure relief procedure. The element extraction efficiency of this method was evaluated via the yielded relative errors (REs) of the trace elements in a series of geological standard reference materials (SRMs) with compositions from basic to acidic. It was found that the contents of trace elements (i.e., 36 metal elements from Li to U) in basalt BCR-2, diabase W-2a, andesite AGV-2, granodiorite GSP-2, and granite GSR-1 were comparable with the reported reference values, giving REs with absolute values less than 10%. It was also found that clear solutions without sample powder residues by naked-eye observation can be obtained when using the low-pressure closed decomposition method without ultrasonic pretreatment. The quantification results, however, were found to be negatively biased for most of the studied trace elements, and, in particular, the content bias of Zr in SRM GSP-2 was down to -86.28% due to the low extraction efficiency of refractory minerals of the low-pressure closed digestion method. By applying this proposed digestion strategy, the decomposition property of the ternary combination of HNO3-HF-mannitol in terms of trace element quantification accuracy was also investigated. Results showed that the concentrations of trace elements in the studied SRMs were consistent with the reference values, giving REs within ±6.94%, which revealed that there was no deterioration of extraction efficiencies of trace elements and neglected mass interferences from mannitol. This study demonstrated the essential role of ultrasound irradiation in rock sample decomposition to achieve the high extraction efficiency of trace elements under a low-pressure environment, and the developed approach with promising future applications in geoscience exhibited considerable merits, including a high extraction efficiency, feasible digestion process, less time consumption, and lower safety associated risks.

Ultrasound-Assisted Extraction Followed by Inductively Coupled Plasma Mass Spectrometry and Multivariate Profiling of Rare Earth Elements in Coffee.

A rapid and efficient ultrasound-assisted extraction (UAE) procedure followed by inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of 14 rare earth elements (REEs) (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), along with yttrium (Y) and scandium (Sc), in coffee samples. The method was validated using certified reference material (NIST SRM 1547), recovery tests at four fortification levels, and comparisons with microwave-assisted digestion (MAD). Excellent accuracy and precision were achieved, with recovery rates ranging from 80.1% to 112% and relative standard deviations (RSD%) below 14%. Limits of detection (LODs) ranged from 0.2 ng/kg (Yb) to 0.16 µg/kg (Nd). Total REE concentrations varied between 8.3 µg/kg and 1.1 mg/kg, with the highest individual mean concentrations (µg/kg) observed for Ce (11.7), La (6.0), and Sc (4.7). The lowest individual mean concentrations (µg/kg) were for Ho (0.16), Lu (0.066), and Tm (0.063). Multivariate analysis of REE profiles from 92 coffee samples collected in Serbia revealed clear distinctions between ground roasted and instant coffees, as well as between different surrogate blends. This study indicated that the determination of coffee's geographical origin was not possible due to the diverse types, blends, and additives. However, differences in REE profiles suggest potential classification based on variety. REEs pose a negligible health risk to coffee consumers, with HI values ranging from 4.7 × 10-8 to 6.3 × 10-6 and TCR ranging from 2.6 × 10-14 to 3.5 × 10-12.