Search Results (56)

Gallium-68 is a widely used positron-emitting radionuclide in nuclear medicine, traditionally obtained from ⁶⁸Ge/⁶⁸Ga generators. However, increasing clinical demand has driven interest in alternative production methods, such as medical cyclotrons equipped with solid targets. This study evaluates the functional equivalence of gallium-68 chloride obtained from cyclotron solid target and formulated to be equivalent to the eluate from a germanium-gallium generator, aiming to determine whether this production method can serve as a reliable alternative for PET radiopharmaceutical applications. Preparations of [⁶⁸Ga]Ga-PSMA-11 and [⁶⁸Ga]Ga-DOTATOC, labeled with cyclotron-derived gallium-68 chloride, were subjected to quality control analysis using radio thin layer chromatography and radio high performance liquid chromatography. Subsequently, biodistribution studies were performed in mouse oncological models of expression of PSMA antigen and SSTR receptor to compare uptake of preparations produced with generator and cyclotron-derived isotopes. All tested formulations met the required radiochemical purity specifications. Moreover, tumor accumulation of the radiolabeled compounds was comparable regardless of the isotope source. The results support the conclusion that gallium-68 produced via cyclotron is functionally equivalent to that obtained from a generator, demonstrating its potential for interchangeable use in clinical and research radiopharmaceutical applications. Full article

Background/Objectives. This manuscript presents an overview of advances in oncological radiotherapy as an effective treatment method for cancerous tumors, focusing on mechanisms of action within metabolite–antimetabolite systems. The urgency of this topic is underscored by the fact that cancer remains one of the leading causes of death worldwide: as of 2022, approximately 20 million new cases were diagnosed globally, accounting for about 0.25% of the total population. Given prognostic models predicting a steady increase in cancer incidence to 35 million cases by 2050, there is an urgent need for the latest developments in physics, chemistry, molecular biology, pharmacy, and strict adherence to oncological vigilance. The purpose of this work is to demonstrate the relationship between the nature and mechanisms of past diagnostic and therapeutic oncology approaches, their current improvements, and future prospects. Particular emphasis is placed on isotope technologies in the production of therapeutic nuclides, focusing on the mechanisms of formation of simple and complex theranostic compounds and their classification according to target specificity. Methods. The methodology involved searching, selecting, and analyzing information from PubMed, Scopus, and Web of Science databases, as well as from available official online sources over the past 20 years. The search was structured around the structure–mechanism–effect relationship of active pharmaceutical ingredients (APIs). The manuscript, including graphic materials, was prepared using a narrative synthesis method. Results. The results present a sequential analysis of materials related to isotope technology, particularly nucleus stability and instability. An explanation of theranostic principles enabled a detailed description of the action mechanisms of radiopharmaceuticals on various receptors within the metabolite–antimetabolite system using specific drug models. Attention is also given to radioactive nanotheranostics, exemplified by the mechanisms of action of radioactive nanoparticles such as Tc-99m, AuNPs, wwAgNPs, FeNPs, and others. Conclusions. Radiotheranostics, which combines the diagnostic properties of unstable nuclei with therapeutic effects, serves as an effective adjunctive and/or independent method for treating cancer patients. Despite the emergence of resistance to both chemotherapy and radiotherapy, existing nuclide resources provide protection against subsequent tumor metastasis. However, given the unfavorable cancer incidence prognosis over the next 25 years, the development of “preventive” drugs is recommended. Progress in this area will be facilitated by modern medical knowledge and a deeper understanding of ligand–receptor interactions to trigger apoptosis in rapidly proliferating cells. Full article

This study evaluated the authenticity of olive oil in canned tuna products from the Slovenian market using both official methods, including fatty acid (FA) profiling, determination of the equivalent carbon number difference (ΔECN42), and sterol analysis, and an advanced method: stable carbon isotope analysis (δ¹³C) of FAs obtained through compound-specific isotope analysis (CSIA). Results from both methods confirmed that all 10 samples were authentic, as per the limits set by EU Regulation 2022/2104 and supported by the scientific literature. Method performance was further evaluated by adulterating the olive oil from the canned tuna with 5–20% vegetable oil (VO) or hazelnut oil (HO). While FA analysis struggled to differentiate adulterants with similar FA profiles, CSIA of FAs significantly improved detection. However, distinguishing between VO and HO blended samples remained challenging. PLS-DA analysis further supported the potential of using δ¹³C values of FA for food authentication. Storage of adulterated samples also influenced FA composition, leading to significant changes in MUFA/PUFA ratios and δ¹³C values, which became less negative, likely due to oxidative degradation. In summary, the combination of official and advanced methods, supported by chemometric analysis, offers a robust approach to ensuring the authenticity of olive oil in canned tuna. Full article

Isotopic analyses are useful tools with a wide range of applications, including environmental studies, archaeology and biomedicine. Founded in 2019 at the University of Campania “Luigi Vanvitelli”, the iCONa laboratory specialises in stable isotope mass spectrometry, with a particular focus on cultural heritage. The laboratory performs carbon, nitrogen and oxygen isotopic analyses, including the most recent advances in compound-specific stable isotope analysis of amino acids (CSIA-AAs). In addition to these analytical services, iCONa provides chemical and physical sample preparation for a variety of sample types. This paper focuses on our applications in the field of cultural heritage, exploring how the analysis of stable isotopes performed on archaeological remains can be used to reconstruct past subsistence strategies and human behaviours. We also discuss the challenges inherent in isotopic analysis and recent methodological advances in the field. Full article

Stable isotope analysis is a powerful tool for inferring and quantifying transformation processes, but its effectiveness relies on understanding the magnitude and variability of isotopic fractionation associated with specific reactions. Potassium permanganate (KMnO₄) is widely used as an efficient oxidant for the degradation of trichloroethylene (TCE); however, the influence of environmental factors on the isotope fractionation during this process remains unclear. In this study, compound-specific isotope analysis (CSIA) was conducted to investigate the variability in carbon isotope effects during the KMnO₄-mediated degradation of TCE under varying conditions, including initial concentrations of KMnO₄ and TCE, the presence of humic acid (HA), pH levels, and inorganic ions. The results showed that the overall carbon isotope enrichment factors (ε) of TCE ranged from −26.5 ± 0.5‰ to −22.8 ± 0.9‰, indicating relatively small variations across conditions. At low KMnO₄/TCE molar ratio (n(KMnO₄)/n(TCE)), incomplete oxidation and/or MnO₂-mediated oxidation of TCE likely resulted in smaller ε. For dense, non-aqueous phase liquid (DNAPL) TCE, which represents extremely high concentrations, the ε value was −13.0 ± 1.7‰ during KMnO₄ oxidation. This may be attributed to the slow dissolution of isotopically light TCE from the DNAPL phase, altering the δ¹³C signature of the reacted TCE and resulting in a significantly larger ε value than observed for dissolved-phase TCE oxidation. The ε values increased with rising pH, probably due to the decrease in oxidation potential (E₀) of KMnO₄ from pH ~2 to ~12, as well as the emergence of different degradation pathways and intermediates under varying pH conditions. Both SO₄²⁻ and NO₃⁻ slightly influenced the ε values, potentially due to the formation of H₂SO₄ and HNO₃ at lower pH, which may act as auxiliary oxidants and contribute to TCE degradation. A high concentration (50 mM) of HA led to a decrease in ε values, likely due to competitive interactions between HA and TCE for KMnO₄, which reduced the effective oxidation of TCE. Overall, the carbon isotope enrichment factors for KMnO₄-mediated TCE degradation are relatively stable, although certain environmental conditions can exert minor influences. These findings highlight the need for caution when applying quantitative assessment based on CSIA for KMnO₄ oxidation of TCE. Full article

Nitrogen deposition is a critical driver of plant-soil interactions in forest ecosystems. However, the species-specific coordination of nitrogen uptake and carbon assimilation—traced using ¹⁵N- and ¹³C-labeled compounds—under varying nitrogen forms, depths, and time points remains poorly understood. We conducted a dual-isotope (¹⁵NH₄Cl, K¹⁵NO₃, and Na₂¹³CO₃) labeling experiment in a temperate secondary forest to investigate nutrient uptake and carbon assimilation in three understory species—Carex siderosticta, Maianthemum bifolium, and Oxalis acetosella—across three nitrogen treatments (control, low N, and high N), two soil depths (0–5 cm and 5–15 cm), and two post-labeling time points (24 h and 72 h). We quantified ¹⁵N uptake and ¹³C assimilation in above- and belowground plant tissues, as well as ¹⁵N and ¹³C retention in soils. C. siderosticta exhibited the highest total ¹⁵N uptake (2.2–6.9 μg N m⁻² aboveground; 1.4–4.1 μg N m⁻² belowground) and ¹³C assimilation (58.4–111.2 mg C m⁻² aboveground; 17.6–39.2 mg C m⁻² belowground) under high ammonium at 72 h. High nitrogen input significantly enhanced the coupling between plant biomass and nutrient assimilation (R² > 0.9), and increased ¹⁵N-TN and ¹³C-SOC retention in the surface soil layer (13,200–17,400 μg N kg⁻¹; 30,000–44,000 μg C kg⁻¹). Multifactorial analysis revealed significant interactions among nitrogen treatment, form, depth, and time. These findings demonstrate that ammonium-based enrichment promotes nutrient acquisition and carbon assimilation in responsive species and enhances surface soil C—N retention, highlighting the integrative effects of nitrogen form, species traits, and spatial–temporal dynamics on forest biogeochemistry. Full article

Stable isotope ratio analysis of carbon (δ¹³C) and hydrogen (δ²H) in vanillin has become a valuable tool for differentiating natural vanilla from synthetic or biosynthetic alternatives and for tracing its geographical origins. However, increasingly sophisticated fraud techniques necessitate ongoing refinement of analytical methods to ensure accurate detection. This study advanced the field by investigating minor volatile organic compounds as potential biomarkers for identifying botanical and geographical origins of vanilla products. Vanilla pods from the two main vanilla species, V. planifolia and V. tahitensis, were investigated using GC-MS/MS to analyze their aromatic profile and GC-C/Py-IRMS to determine compound-specific isotope ratios, providing, for the first time, detailed and authentic isotopic and aromatic profiles. Additionally, the potential natural presence of ethyl vanillin and its corresponding glucoside precursors—molecules commonly used as synthetic vanilla-scented fragrance agents in various foods and industrial products—was explored using UHPLC-HRMS. These findings contribute to robust methods for verifying vanilla authenticity, addressing flavor complexity and isotopic composition, and enhancing the detection of adulteration in vanilla-flavored products. Full article

The aim of this study was to test the hypothesis that both the winter triticale genotype and salinity treatment influence the photosynthesis efficiency and content of metabolites and proteins, including antioxidant enzymes, under field conditions, as well as that these parameters are correlated with yielding capacity. The research material involved four genotypes differing in their tolerance to stress in previous tests. Chlorophyll a fluorescence parameters and antioxidant activity were assessed in the seedlings. Specific antibodies were then used to verify the involvement of selected proteins. Simultaneously, Raman spectroscopy was employed to detect chlorophyll, carotenoids, phenolic compounds, and protein levels. The findings suggest that improved PSII performance, reduced catalase activity, increased pigment levels, and higher thioredoxin reductase abundance in the seedlings were associated with better yield potential in triticale genotypes grown under salt stress conditions. The Raman analysis revealed that salinity caused changes in the photosynthetic pigments, particularly carotenoids. The carbon isotope ratios indicate that the salinization generated different physiological stresses in the availability of water. Full article

Background: Honey is one of the most adulterated foods worldwide, and several analytical methods have been developed over the last decade to detect syrup additions to honey. These include approaches based on stable isotopes and the specific detection of individual marker compounds or foreign enzymes. Proton nuclear magnetic resonance (¹H-NMR) spectroscopy is applied as a rapid and comprehensive screening method, which also enables the detection of quality parameters and the analysis of the geographical and botanical origin. However, especially for the detection of foreign sugars, ¹H-NMR has insufficient sensitivity. Methods: Since untargeted liquid chromatography–mass spectrometry (LC-MS) is more sensitive, we used this approach for the detection of positive and negative ions in combination with a recently developed data processing workflow for routine laboratories based on bucketing and random forest for the detection of rice, beet and high-fructose corn syrup in honey. Results: We show that the distinction between pure and adulterated honey is possible for all three syrups, with classification accuracies ranging from 98 to 100%, while the accuracy of the syrup content estimation depends on the respective syrup. For rice and beet syrup, the deviations from the true proportion were in the single-digit percentage range, while for high-fructose corn syrup they were much higher, in some cases exceeding 20%. Conclusions: The approach presented here is very promising for the robust and sensitive detection of syrup in honey applied in routine laboratories. Full article

Among the Moscato grapes, Moscato Giallo is a winegrape variety characterised by a high content of free and glycosylated monoterpenoids, which gives wines very intense notes of ripe fruit and flowers. The aromatic bouquet of Moscato Giallo is strongly influenced by the high concentration of linalool, geraniol, linalool oxides, limonene, α-terpineol, citronellol, hotrienol, diendiols, trans/cis-8-hydroxy linalool, geranic acid and myrcene, that give citrus, rose, and peach notes. Except for quali-quantitative analysis, no investigations regarding the isotopic values of the target volatile compounds in grapes and wines are documented in the literature. Nevertheless, the analysis of the stable isotope ratio represents a modern and powerful tool used by the laboratories responsible for official consumer protection, for food quality and genuineness assessment. To this aim, the aromatic compounds extracted from grapes and wine were analysed both by GC-MS/MS, to define the aroma profiles, and by GC-C/Py-IRMS, for a preliminary isotope compound-specific investigation. Seventeen samples of Moscato Giallo grapes were collected during the harvest season in 2021 from two Italian regions renowned for the cultivation of this aromatic variety, Trentino Alto Adige and Veneto, and the corresponding wines were produced at micro-winery scale. The GC-MS/MS analysis confirmed the presence of the typical terpenoids both in glycosylated and free forms, responsible for the characteristic aroma of the Moscato Giallo variety, while the compound-specific isotope ratio analysis allowed us to determine the carbon (δ¹³C) and hydrogen (δ²H) isotopic signatures of the major volatile compounds for the first time. Full article

Accurate measurement of steroid hormones is crucial to elucidate new mechanisms of action and diagnose steroid metabolism-related diseases. This study presents a simple, sensitive, and automated analytical method for nine representative steroid hormones. The method involves on-line coupling of in-tube solid-phase microextraction (IT-SPME) with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The steroid hormones were extracted and enriched on a Supel-Q PLOT capillary column using IT-SPME. Subsequently, they were separated and detected within 6 min using a Discovery HS F5-3 column and positive ion mode multiple reaction monitoring system via LC–MS/MS. Calibration curves of these compounds using each stable isotope-labeled internal standard (IS) showed linearity with correlation coefficients greater than 0.9990 in the range of 0.01–40 ng/mL, with limits of detection (S/N = 3) of 0.7–21 pg/mL. Moreover, intra- and inter-day variations were lower than 8.1 and 15% (n = 6), respectively. The recoveries of these compounds from saliva samples were in the range of 82–114%. The developed IT-SPME/LC–MS/MS method of steroid hormones is a highly sensitive, specific, and non-invasive analytical method that allows extraction and enrichment with no organic solvents, and enables direct automated online analysis by simply ultrafiltrating a small sample of saliva. Full article

The exceptionally low geothermal gradient (~2 °C/100 m) in the Tarim Basin, notably in the Shuntuoguole (STGL) area with depths exceeding 7000 m, has catalyzed the discovery of ultra-deep liquid hydrocarbons. Yet, the genesis of these hydrocarbons remains elusive, presenting significant challenges to further exploration and development endeavors. To address this quandary, an extensive analysis involving biomarker assessments and compound-specific δ²H and δ¹³C isotopic evaluations of n-alkanes was conducted, unveiling the secondary alterations and origins of these crude oils. For the first time, an approximately horizontal distribution of compound-specific δ²H and δ¹³C in n-alkanes was observed. Through the integration of diagnostic biomarker compounds, it was elucidated that the STGL crude oils did not undergo significant biodegradation, thermal alteration, or thermal sulfate reduction. Biomarker- and compound-specific C/H isotopic correlations suggest that the STGL crude oil predominantly originates from the Lower Cambrian calcareous shale, positing it as a potential end-member oil for this lithofacial source rock. Furthermore, the STGL crude oil exhibits similar biomarker configurations (notably abundant C₂₈ triaromatic sterones, C₂₃ tricyclic terpenoids, and aryl isoprenoids, with minimal 4-methylstane and gammacerane presence) to those oils previously considered as mixed from the Tazhong and Tabei Uplifts within the Tarim Basin. This similarity suggests that these previously deemed mixed oils may also derive from the Lower Cambrian calcareous shale. Consequently, more focused investigations into the Lower Cambrian calcareous shale are imperative to bolster refined deep and ultra-deep petroleum exploration efforts within the Tarim Basin in forthcoming studies. Full article

Compound-specific isotope analysis (CSIA) can provide unique insights into the cycling of elements including carbon and nitrogen. One approach for CSIA is the use of high-performance liquid chromatography (HPLC) to separate compounds of interest, followed by analysis of these compounds using an elemental analyser coupled to an isotope ratio mass spectrometer. A key component of this technique is the fraction collector, which automatically collects compounds as they are separated by HPLC. Here, we present a fraction collector that is a simple adaptation of a 3D printer, and, thus, can be easily adopted by any laboratory already equipped for HPLC. In addition to the much lower cost compared to commercial alternatives, this adaptation has the advantage for CSIA that the 3D printer is able to heat the collected fractions, which is not true for many commercial fraction collectors. Heating allows faster evaporation of the solvent, so that the dried compounds can be measured by EA–IRMS immediately. The procedure can be repeated consecutively so that diluted solutions can have the compounds concentrated for analysis. Any computer-controlled HPLC can be integrated to the fraction collector used here by means of AutoIt. Full article

To bridge the gap between lab-scale microcosm research and field application in the compound-specific stable isotope analysis (CSIA) of atrazine, we studied the characteristics of carbon and nitrogen isotope fractionation in the atrazine degradation processes within a constructed wetland. In the wetland, we observed multiple element (C, N) isotope fractionation parameters, such as kinetic isotope effects and dual isotope slopes. These parameters are very consistent with those observed in the cultivation of AtzA- or TrzN-harboring strains, suggesting a similarity in the pathway and reaction mechanism of atrazine biodegradation between the two settings. However, we recorded variable carbon (${\epsilon }_C:$−3.2 ± 0.6‰ to −4.3 ± 0.6‰) and nitrogen isotope fractionation (${\epsilon }_N:$1.0 ± 0.3‰ to 2.2 ± 0.3‰) across different phases. This variance could lead to an over- or underestimation of the biodegradation extent of atrazine when employing the large or small enrichment factor of the carbon isotope. Intriguingly, the estimation accuracy improved considerably when using the enrichment factor (−4.6‰) derived from the batch cultivation of the pore water. This study advances the application of CSIA in tracking atrazine biodegradation processes in ecosystems, and it also underlines the importance of the careful selection and application of the enrichment factor in quantifying the intrinsic biodegradation of atrazine in ecosystems. Full article

Carbonate rocks exhibit significant heterogeneity as both a source rock and reservoir. Stylolite formation plays a crucial role in the enrichment of organic matter and the migration of geofluids within carbonate rocks. In order to study the enrichment mechanism of organic matter and the geofluid migration mode in the stylolites developed in carbonate rocks, stylolite-bearing core samples from the Dachigan structural belt in the eastern Sichuan Basin were collected. The stylolites and matrix were subjected to the total organic carbon (TOC) test and Rock-Eval pyrolysis, thin-section observation under fluorescent light, whole-rock X-ray diffraction, carbon and oxygen isotope analysis, and scanning electron microscopy. The organic matter occurring in the stylolites is mainly in the form of three types: soluble organic matter, pyrobitumen, and bitumen. This suggests that the organic matter within the stylolites mainly consists of secondary migrated organic matter. The stylolites also exhibit well-developed secondary dolomite and pyrite resulting from late-diagenetic recrystallization. These minerals contribute to the preservation of intercrystalline pore spaces and fractures, providing favorable conditions for oil and gas accumulation and migration. The strong cementation observed at the contact between the stylolites and matrix, along with the presence of secondary minerals nearby, may be attributed to the fractionation of light and heavy oil components during the migration of hydrocarbon fluids from the matrix to the stylolites. The thicknesses of the stylolites vary within the bulk, indicating severe diagenesis in thinner areas. Consequently, this leads to significant fractionation effects. The fractionation of crude oil components by stylolites poses challenges for the study of definitive oil–source correlations. To overcome these challenges, future research could investigate biomarker compounds to attempt oil–source correlations. Additionally, future efforts should take into consideration the spatial variation in the crude oil properties. Understanding the role of stylolites in organic matter enrichment and geofluid migration is crucial for optimizing exploration strategies in the Sichuan Basin, a region of growing importance in the energy industry. Moreover, our findings shed light on the complex interactions within stylolite-bearing rocks, which are not limited to this specific basin. These insights offer valuable contributions to the broader field of geology and reservoir characterization, enhancing our ability to predict and interpret similar geological formations globally. Full article