ABSTRACT Rationale Migraine is a neurological disorder characterized by recurrent headache attacks. Angelicae Dahuricae Radix (ADR) and Puerariae Lobatae Radix (PLR) constitute a traditional herb pair commonly used for the treatment of migraine. However, their chemical constituents and plasma‐absorbed components have not been fully characterized. Methods Ultra‐high‐performance liquid chromatography coupled with Orbitrap tandem mass spectrometry (UPLC‐Orbitrap‐MS/MS), combined with a self‐constructed compound database and Xcalibur software, was employed to systematically characterize the chemical constituents of the ADR‐PLR herb pair and the absorbed components detected in rat plasma following intragastric administration. The MS/MS fragmentation pathways of representative compounds were also investigated. Results A total of 111 chemical constituents were characterized in the ADR‐PLR herb pair, including 31 coumarins, 61 flavonoids and their glycosides, 9 organic acids, 5 other glycosides, and 5 other compounds. A total of 21 prototype components were detected in rat plasma, of which 8 were derived from ADR and 13 from PLR. Conclusions This study systematically characterized the chemical constituents and plasma‐absorbed prototype components of the ADR‐PLR herb pair, providing a chemical basis for further investigation of its antimigraine mechanisms.
ABSTRACT Rationale Caffeinated drinks and supplements are popular products, many of which claim to use naturally derived caffeine. The availability of less expensive synthetic caffeine can motivate adulteration. Additionally, the caffeine content of these products can be inaccurately labeled, raising health concerns. As a result, effective testing methods are required to distinguish synthetic and natural caffeine and to test caffeine content in complex matrixes. In this study, a stable isotope method for natural caffeine authentication is described and applied to commercial samples. The accuracy of labeled caffeine content of products is evaluated. Methods Samples containing exclusively natural caffeine (i.e., coffee, tea, guarana, yerba mate) and synthetic caffeine were selected. Commercial products claiming to contain natural caffeine including supplements, energy drinks, and guarana products were also tested. Caffeine was extracted by incubation with a water‐ammonium hydroxide mixture and phase separation with dichloromethane. Its carbon and nitrogen stable isotope composition was determined using GC‐C‐IRMS. Caffeine content was determined by HPLC‐DAD. Results Natural and synthetic caffeine could be distinguished, with some limitations, based on carbon (δ 13 C) and nitrogen (δ 15 N) isotopes. Based on this distinction, 15 of the 75 commercial samples labeled as containing natural caffeine were adulterated. The rate of apparent adulteration was high in guarana products (~78%) and supplements (~22%). Caffeine content deviating from label claim by more than ±20% was observed in 46% of the 86 samples tested, ranging from 57% to 217% of the labeled content. Conclusions Carbon and nitrogen isotope ratio analysis by gas chromatography‐combustion‐isotope ratio mass spectrometry is an efficient method for distinguishing natural and synthetic caffeine in commercially available products. Such testing is important given the significant number of apparently mislabeled products on the USA market. The prevalence of inaccurate caffeine content labeling may raise health concerns, highlighting the need for better production quality control and increased testing.
Rationale The Ni-V-O system is of considerable importance owing to its applications in catalysis and electrochemical devices. But experimental thermodynamic data for the Ni-V-O system remain limited. The KEMS study can provide the fundamental thermodynamic data like equilibrium partial pressure of gaseous species over the condensed phase, which can be used to evaluate the thermodynamic functions for the chemical equilibria and the involved condensed phases. The thermodynamic data can be valuable for both practical applications of Ni-V-O systems and fundamental science. Method/Approach High-Temperature Knudsen Effusion Mass Spectrometry (HT-KEMS) was employed to investigate the vaporization behaviour of the Ni-V-O system. Equilibrium partial pressures of the vaporizing species were measured using electron impact ionization mass spectrometry, and the obtained data were utilized for thermodynamic evaluation of the 3V(2)O(8)(s) + NiO(s)> biphasic region in the Ni-V-O system. Results/Key Points The major vapor species detected over the sample were O-2(g), Ni(g), and VO2(g). In addition, two minor species were also detected: V(g) and NiO(g). The pressure-temperature (p-T) relations for the major species over 3V(2)O(8)(s) + NiO(s)> region were deduced in the experimental temperature range of 1476-1581 K. From the p-T and equilibrium constant-temperature (K-T) relations, based on the second and third law methods of thermodynamics, the enthalpy changes and temperature dependence of Gibbs energy of four reactions were evaluated. Subsequently, the enthalpy of formation at 298 K and Gibbs energy of formation of Ni3V2O8(s) as a function of temperature were deduced. Conclusions Thermodynamic properties of the ternary compound Ni3V2O8(s) were deduced employing HT-KEMS measurements.
Rationale Stable isotope measurements in odontocete teeth can be used to reconstruct lifetime ecology, but some pre-treatments may introduce bias. Isolating dentine collagen with HCl decalcification, removing the organic matrix or drying dentine prior to the analysis of structural carbonates can introduce unintended variability, limiting comparability among studies and populations. This study tested pre-treatment methods to quantify their effects.Methods Killer whale teeth were sectioned, annual growth layers microdrilled, and powder allocated to treatments. For collagen delta 13C and delta 15N, 75 samples were analysed via EA-IRMS as untreated bulk dentine and after 0.25 N HCl decalcification. For structural carbonate delta 13C and delta 18O, treatment with 30% H2O2 was compared with plasma-ashing and with no treatment (n = 16); and we examined the removal of residual water by comparing samples oven-dried at 80 degrees C or 100 degrees C with untreated samples (n = 10). All samples for carbonate analysis were injected with 104% orthophosphoric acid to generate CO2, which was analysed using continuous-flow IRMS.Results HCl decalcification caused mass loss (96.6% +/- 2.0%) but yielded collagen of an acceptable quality (C:N = 3.3 +/- 0.2). Compared with untreated dentine, collagen delta 13C decreased (Delta median = -0.34 parts per thousand) while delta 15N did not differ significantly. Organic-matrix removal treatments altered both isotopes: plasma-ashed samples showed large negative shifts compared with untreated samples in delta 13C (Delta median = -9.04 parts per thousand) and delta 18O (Delta mean = -13.48 parts per thousand) and reduced measurable carbon. H2O2 treatments lowered delta 13C relative to untreated samples (Delta mean = -0.93 parts per thousand) but showed no consistent delta 18O effect. Drying at 80 degrees C minimised delta 13C and delta 18O variability.Conclusions HCl decalcification is recommended before delta 13C and delta 15N collagen analysis of killer whale dentine, or a delta 13C correction factor (here -0.34 parts per thousand) should be applied. Treatments were unsuitable when undertaking structural carbonate analyses of hydroxyapatite: we suggest that untreated powder oven-dried overnight at 80 degrees C should be used, and we emphasise the importance of pre-treatment tests prior to any new study.
ABSTRACT Rationale This study evaluates the potential of Sr isotopic compositions in apatite grains from magmatic rocks as a proxy for initial 87 Sr/ 86 Sr ratios, addressing the need for alternative approaches to conventional whole‐rock analyses in isotopic studies of granitoid systems. Methods Chemical and spectrometric procedures were optimized and validated for the determination of Sr isotopic ratios in apatite by TIMS. Three representative samples from the Ribeira Orogen, Brazil, were selected, and apatite Sr isotopic compositions were compared with initial whole‐rock 87 Sr/ 86 Sr ratios calculated from U–Pb zircon crystallization ages, whole‐rock isotopic ratios, and Rb and Sr concentrations. The reliability of the analytical approach was evaluated using the EN‐1 and Durango apatite reference materials. Results Apatite grains yielded Sr concentrations ranging from 80 to 950 μg g −1 , with total Sr masses between 0.5 and 50 ng. Comparisons between apatite‐derived and whole‐rock initial 87 Sr/ 86 Sr ratios show isotopic variability below 0.05%, indicating high analytical precision. Validation results demonstrate consistent agreement between methods, with uncertainties within 0.5%. Conclusions The proposed TIMS‐based method for Sr isotope analysis in apatite grains provides a potential approach for investigating the initial Sr isotopic compositions of granitoid magmatic systems. This approach represents a cost‐effective and time‐efficient alternative to traditional whole‐rock analyses, with strong potential for large‐scale isotopic applications in orogenic terrains.
