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Measuring the radioactivity of organically bound tritium in environmental samples is difficult. For the past twenty years, many laboratories have been working on the development of reliable tritium measurement methods. In this context, several interlaboratory comparisons have been organised to develop these methods and enable laboratories to compare themselves. However, the trueness of the measurement methods has never been estimated due to the lack of certified reference materials available for use during the analyses. This document presents the production of the first certified reference material for the measurement of organically bound tritium radioactivity in environmental samples.

The accurate and sensitive quantification of hydroxyl radical (·OH) and glucose is necessary for disease diagnosis and health guidance, but still challenging owing to the low concentration of ·OH and poor water solubility of fluorescent probes. In addition, fluorescent probes may cause secondary pollution to the environment. Here an organic cage was reported as a sensitive fluorescent probe for ·OH and glucose in aqueous solution without serious secondary pollution. The prepared organic cage with good water solubility showed specific redox affinity to ·OH in acidic condition, resulting in two oxidation stages of mild oxidation and subsequent oxidative degradation. Fluorescence around 485 nm enhanced remarkably in the first stage, and benzene ring in organic cage was degraded in the second stage. Based on the significant fluorescence enhancement, a sensitive fluorescence turn-on sensing method for ·OH was established within 90 s with the limit of detection (3s/k, where s and k are the standard deviation for 10 replicate detections of blank and the slope of calibration function) of 5 nM. The recoveries of spiked ·OH in human serum and water samples ranged from 95.2 % to 102.7 %. After the glucose oxidase enzyme-Fenton reaction was involved, the ·OH detection was also applied to sensitive sensing of glucose with the limit of detection (3s/k) of 6 nM. The recoveries of spiked glucose in sugary drinks ranged from 96.2 % to 102.6 %. Furthermore, the proposed method would also be suitable for other hazardous substances and biomarkers which can produce hydrogen peroxide and further form ·OH via Fenton reaction.

Analysis of glass-based artworks is important for authentication purposes. In recent years, there have been rapid advancements and improvements in the characterization of glass objects using different analytical approaches. The present study presents an interdisciplinary and multi-analytical authentication approach that provides useful tools and markers to unmask possible imitations, counterfeiting, and forgeries in Cultural Heritage glass beads by comparing the composition of historical and modern glass beads. The approach includes the use of binocular magnifying glass, X-ray Fluorescence (XRF), Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDS), UV-Vis spectrophotometry, X-ray diffraction (XRD) and Laser Induced Breakdown Spectroscopy (LIBS) techniques. Resulting data indicate that antimony, when detected, is only present in historical beads, while boron, zinc, and/or molybdenum are only detected as possible components in modern beads. As marker chromophores for historical beads, lead antimoniate or iron are responsible for yellow, copper for red, and iron and/or copper for green colors. Modern beads coloration was attributed to the presence of cadmium sulfoselenide microparticles for yellow to red colors and chromium for green colors. Opacity in historical beads was generated by dispersed tin oxide or calcium antimoniate microcrystals, while in modern beads the opacity is related to ZrO₂ microcrystals and/or fluorine ions. In this study, LIBS has been validated and proven feasible for in situ exploring analytical parameters that can be useful for authentication purposes of historical glass objects, regardless of their size, provenance, and chronology.

Conventional carbon dots (CDs) typically exhibit substantial variations in fluorescence intensity across different pH. This limitation underscores the pressing need for advancements in their stability and performance under diverse environmental conditions. Herein, l-cysteine and neutral red are selected as precursors, and three kinds of CDs, which can emit red, orange, and green fluorescent light (assigned as r-CD, o-CD, g-CD, respectively), are synthesized by simply changing the reaction conditions. The pH resistance of r-CD and o-CD in acidic and alkaline environments was demonstrated. A fluorescence detection system for natural flavonoid apigenin was established with r-CD, as r-CD exhibited obviously selective quenching of apigenin, without obvious response to other analogs. The linear range of apigenin detection was divided into low concentration at 2.85-30 μmol L^-1 and high concentration at 90-225 μmol L^-1, demonstrating excellent anti-interference ability in complex environments. In addition, the molecularly imprinted polymer containing r-CD (r-CD@MIP) was also prepared by surface molecular imprinting technique. The maximum adsorption capacity for apigenin was 28.39 mg g^-1, and the adsorption equilibrium reached in 90 min. A complete adsorption-fluorescence detection method of apigenin in actual samples was successfully established by using r-CD and r-CD@MIP. The results demonstrated that the developed CDs and detection methods have promising applications in the field of fluorescence sensing and adsorption.

An idea of using ion-exchanger salt containing optically active cations to prepare ion-selective membranes is proposed. Although the presence of an ion-exchanger in the composition of neutral ionophore based sensors is necessary, the choice of available salts for cation-selective sensors preparation, is usually limited to sodium or potassium compounds. In this work we propose application of an alternative salt, using a cation optically active both in absorption and emission mode as a mobile one. Thus, coloured ion-selective membranes can be obtained. This in turn opens new possibilities of monitoring the state of the receptor layer as well as allows direct analytical application of ion-selective membranes in simple optical mode with all benefits related to eliminating the necessity of using reference electrodes. As a model system Nile blue derivative of tetrakis[3,5-bis(trifluoromethyl)phenyl]borate ion-exchanger was prepared and used to obtain potassium or calcium selective sensors. Selective exchange of ions between the membrane and solution, leading to an increase in optical signal of the solution, can be used to quantify the presence of analyte ions. Thus the sensor pretreatment process is becoming a source of analytical information. The applicability of this approach was verified in determining the presence of potassium ions in the vast majority of interfering ions, e.g. present as impurities in the reagent grade calcium chloride. The resulting potassium ions contents was well comparable with values obtained in course of ICP-MS approach.

As an important biological indicator, the abnormity of the lysozyme level is closely related to many diseases. Herein, we devise a novel ratiometric fluorescence aptasensor for lysozyme based on the controllable excimer formation of a perylene probe, N, N'-bis(6-caproic acid)-3,4:9,10-perylene diimide (PDI) induced by cationic silver nanoparticles (Ag NPs). Binding of lysozyme aptamer with multiple phosphate groups to cationic Ag NPs strongly hinders the formation of excimer, yielding intense monomer fluorescence of PDI probe. With the introduction of lysozyme, the adsorption of aptamer on the surface of Ag NPs will be weakened owing to the specific interactions between aptamer and lysozyme, which greatly facilitates the excimer formation of PDI. Based on the monomer-excimer transition triggered by lysozyme, ratiometric fluorescence aptasensor for lysozyme can be established. A good linear relationship between the ratio of monomer intensity to excimer intensity and the logarithm of lysozyme concentration was obtained in the range of 0.25-15 nM, and as few as 0.25 nM lysozyme could be easily detected. Moreover, excellent selectivity for lysozyme detection and satisfactory results in real sample analysis were also achieved. This work provides an innovative platform for the construction of simple, label-free ratiometric fluorescence sensors towards a wide range of analytes based on perylene probe.

Some biomarkers of acute aortic dissection (AAD) can be used for the potential supplementary diagnosis of AAD, such as C-reactive protein (CRP), smooth muscle myosin heavy chain (SmMHC), and D-dimer (D-D). However, the current measurement methods for common markers primarily rely on sophisticated instruments. The operation process is complicated, and the reagents used are expensive. To provide chronic disease monitoring and home self-examination services for potential AAD patients in real time, we developed a smartphone-based multichannel magnetoelastic (ME) immunosensing device to detect protein levels. Our immunosensor reduced the aforementioned restrictions and demonstrated excellent performance for the supplementary diagnosis of AAD. In this paper, we successfully combined the intelligent terminal with the hardware system to sample the resonance frequency shift (RFS) on the multichannel ME immunosensor. According to the target detection objects with their respective antibodies in the immune binding response, multiple experiments were conducted to detect multiple groups of samples, and we found that a CRP concentration, a SmMHC concentration, and a D-D concentration in the range of 0.1-100μg/mL, 1-4ng/mL, and 0.25-5μg/mL were linearly proportional to the RFS of the ME immunosensor, respectively. For CRP, SmMHC, and D-D, the sensitivities were 13.37Hz/μg∙mL^-1, 155.19Hz/ng∙mL^-1, and 332.72Hz/μg∙mL^-1, respectively, and the detection limits were 2.634×10^-3μg/mL, 1.155×10^-2ng/mL, and 3.687×10^-3μg/mL, respectively. The experiments demonstrated that the accuracy and stability of our device were comparable to those of the vector network analyzer (VNA, Calibration instrument).

Combined the electrostatic interaction of the negatively charged gold nanorods (AuNRs) (as acceptor) and Ru(bpy)₃²⁺ (as donor), an electrochemiluminescence resonance energy transfer (ECL-RET) sensor was constructed and applied for the detection of organophosphorus pesticides (OPs). Negatively charged AuNRs were synthesized by modifying AuNRs with polystyrene sulfonate (PSS) firstly, which can bind to Ru(bpy)₃²⁺ through electrostatic interaction so that the luminophore was absorbed by the acceptor, the resonance energy transfer occurred and only low ECL signal had been detected. Thiocholine can be produced by the hydrolysis process of acetylthiocholine (ATCh) with the help of acetylcholinesterase (AChE), which can bond with PSS-modified AuNRs (PSS-AuNRs) through gold-sulfur interaction, this caused the releasing of the adsorbed Ru(bpy)₃²⁺ into the solution and resulting in the restoration of the ECL intensity. However, the activity of AChE was inhibited by OPs, and the recovery process of the ECL signal was thus suppressed as well. In this study, chlorpyrifos was chosen as model target, the results indicated that the correlation between the ECL intensity and the logarithm of chlorpyrifos concentration showed remarkable linearity across 1 ng/mL to 1 mg/mL, achieving a detection limit of 0.51 ng/mL. The proposed system has been utilized for detecting OPs in real samples with satisfied results.

In this work, a novel method of antimony fire assay (Sb-FA) enrichment combined with laser ablation ICP-MS (LA-ICP-MS) for the determination of ultra-trace platinum group elements (PGEs) in geological samples was established. The purification and recycling technology of ultra-clean and high-purity fire assay collector Sb₂O₃ was proposed, in addition, high-purity quartz crucible was developed to replace the usual clay crucible, then the blank values of PGEs were as low as 0.0007-0.0028 ng g^-1 (for 20 g sample). ¹⁹⁰Os isotopic diluent was used as internal standard (IS) and quantitatively added into the fire assay ingredients, and fully mixed and balanced with the PGEs in the real samples by means of high temperature melting, cupellation and horizontal rotation of crucible and dish. Both ¹⁹⁰Os and PGEs in the real sample were pre-concentrated in microgram level Sb granules (100 mg) through Sb-remaining cupellation. After grinding and polishing, ¹⁹⁵Pt, ¹⁰⁵Pd, ¹⁰¹Ru, ¹⁰³Rh, ¹⁹³Ir, total ¹⁸⁹Os and ¹⁹⁰Os enriched in Sb slices were determined by LA-ICP-MS, ¹⁹⁰Os in the internal standard was calculated by isotope dilution equations. The Certified Reference Materials (CRMs) for PGEs were treated by the same procedure to obtain completely matrix matched Sb slices to solve the problem of no internationally recognized uniform PGEs standard materials for LA-ICP-MS determination. Due to the similar distribution trends of different PGEs in Sb slices by LA-ICP-MS imaging, then matrix-matched internal standard calibration strategy was used to reduce the element fractionation effect and improve the determination precision and accuracy of LA-ICP-MS. The laser frequency, energy density, denudation diameter and dwell times were optimized. Under the optimal conditions, empirical coefficient method was used to fit the standard curve and excellent curve fitting of PGEs were obtained with the correlation coefficient between 0.9990 and 0.9999. The method detection limits (LODs) for PGEs ranged from 0.00042 to 0.010 ng g^-1. The established method was successfully applied to analyze real geochemical samples and various matrix Certified Reference Materials (CRMs) domestic and international, the determined values were in good agreement with the results of Sb-FA ICP-MS and the certified values.

In today's society, heavy metal ions and antibiotic contaminants have caused great harm to water systems and human health. In this study, six isostructural lanthanide metal-organic frameworks [Ln(H₃imda)₂(TPA)(H₂O)₂](Tb for CUST-881, Eu for CUST-882, Dy for CUST-883, Er for CUST-884, Nd for CUST-885, Sm for CUST-886) were constructed by selecting terephthalic acid (TPA) and 4,5-Imidazoledicarboxylic acid (H₃imda) and lanthanide metal ions via solvethermal method. Among them, CUST-881 and CUST-882 can selectively detect Fe³⁺, Cr₂O₇^2-, CrO₄², and ceftriaxone sodium (CRO) in water systems and uric acid in urine. CUST-881 shows very low detection limits for these five substances. Furthermore, Principal Component Analysis (PCA) was used to distinguish Fe³⁺, Cr₂O₇^2-, CrO₄^2-, and CRO in water. To our knowledge, this is the first time that they have been able to be simultaneously distinguished. In addition, the possible sensing mechanism was studied through UV-visible spectroscopy, Infrared spectroscopy, and PXRD analysis. Furthermore, the probe also showed satisfactory repeatability and recovery when applied to UA samples that simulated urine. Based on the above results, lanthanide metal-organic frameworks have great potential for practical monitoring of contaminants in water environments.