Fluorescence Spectroscopy Research Articles

Utilization of Natural Adsorbents in the Purification of Used Sunflower and Palm Cooking Oils

The purification of used oils and their introduction into production cycles lead to reduction in environmental contamination. A simulation was conducted to study the thermal degradation of sunflower oil under varying temperatures over time. In the purification process of used cooking oil, an adsorption technique using zeolite and eggshell as an adsorbent (5, 10, 20, and 30 g/100 mL used oil) was applied. To optimize purification, different doses of thermally and chemically activated adsorbents were used, at different temperatures (30 and 80 °C). Therefore, this study was conducted in batch operations to determine the effect of suitable adsorption for a contact time of the adsorbent of 2 h. In comparison, the purification of used vegetable oils was achieved using a saline solution. The adsorption capacity was evaluated by determining the physicochemical parameters of the oils before and after purification. The characterization of natural adsorbents was carried out using scanning electron microscopy (SEM) and X-ray fluorescence spectrometry (XRF). The results showed that the adsorbent in a dose of 30 g of zeolite activated with NaOH and heat-treated eggshell, respectively, exhibited a larger surface area and greater adsorption capacity. Adsorption increased with contact time. The FT-IR spectra of the oils showed the IR bands at 1097, 1160, and 1237, corresponding to the presence of the ester C-O-, 1743 for C=O ester, 2853, 2922 for (CH2, CH3), and 3008 for (C=C). The acidity and peroxide values decreased with increasing dose and contact time with zeolite or eggshell. Together, our result strongly suggests that natural adsorbents contribute to the purification of used oils.

Differentiating Nylon Samples with Visually Indistinguishable Fluorescence Using Principal Component Analysis and Common Dimension Partial Least Squares Linear Discriminant Analysis with Synchronous Fluorescence Spectroscopy.

Fluorescence spectroscopy is an attractive candidate for analyzing samples of nylon. Impurities within the polymers formed during the synthesis and processing of nylons give rise to the observed fluorescence, allowing for nylons to be analyzed based on their impurities. Nylons from the same source are expected to display similar fluorescence profiles, and nylons with different fluorescence are expected to be from different sources. This paper investigates an important case where different nylons displayed similar fluorescence, preventing easy discrimination. Samples of Nylon 6 and Nylon 6/12 had visually indistinguishable excitation-emission matrices (EEM), excitation spectra, fluorescence spectra, and synchronous fluorescence spectra at larger Δλ. By collecting synchronous fluorescence spectra at smaller Δλ, additional features in the fluorescence profiles were identified that allowed for some discrimination between the two nylons. Combining the EEM and synchronous fluorescence data with chemometric algorithms provided a clearer differentiation between the two nylons. parallel factor analysis, principal component analysis, and common dimension partial least squares (ComDim-PLS) showed two distinct clusters in the data, with ComDim-PLS providing the greatest distinction between the clusters. The loadings revealed the variables of interest to the ComDim-PLS were the 400 nm and 335 nm bands for all synchronous fluorescence spectra, the 460 nm and 310 nm bands for the Δλ = 20 nm and Δλ = 30 nm synchronous fluorescence spectra, and the 440 nm band for the Δλ = 20 nm synchronous fluorescence spectra. The linear discriminant analysis performed with the PLS data yielded a classification accuracy of 95% with the EEM data and 100% with the synchronous fluorescence data, displaying the power of this technique to differentiate two different nylons with visually indistinguishable fluorescence spectra.

Synthesis and Photophysical Properties of a Chiral Carbon Nanoring Containing Rubicene.

Herein we report the construction of an inherently chiral carbon nanoring, cyclo[7]paraphenylene-2,9-rubicene ([7]CPPRu2,9), by combining rubicene with a C-shaped synthon through the Suzuki-Miyaura coupling reaction. The structure was fully confirmed by high-resolution mass spectroscopies (HR-MS) and various NMR techniques. The photophysical properties were investigated by UV-vis absorption and fluorescence spectroscopy as well as the time-resolved fluorescence decay. Moreover, two enantiomers (M)/(P)-[7]CPPRu2,9 were successfully resolved by recyclable HPLC and studied by CD and CPL spectra.

Leaching kinetics of ash impurities from aphanitic graphite by combining dual-ultrasound and hydrochloric acid–potassium hydrogen fluoride

The hydrochloric acid-fluoride salt is useful for purifying graphite. Ultrasonic-assisted technique can significantly reduce the leaching time and improve the leaching efficiency. Compared with single-frequency, dual-frequency ultrasound has the advantages of high energy efficiency and wide cavitation area. In this study, the combination of a dual-frequency ultrasound-assisted technique and hydrochloric acid–potassium hydrogen fluoride leaching agent was proposed for the leaching of aphanitic graphite to remove impurity minerals. First, the effects of probe-type ultrasonic power, tank-type ultrasonic power, temperature, HCl concentration, ultrasonication time, and KHF2 concentration on the purification efficiency of impurities from aphanitic graphite with the assistance of dual-frequency ultrasound were investigated. It was found that the combination of dual-frequency ultrasound and hydrochloric acid–potassium hydrogen fluoride can reduce the ash content of aphanitic graphite from 13.02 % to 1.02 % with an ash removal rate of 94.17 %. Second, volumetric reaction models and unreacted shrinkage nucleation models were used to fit the kinetics of impurities from aphanitic graphite with dual-frequency ultrasound-assisted HCl-KHF2 leaching. Kinetic analysis shows that the volumetric reaction model with chemical control was better to fit the leaching process. This is consistent with the calculation results of the activation energy of the reaction (Ea = 58.13 kJ/mol). Finally, laser particle size analyzer, X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray fluorescence spectroscopy (XRF), transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS) were used to analyze the fugacity of impurity minerals during the process of dual-frequency ultrasound-assisted HCl-KHF2 leaching. It was revealed that combining ultrasonic cavitation fragmentation with chloric acid–potassium fluoride generated SiF4 with high solubility, thereby removing silica-bearing impurities more efficiently. The challenges in further reducing ash content from 1.02 % in the leached concentrate of aphanitic graphite could be attributed to the existence of titanium-bearing mineral impurities on the surface of graphite particles and the presence of silica-bearing minerals between graphite carbon layers.

Hybrid Nanoparticles from Random Polyelectrolytes and Carbon Dots.

The present study concerns the preparation of hybrid nanostructures composed of carbon dots (CDs) synthesized in our lab and a double-hydrophilic poly(2-dimethylaminoethyl methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate) (P(DMAEMA-co-OEGMA)) random copolymer through electrostatic interactions between the negatively charged CDs and the positively charged DMAEMA segments of the copolymer. The synthesis of P(DMAEMA-co-OEGMA) copolymer was conducted through RAFT polymerization. Furthermore, the copolymer was converted into a strong cationic random polyelectrolyte through quaternization of the amine groups of DMAEMA segments with methyl iodide (CH3I), and it was subsequently utilized for the complexation with the carbon dots. The molecular, physicochemical, and photophysical characterization of the aqueous solution of the copolymers and their hybrid nanoparticles was conducted using dynamic and electrophoretic light scattering (DLS, ELS) and spectroscopic techniques, such as UV-Vis, fluorescence (FS), and FT-IR spectroscopy. In addition, studies of their aqueous solution using DLS and ELS showed their responsiveness to external stimuli (pH, temperature, ionic strength). Finally, the interaction of selected hybrid nanoparticles with iron (III) ions was confirmed through FS spectroscopy, demonstrating their potential application for heavy metal ions sensing.

Cellular Impact and Biodegradability of S‐ and N‐Doped Graphene Quantum Dots on Human Monocytes and Macrophages

AbstractGraphene quantum dots (GQDs), small graphene domains with lateral dimensions lower than 10 nm, are increasingly used in electronics, composites, and biomedicine. Chemical doping of GQDs allows tuning their optical properties. Immune cells are among the first cells exposed to nanomaterials entering a living body, rapidly triggering a downstream immune response. However, the assessment of the impact of chemically‐doped GQDs on the immune system remains rather limited if not absent. In this context, the effects and the biodegradability of sulfur‐doped and nitrogen‐doped GQDs (S‐GQDs and N‐GQDs) on human monocytes and macrophages are evaluated. The metabolic activity, membrane integrity, apoptosis, and intracellular reactive oxygen species (ROS) generation are studied. In parallel, the degradation of GQDs using human myeloperoxidase and a peroxynitrite‐mediated system is investigated in test tube. Their degradation in macrophages is also pursued. High‐resolution transmission electron microscopy (HRTEM), fluorescence spectroscopy, Raman, and flow cytometry are used to confirm the degradation. Overall, both GQDs exert little activation on monocytes and macrophages although they decrease the metabolic viability in a dose‐dependent manner. The loss of native GQD structure and crystal lattice provide evidence of their biodegradability. Both the safety and biodegradability of S‐GQDs and N‐GQDs ensure their potential in biomedical applications.

Wear Resistance Behavior of Low-, Mid-, and High-Phosphorus Electroless Ni-P Coatings Heat-Treated in the Air Environment

The high-temperature heat treatment of electroless nickel–phosphorus (Ni-P) coatings in an air environment, and its consequences have scarcely been investigated. This work investigated tribological characteristics of the high-temperature, heat-treated, electroless Ni-P coatings on steel substrates with low-, mid-, and high-phosphorus content for which the average phosphorus content was 2.4 wt.%, 7.1 wt.%, and 10.3 wt.%, respectively. X-ray fluorescence and energy dispersive spectroscopy were implemented to determine the phosphorus content of the coatings. The oxidation of Ni and the formation of the NiO layer on the coating surface was confirmed by the X-ray diffraction technique. A reciprocating sliding method on a ball-on-flat system was utilized to evaluate the coating’s friction and wear behavior. Among the coatings with varying phosphorus content, a high hardness of 1086 HV was found for high-phosphorus coating when heat-treated at 400 °C in an air environment, and that was decreased to 691 HV when heat-treated at 650 °C. The oxidation of nickel in the electroless Ni-P coating occurred when heat-treated at 400 °C in an air environment, and this phenomenon was increased more when the temperature was increased to 650 °C. The characteristics of the NiO layer that formed on the surface of the heat-treated electroless Ni-P coating were influenced by the concentration of phosphorus, which caused different colors of NiO to be seen on the Ni-P coating surface. A greenish black NiO layer on the low-phosphorus and black NiO layer on the mid- and high-phosphorus Ni-P coating was developed during heat treatment at 650 °C in an air atmosphere. The adhesion and tribological characteristics of the Ni-P coatings were affected by the NiO layer developed on the heat-treated Ni-P coating surfaces. The Ni-P coatings with mid- and high-phosphorus content showed enhanced wear-resistance characteristics when they underwent heat treatment in an air atmosphere at the high temperature of 650 °C. The wear volume obtained for as-plated mid-phosphorus and high-phosphorus Ni-P coatings was 0.111 mm3 and 0.128 mm3, respectively, and that was reduced to 0.031 mm3 and 0.051 mm3, respectively, after the high-temperature heat treatment.

Printing and imprinting the Missale Nidrosiense: a multidisciplinary investigation of the first printed book of Norway

In our study, we employed an interdisciplinary approach to study the diverse parts of the Missale Nidrosiense, published in 1519. Our aim was a thorough investigation of the materials used and the manufacturing methods that may give indications on dating and provenance of the components of the book and where the book was bound. Initially, visual and multispectral methods were employed to investigate the books’ components, printing technology and bookbinding structure. Subsequently, other methods were applied: the composition of metallic components was determined by X-ray fluorescence spectroscopy (XRF). Pigments, printing inks and binders were characterised by using a combination of XRF and synchrotron-based infrared microscopy. Non-invasive dendrochronology based on X-ray tomography was utilised, to indicate date and provenance of the wooden boards of the book. Additionally, we used a biocodicological approach to identify the species of animal used in the parchment. This resulted in a complete biography of the book. We were able to acquire new information about the materials used and their provenance. This provides new information about craft, economy, trade and commercial exchange in the beginning of the sixteenth century in North-west Scandinavia, despite the lack of written documentation from this period.

Hectorite/Phenanthroline-Based Nanomaterial as Fluorescent Sensor for Zn Ion Detection: A Theoretical and Experimental Study

The development of fluorescent materials that can act as sensors for the determination of metal ions in biological fluids is important since they show, among others, high sensitivity and specificity. However, most of the molecules that are used for these purposes possess a very low solubility in aqueous media, and, thus, it is necessary to adopt some derivation strategies. Clay minerals, for example, hectorite, as natural materials, are biocompatible and available in large amounts at a very low cost that have been extensively used as carrier systems for the delivery of different hydrophobic species. In the present work, we report the synthesis and characterization of a hectorite/phenanthroline nanomaterial as a potential fluorescent sensor for Zn ion detection in water. The interaction of phenanthroline with the Ht interlaminar space was thoroughly investigated, via both theoretical and experimental studies (i.e., thermogravimetry, FT-IR, UV-vis and fluorescence spectroscopies and XRD measurements), while its morphology was imaged by scanning electron microscopy. Afterwards, the possibility to use it as sensor for the detection of Zn2+ ions, in comparison to other metal ions, was investigated through fluorescent measurements, and the stability of the solid Ht/Phe/Zn complex was assessed by different experimental and theoretical measurements.

Cd(II)-based complex loaded with drug doxorubicin hydrogels against leukemia and reinforcement learning

A new 3D metal–organic frameworks [Cd6(L)4(bipy)3(H2O)2·H2O] (1) was gained by employing Cd(II) and organic ligand [H3L = 4,4′,4′′-(benzene-1,3,5-triyltris(oxy))tribenzoic acid)benzene acid; bipy = 4,4′-bipyridine] in the solvothermal condition, which has been fully examined via single-X ray diffraction, FTIR and elemental analysis and so on. Using natural polysaccharides hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) as raw materials, we successfully prepared HA/CMCS hydrogels and observed their internal micromorphology by scanning electron microscopy. Using doxorubicin (Dox) as a drug model, we synthesized a novel metal gel particle loaded with doxorubicin, and their encapsulation and release effects were studied using fluorescence spectroscopy, followed by further investigation of their components through thermogravimetric analysis. Based on this, the therapeutic effect on leukemia was evaluated. Finally, an enhanced learning method for automatically designing new ligand structures from host ligands was proposed. Through generative modeling and molecular docking simulations, the biological behavior of the host and predicted cadmium complexes was extensively studied.

Molecular Orientation Behavior of Lyotropic Liquid Crystal-Carbon Dot Hybrids in Microfluidic Confinement.

Lyotropic liquid crystals represent an important class of anisotropic colloid systems. Their integration with optically active nanoparticles can provide us with responsive luminescent media that offer new fundamental and applied solutions for biomedicine. This paper analyzes the molecular-level behavior of such composites represented by tetraethylene glycol monododecyl ether and nanoscale carbon dots in microfluidic channels. Microfluidic confinement allows for simultaneously applying multiple factors, such as flow dynamics, wall effects, and temperature, for the precise control of the molecular arrangement in such composites and their resulting optical properties. The microfluidic behavior of composites was characterized by a set of analytical and modeling tools such as polarized and fluorescent microscopy, dynamic light scattering, and fluorescent spectroscopy, as well as image processing in Matlab. The composites were shown to form tunable anisotropic intermolecular structures in microchannels with several levels of molecular ordering. A predominant lamellar structure of the composites was found to undergo additional ordering with respect to the microchannel axis and walls. Such an alignment was controlled by applying shear and temperature factors to the microfluidic environment. The revealed molecular behavior of the composite may contribute to the synthesis of hybrid organized media capable of polarized luminescence for on-chip diagnostics and biomimetics.

Seventeenth-Century Barniz de Pasto Objects from the Collection of the Hispanic Society Museum & Library: Materiality and Technology

The Hispanic Society Museum & Library (HSML) holds a collection of nine viceregal barniz de Pasto objects, made by Indigenous artisans in the 17th and 18th centuries. Designed to imitate Asian lacquers and intended for European aesthetic tastes, barniz de Pasto is an example of Indigenous technique and knowledge that has survived to the present day. An in-depth analysis of five of these barniz de Pasto objects, dated to the first half and last quarter of the 17th century based on their iconography, was carried out through a combination of non-invasive and micro-invasive techniques, including portable X-ray fluorescence (pXRF) spectroscopy to investigate the possible presence of inorganic pigments, and fiber-optics reflectance spectroscopy (FORS) and reflectance imaging spectroscopy (RIS) to provide molecular information on colorants and their distributions across the objects. Dyes and pigments were also identified using Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and liquid chromatography/mass spectrometry (LC/MS). The nature of the resin was determined by FTIR and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), while the decoration stratigraphy and composition were analyzed by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). This paper confirms the use of mopa mopa, the resin used in the barniz de Pasto technique, in two objects not previously analyzed, and identifies indigo, insect-based red, calomel, lead white, and an unknown flavonol-based yellow dye, and challenges the use of calomel as a temporal marker for these works. Taken together, these results expand our understanding of the material use and explorations undertaken by artists during this time period to create such elaborate and enduring objects.

Sasanian Niello Inlay: Microanalytical Investigation of a Silver Oval Bowl with Tigers and Grapevines

ABSTRACT Researchers utilized non-invasive analytical techniques such as micro-X-ray fluorescence (µ-XRF) spectroscopy, micro-X-ray diffraction (µ-XRD), and micro-Raman spectroscopy to examine a silver oval bowl adorned with tigers and grapevines, believed to date back to the Sasanian period of Iran (third to seventh centuries CE). The bowl, currently housed in the Department of Ancient Near Eastern Art at the Metropolitan Museum of Art, underwent analysis aimed at identifying the composition of both the silver alloy and the niello used in its decoration. The primary objective of the study was to discern the alloy composition and the niello application technique employed by Sasanian metalworkers. The findings revealed that the bowl is crafted from a silver–copper alloy containing approximately 3 wt.% of copper. Additionally, the niello inlays were determined to consist solely of silver sulfide (acanthite). The composition of the niello closely resembles that of early Roman niello inlays, suggesting a possible technological connection with Romans in the Sasanian period.

Characterization and immunogenicity assessment of MERS-CoV pre-fusion spike trimeric oligomers as vaccine immunogen

ABSTRACT Middle East respiratory syndrome coronavirus (MERS-CoV) is a lethal beta-coronavirus that emerged in 2012. The virus is part of the WHO blueprint priority list with a concerning fatality rate of 35%. Scientific efforts are ongoing for the development of vaccines, anti-viral and biotherapeutics, which are majorly directed toward the structural spike protein. However, the ongoing effort is challenging due to conformational instability of the spike protein and the evasion strategy posed by the MERS-CoV. In this study, we have expressed and purified the MERS-CoV pre-fusion spike protein in the Expi293F mammalian expression system. The purified protein was extensively characterized for its biochemical and biophysical properties. Thermal stability analysis showed a melting temperature of 58°C and the protein resisted major structural changes at elevated temperature as revealed by fluorescence spectroscopy and circular dichroism. Immunological assessment of the MERS-CoV spike immunogen in BALB/c mice with AddaVaxTM and Imject alum adjuvants showed elicitation of high titer antibody responses but a more balanced Th1/Th2 response with AddaVaxTM squalene like adjuvant. Together, our results suggest the formation of higher-order trimeric pre-fusion MERS-CoV spike proteins, which were able to induce robust immune responses. The comprehensive characterization of MERS-CoV spike protein warrants a better understanding of MERS spike protein and future vaccine development efforts.

Absorption Correction for 3D Elemental Distributions of Dental Composite Materials Using Laboratory Confocal Micro-X-ray Fluorescence Spectroscopy.

Confocal micro-X-ray fluorescence (micro-XRF) spectroscopy facilitates three-dimensional (3D) elemental imaging of heterogeneous samples in the micrometer range. Laboratory setups using X-ray tube excitation render the method accessible for diverse research fields but interpretation of results and quantification remain challenging. The attenuation of X-rays in composites depends on the photon energy as well as on the composition and density of the material. For confocal micro-XRF, attenuation severely impacts elemental distribution information, as the signal from deeper layers is distorted by superficial layers. Absorption correction and quantification of fluorescence measurements in heterogeneous composite samples have so far not been reported. Here, an absorption correction approach for confocal micro-XRF combining density information from microcomputed tomography (micro-CT) data with laboratory X-ray absorption spectroscopy (XAS) and synchrotron transmission measurements is presented. The energy dependency of the probing volume is considered during the correction. The methodology is demonstrated on a model composite sample consisting of a bovine tooth with a clinically used restoration material.

Preserved structure and function of human serum albumin self-folded in the oxidative cytoplasm of Escherichia coli

Human serum albumin (HSA), a polypeptide featuring 17 disulfide bonds, acts as a crucial transport protein in human blood plasma. Its extended circulation half-life, mediated by FcRn (neonatal Fc receptor)-facilitated recycling, positions HSA as an excellent carrier for long-acting drug delivery. However, the conventional method of obtaining HSA from human blood faces limitations due to availability and potential contamination risks, such as blood-borne diseases. This study introduced SHuffle, an oxidative Escherichia coli (E. coli) expression system, for the production of recombinant HSA (rHSA) that spontaneously self-folds into its native conformation. This system ensures precise disulfide bond formation and correct folding of cysteine-rich rHSA, eliminating the need for chaperone co-expression or domain fusion of a folding enhancer. The purified rHSA underwent thorough physicochemical characterization, including mass spectrometry, circular dichroism spectroscopy, intrinsic fluorescence spectroscopy, esterase-like activity assay, and size exclusion chromatography, to assess critical quality attributes. Importantly, rHSA maintained native binding affinity to FcRn and the albumin-binding domain. Collectively, our analyses demonstrated a high comparability between rHSA and plasma-derived HSA. The expression of rHSA in E. coli with an oxidizing cytosol provides a secure and cost-effective approach, enhancing the potential of rHSA for diverse medical applications.

Formulation of Chicken Sausages Enriched with Clove (Syzygium Aromaticum) Powder and Sesame (Sesamum Indicum L.) Flour during the Fermentation Stage

The study evaluated the combined effect of clove and sesame flour during the fermentation stage. The impact of the incorporation of sesame flour in S1 batch (sausages with 80% chicken filet, 17% veal fat, 2% sesame flour, and 1% cloves) and S2 batch (sausages with 80% chicken filet, 16% veal fat and 2% sesame flour, and 2% cloves) compared to Control batch (80% chicken filet, 18% veal fat, and 2% sesame flour) on the physico-chemical, color and molecular structure during the fermentation stage. Results showed that the incorporation of clove in the chicken dry sausages significantly increased the moisture and protein contents since it passed from 14.82 on day 1 in the Control at 30.23 ± 0.90% for S2 on day 1, respectively. The results obtained also showed that clove is a source of antioxidants, since the oxidation indicator parameters decreased with the level of addition of clove. The results demonstrated the potential of using fluorescence spectroscopy for monitoring the quality of sausages, since principal component analysis and factorial discriminant analysis (applied to fluorescence spectra allowed to discriminate between samples according to the level of clove addition (97.22% of correct classification).

In-situ X-ray Fluorescence Analysis of In-plane Cerium-ion Distribution Under Humidity Gradients in Proton Exchange Membrane

Cerium ions are incorporated into proton exchange membranes (PEMs) of fuel cells to mitigate its chemical degradation caused by radical species. However, under fuel cell operating conditions, cerium ions move in in-plane direction in the cell by humidity gradient. This cerium ion transport results in cerium ion depletion leading to accelerated chemical degradation. This study developed an in-situ and operando measurement technique utilizing synchrotron high-energy X-ray fluorescence spectroscopy to monitor the cerium ion transport across the membrane under the in-plane humidity gradient. This method effectively tracks the dynamic behavior of cerium ions under fuel cell operating conditions.

Development of New Series of Certified Reference Materials for Ferrosilicon Magnesium Alloys

This paper presents a practical approach to the production of certified reference materials (CRMs) for ferrosilicon magnesium alloys. These new CRMs are predicted to be used in fast X-ray fluorescence spectrometry (XRF) analysis, which does not require sample digestion and does not result in the production of acidic sewage and emissions, contrary to the classical and instrumental techniques currently used in laboratories. Four new certified reference materials (CRMs) were developed to fill the gap in the reference materials market and ensure fast and traceable analyses. The materials were produced with an industrial process and then homogenized and mixed to achieve the required compositions and level of homogeneity. The homogeneity was determined using specially developed analytical methods and confirmed statistically by ANOVA. Additionally, the results of the tests show the short- and long-term stabilities of the new materials. The certified values for specific element contents were determined in interlaboratory tests. All results were assessed statistically for outliers. The results from three or more independent and different analytical methods were used for the calculations. In parallel homogeneity, the stability, and characterization standard uncertainties were calculated and used in the estimation of the final expanded uncertainties of the certified values. Finally, four new CRMs were assisted with the proper certificates according to ISO standards.

Halogenated BOIMPYs and Their Efficiency in Photodynamic Therapy

BOIMPY (bis‐ (borondifluoride)‐8‐imidazodipyrromethene) photosensitizers were developed for imaging‐guided photodynamic therapy (PDT). The introduction of heavy atoms (Br and I) to the b‐positions of BOIMPY combined with the twisted structure of the molecule was the strategy to enhance the intersystem crossing process of the BOIMPYs and reduce intermolecular π−π interactions of BOIMPY core. To clarify the electronic features of BOIMPY derivatives, their optical properties were studied using UV‐vis absorption, fluorescence spectroscopy, electrochemistry, and density functional theory (DFT) computing. The halogenated BOIMPYs exhibited a high absorption coefficient with high singlet oxygen generation ability (Φ∆ = 0.46 and 0.94 for brominated and iodinated BOIMPY, respectively). More significantly, an in vitro investigation showed that all derivatives displayed vivid fluorescence in cancer cells and that the halogenated BOIMPYs increased the effectiveness of tumor inhibition upon exposure to 660 nm red LED light radiation. The half‐maximal inhibitory concentrations for the iodinated and brominated BOIMPYs were 2.14 µM and 14.78 µM, respectively. Consequently, iodinated BOIMPY has been shown to represent a new class of photosensitizers with potential use in imaging‐guided photodynamic therapy.