Spectroscopic Analysis Methods Research Articles

Pesticides in surface water of the Ondas river watershed, western Bahia, Brazil: Spatial-seasonal distribution and risk assessment

This study investigated the occurrence and seasonal distribution of different classes of pesticides in surface waters of the Ondas River Watershed, as well as potential risks to the aquatic health and human water consumption in the western region of Bahia state, Brazil. Two gas chromatography-mass spectrometry analytical methods were applied to monitor 34 pesticides in water samples collected during both the dry and rainy seasons at 17 sites. Upon individual analysis, only γ-HCH, methoxychlor, demeton-S, methyl parathion, fenitrothion, chlorpyrifos, and azoxystrobin exhibited statistically significant differences between seasons. During rainy season, concentration medians of residues were higher for γ-HCH (74.7 ng L−1), methoxychlor (25.1 ng L−1), and azoxystrobin (47.2 ng L−1), potentially linked to historical contamination or illegal use. Conversely, pesticides like methyl parathion, fenitrothion, and chlorpyrifos, belonging to the organophosphate class, showed higher concentration medians in the dry period, measuring 75.1, 5.50, and 10.8 ng L−1, respectively, probably due to region crop activities. The risk quotient (RQ) assessment for aquatic life indicated that 59.0% of the samples in the dry season and 76.0% in the rainy season had RQ values greater than one, signifying a critical scenario for species conservation. Regarding human consumption, elevated risks were observed for heptachlor in both sampling periods and for azoxystrobin during the rainy season, surpassing RQ levels above 1, indicating danger in untreated water ingestion. Additionally, 24.0% and 53.0% of the samples in the dry and rainy seasons, respectively, contained at least one pesticide exceeding the EU resolution limit (100 ng L−1). Therefore, considering this information, implementing mitigation measures to avoid the river's contamination becomes imperative.

Neural Network Model for Surface Raman Spectroscopy and Pesticide Concentration of Spinach

At present, there are over 1000 chemical pesticides. The widespread use of these pesticides not only causes serious environmental pollution, but also poses a threat to human health. Currently, there are over 1000 types of chemical pesticides. The widespread use of these pesticides has caused serious environmental pollution. Meanwhile, due to some workers not effectively removing pesticides from food during the picking and processing stages of the farm plants, so the long-term consumption of such food will also pose a threat to human health. An analytical technique called Raman spectroscopy is based on the Raman scattering effect, which was discovered by Indian scientist C.V. Raman. It is used in molecular structure research to get data on molecule vibration and rotation by analyzing scattering spectra at various frequencies from incident light. As a newborn way, the Raman spectroscopy analysis method has higher sensitivity. In this thesis, I put it and the BP neural network together and set up the model, to predict pesticide residues in spinach.

New Strategy for the Synthesis of Some Valuable Chiral 1,3-Diols with High Enantiomeric Purity: New Organocatalyst, Asymmetric Aldol Reaction, and Reduction.

Chiral 1,3-diols are highly valuable molecules used in industries such as pharmaceuticals, cosmetics, and agriculture. Therefore, in this study, a new strategy was developed to synthesize enantiomerically pure (>99% ee) 1,3-diols. New chiral 1,3-diols (5a-5q) with high enantiomeric purity were synthesized from aldol products chiral 1,3-keto alcohols (4a-4q), which are aldol products with different structures. Chiral 1,3-keto alcohols (4a-4q) were synthesized by a new asymmetric aldol method in the first step. This method was developed using a new proline-derived organocatalyst (3g) and Cu(OTf)2 as an additive in DMSO-H2O for the first time. Almost >99% ee was obtained using our developed aldol procedure. In the second step, original chiral diols (5a-5q) of high enantiomeric purity were obtained by asymmetric reduction of chiral keto alcohols with chiral oxazaborolidine reagents. In this way, a two-step asymmetric reaction was developed for chiral 1,3-diol enantiomers with high enantiomeric purity. The structures of all the original chiral compounds obtained were elucidated by infrared and nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis methods. Their enantiomeric excesses were determined by the chiral high-performance liquid chromatography method. Both keto alcohols and their corresponding chiral diols synthesized can be used as chiral starting materials and chiral source materials or intermediates in the synthesis of many biologically active molecules, or they can be used as chiral ligands in asymmetric synthesis, serving as organocatalysts.

Two previously undescribed cholestanol saponins from the rhizomes of Paris fargesii var. petiolata

Two previously undescribed cholestanol saponins, parpetiosides F − G (1–2), and six known analogs (3–8) were isolated from the rhizomes of Paris fargesii var. petiolata. Their structures were elucidated by extensive spectroscopic data analysis and chemical methods. Compound 1 was a rare 6/6/6/5/5 fused-rings cholestanol saponin with disaccharide moiety linked at C-26 of aglycone which was hardly seen in genus Paris. All of these compounds were discovered in this plant for the first time. In addition, the cytotoxicities of saponins (1–8) against three human cancer cell lines (U87, HepG2 and SGC-7901) were evaluated by CCK-8 method, and saponins 5–8 displayed certain cytotoxicities. The strong interactions between saponins 5–8 and SCUBE3, an oncogene for glioma cells, were displayed by molecular docking.

A novel method for the remediation of o‐ and p‐aminophenol from industrial wastewater by hexacyanoferrate (III) ions using Ir‐complex catalyst

AbstractIn this manuscript o‐ and p‐aminophenols model environmental pollutants are being remedied by catalytic oxidation process. A kinetic‐spectrophotometric technique was used to study the remediation of o‐ and p‐aminophenol by hexacyanoferrate (III) ions as an oxidant and synthesized Ir‐DTPy complex as a catalyst in aqueous alkaline medium. The optimum pH for these experiments was 9.0 and 11.0 for o‐ and p‐aminophenol respectively at the constant temperature 25°C. It has been studied how variations in the concentration of the catalyst (Ir‐DTPy), the hexacyanoferrate (III) ions, and substrate affect the rate of the reaction. At four different temperatures, ranging from 25 to 40°C, the change in reaction rate has been analyzed with thermodynamic variables like free energy of activation, enthalpy, frequency factor, and activation energy. FTIR, UV‐Vis, and ESI‐MS spectroscopic analytical methods have been used to identify the oxidized products. 2‐aminophenoxazin‐3‐one and NN'‐bis‐(p‐hydroxyphenyl)‐2‐hydroxy‐5‐amino‐1, 4‐benzoquinone di‐imine are the main products of oxidation of o‐and p‐aminophenol, respectively. Therefore, this technique for removing o‐ and p‐aminophenol from contaminated water resources is very effective and environmentally safe.

Screening and evaluation of quality markers of Radix Cudramiae for liver disease based on an integrated strategy of in vivo pharmacokinetics and in vitro HPLC fingerprint

Radix Cudramiae, the dried root of Cudrania cochinchinensis (Lour.) Kudo et Masam., is a valuable ethnomedicine with outstanding antihepatitis activity. However, the lack of reports on quality markers (Q-markers) hindered its quality evaluation and standardization, as a result restricted its clinical application. This paper aimed to discover the Q-markers of Radix Cudramiae with a comprehensive strategy based on in vivo pharmacokinetics and in vitro HPLC fingerprint. A rapid and sensitive ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) analytical method was firstly developed and validated for simultaneous determination of six potential active ingredients (eriodictyol, dihydrokaempferol, dihydromorin, kaempferol, naringenin and morin) of Radix Cudramiae in rat plasma and tissues, which was successfully applied to the holistic comparison of pharmacokinetics and tissue distribution between normal and acute liver injury rats. On the other hand, a representative HPLC fingerprint of Radix Cudramiae was also established to elucidate the chemical profile for overall quality evaluation. Dihydrokaempferol-7-O-β-D-glucoside (the naturally existed chemical formation of dihydrokaempferol) and kaempferol screened out with high exposure levels in vivo and high resolution in HPLC fingerprint were finally selected as Q-markers of Radix Cudramiae. To the best of our knowledge, it was the first time for people to discover in vivo properties and pharmacokinetic parameters of components in Radix Cudramiae, as well as the first report on its representative HPLC fingerprint. Also, the integrated strategy could offer an effective way for TCMs Q-markers screening.

Synthesis, characterization, in silico and in vitro studies of novel glycoconjugates as potential antibacterial, antifungal, and antileishmanial agents

Abstract In the present work, several new glycoconjugates (8a–e) were generated from glycopyranosyl-α-trichloroacetimidates (sugar-OTCA) as glycosyl donors and dimethyl-l-tartrate as an aglycone acceptor in good to excellent yields. In the synthetic protocol, various monosaccharides were transformed into pentaacetylated derivatives and then into glycopyranosyl-α-trichloroacetimidates. Afterward, the sugar-OTCA was reacted with dimethyl-l-tartrate using Schmidt’s trichloroacetimidate protocol to give the desired products. The newly synthesized glycoconjugates were characterized by FT-IR, 1H, and 13C-NMR spectroscopic analytical methods. All the target compounds (8a–e) were tested in vitro against various strains of bacteria and fungi at different concentrations. The results revealed that the target compounds had encouraging antibacterial and antifungal potential. The antileishmanial activity of the target compounds against Leishmania tropica promastigotes was also investigated. The in vitro results were further supported by the in silico docking study that indicated minimum values of the docking scores and binding energies for the resulting complexes obtained by the favorable interactions between the target compounds (8a–e) and the selected strains of bacteria and fungi. The docking results proposed promising antibacterial and antifungal activities of the target compounds (8a–e) against the selected bacterial and fungal species.

Preparation and identification of galacto-mannooligosaccharides generated from guar gum by a recombinant β-mannanase from Bacteroides fragilis (BF0736)

Guar gum (GG) containing mainly galactomannan (GM) is one of the most used hydrocolloids in food industry. β-Mannooligosaccharides (β-MOS) as building blocks generated from GG are potential prebiotics, yet their structures are still unclear. Preparation of GG-derived β-MOS and decoding the galactose substitution information of β-MOS are an ongoing challenge. Here, a novel β-mannanase BF0736 that belongs to the glycoside hydrolase family 26 from Bacteroides fragilis NCTC 9343 strain was cloned and applied to degrade GG for preparation of β-MOS mixture with a yield of 81.3 ± 2.2% (w/w; relative to GG). Eleven major galacto-mannooligosaccharides (G-MOS) with degree of polymerization (DP) 2–11 were purified from the mixture by SEC and HPAEC techniques. A new strategy for decoding the galactose substitution information of G-MOS was developed by using two-step labeling (derivatizations of anomeric site in mannose and primary hydroxyl group site in galactose) combined with tandem mass spectrometry analysis methods. Precise structures of these G-MOS were characterized, and eight oligosaccharides including 63-α-d-galactosyl-β-d-mannotriose, 61,63-di-α-d-galactosyl-β-d-mannotriose, 63,64-di-α-d-galactosyl-β-d-mannotetraose, 61,63,64-tri-α-d-galactosyl-β-d-mannotetraose, 63,64,65-tri-α-d-galactosyl-β-d-mannopentaose, 61,63,64,65-tetra-α-d-galactosyl-β-d-mannopentaose, 63,64,65,66-tetra-α-d-galactosyl-β-d-mannohexaose and 61,63,64,65,66-penta-α-d-galactosyl-β-d-mannohexaose were prepared and identified from GG for the first time, which provided critical insights into the distribution pattern of galactose in GG. Our results contribute to the utilization of GG and its derived β-MOS in functional foods.

Novel quinazolines bearing 1,3,4-thiadiazole-aryl urea derivative as anticancer agents: design, synthesis, molecular docking, DFT and bioactivity evaluations

A novel series of 1-(5-((6-nitroquinazoline-4-yl)thio)-1,3,4-thiadiazol-2-yl)-3-phenylurea derivatives 8 were designed and synthesized to evaluate their cytotoxic potencies. The structures of these obtained compounds were thoroughly characterized by IR, 1H, and 13C NMR, MASS spectroscopy and elemental analysis methods. Additionally, their in vitro anticancer activities were investigated using the MTT assay against A549 (human lung cancer), MDA-MB231 (human triple-negative breast cancer), and MCF7 (human hormone-dependent breast cancer). Etoposide was used as a reference marketed drug for comparison. Among the compounds tested, compounds 8b and 8c demonstrated acceptable antiproliferative activity, particularly against MCF7 cells. Considering the potential VEGFR-2 inhibitor potency of these compounds, a molecular docking study was performed for the most potent compound, 8c, to determine its probable interactions. Furthermore, computational investigations, including molecular dynamics, frontier molecular orbital analysis, Fukui reactivity descriptor, electrostatic potential surface, and in silico ADME evaluation for all compounds were performed to illustrate the structure–activity relationship (SAR).

Ultra‐high‐performance liquid chromatography‐tandem mass spectrometry analytical method for the determination of nitrosamine drug substance‐related impurity in sitagliptin base and salts

AbstractA reversed‐phase ultra‐high‐performance liquid chromatography‐tandem mass spectrometry method is presented for the quantification of the mutagenic impurity 7‐nitroso‐3‐(trifluoromethyl)‐5,6,7,8‐tetrahydro‐[1,2,4]triazolo[4,3‐a]pyrazine found in three sitagliptin drug substances (sitagliptin base [SG], sitagliptin hydrochloride monohydrate [SG HCl{H}] salt, and sitagliptin phosphate monohydrate [SG P{H}] salt). A simple and highly sensitive method was developed for SG, SG HCl(H) salt, and SG P(H) salt. Sample preparation was adapted to each product considering solubility, sensitivity, and accuracy issues. Chromatographic separation was achieved using an Acquity HSS T3 column (3.0 × 100 mm, 1.8 μm) and a mobile phase consisting of formic acid 0.1% in water combined with methanol. Detection and quantification of the impurity were carried out using triple quadrupole mass spectrometry detection with electrospray ionization in the multiple reaction monitoring mode. The limit of detection and limit of quantification was found to be 0.1–0.3 and 10 ppb, respectively. The accuracy and precision of the method were satisfactorily determined with recovery values between 74.1% and 119.4%. Linearity is demonstrated in the range of 10 and 2000 ppb with regression coefficients (R) within the range of 0.9918–0.9972. The method is currently used for the analysis of the mutagenic impurity in the three‐drug substances in the Moehs Group.

2-Deoxyglucose and hydroxychloroquine HPLC-MS-MS analytical methods and pharmacokinetic interactions after oralco-administration in male rats.

Our previous work has shown a synergistic tumoricidal efficacy of combining the hexokinase (HK) inhibitor 2-deoxyglucose (2-DG) and the autophagy inhibitor chloroquine (CQ) through intraperitoneal injections on HK2-addicted prostate cancers in animal models. The pharmacokinetic (PK) behaviors of these oral drugs after simultaneous oral administration have not been reported. We developed high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) analytical methods for 2-DG and the clinically favored drug hydroxychloroquine (HCQ) for sera samples. Using a jugular vein-cannulated male rat model with serial blood collection before and after a single gavage dose of each drug alone or in combination, we examined their PK metrics for drug-drug interactions. The data demonstrated a rapid and complete separation of 2-DG from common monosaccharides by HPLC-MS-MS multi-reaction monitoring. Application of the HPLC-MS-MS 2-DG and HCQ methods to sera samples of nine rats showed a peak time (Tmax ) for 2-DG of 0.5 h after 2-DG alone or with HCQ and identical post-peak half-life of approximately 1 h. With a seemingly bi-modal time course for HCQ, the Tmax for HCQ alone (1.2 h) was faster than that for the combination (2 h; p = .017). After combination dosing, the peak concentration (Cmax ) and area under the curve (AUC0-4h ) of 2-DG were decreased by 53.8% (p = .0004) and 53.7% (p = .0001), whereas AUC0-8h for HCQ was decreased by 30.8% (p = .0279) from the respective single dosing. Without changing the mean residence time (MRT0-∞ ) of each drug, the combination affected the apparent volume of distribution (Vd ) and clearance (CL) of 2-DG, and CL for HCQ without affecting its Vd . We observed significant negative PK interactions, probably at the intestinal absorption level, between 2-DG and HCQ taken simultaneously by mouth. Future optimization efforts are warranted for their combination regimen for clinical translation.

Research on detection of potato varieties based on spectral imaging analytical algorithm

Potatoes are popular among consumers due to their high yield and delicious taste. However, due to the numerous varieties of potatoes, different varieties are suitable for different processing methods. Therefore, it is necessary to distinguish varieties after harvest to meet the needs of processing enterprises and consumers. In this study, a new visible-near-infrared spectroscopic analysis method was proposed, which can achieve detection of five potato varieties. The method measures the transmission and reflection spectra of potatoes using a spectral acquisition system, encodes one-dimensional spectra into two-dimensional images using Gramian Angular Summation Field (GASF), Gramian Angular Difference Field (GADF), Markov Transition Field (MTF) and Recurrence Plot (RP), and improves the coordinated attention mechanism module and embeds the improved module into the ConvNeXt V2 model to build the ConvNeXt V2-CAP model for potato variety classification. The results show that compared with directly using one-dimensional classification models, image encoding of spectral data for classification greatly improves the accuracy. Among them, the best accuracy of 99.54% is achieved by using GADF image encoding of transmission spectra combined with the ConvNeXt V2-CAP model for classification, which is 16.28% higher than the highest accuracy of the one-dimensional classification model. The CAP attention mechanism module improves the performance of the model, especially when the dataset is small. When the training set is reduced to 150 images, the accuracy of the model is improved by 2.33% compared to the original model. Therefore, it is feasible to classify potato varieties using visible-near infrared spectroscopy and image encoding technology.

Screening and Evaluation of Children's Sensitively Toxic Chemicals in New Mosquito Repellent Products Based on a Nationwide Investigation.

New mosquito repellent products (NMRPs) are emerging popular repellents among children. There are increasing reports on children's sensitization reactions caused by NMRPs, while regulations on their productions, sales, or usage are still lacking. One of the reasons could be the missing comprehensive risk assessment. We first conducted a nationwide investigation on children's NMRP usage preferences. Then, we high-throughput screened volatile or semivolatile organic chemicals (VOCs/SVOCs) in five representative NMRPs by the headspace gas chromatography-orbitrap high-resolution mass spectrometry analytical method. After that, toxic compounds were recognized based on the toxicity forecaster (ToxCast) database. A total of 277 VOCs/SVOCs were recognized, and 70 of them were identified as toxic compounds. In a combination of concentrations, toxicities, absorption, distribution, metabolism, and excretion characteristics in the body, 28 chemicals were finally proposed as priority-controlled compounds in NMRPs. Exposure risks of recognized toxic chemicals through NMRPs by inhalation and dermal intake for children across the country were also assessed. Average daily intakes were in the range of 0.20-7.31 mg/kg/day for children in different provinces, and the children in southeastern coastal provinces were found to face higher exposure risks. By controlling the high-priority chemicals, the risks were expected to be reduced by about 46.8% on average. Results of this study are therefore believed to evaluate exposure risks, encourage safe production, and promote reasonable management of NMRPs.

Expert System for Fourier Transform Infrared Spectra Recognition Based on a Convolutional Neural Network With Multiclass Classification.

Fourier transform infrared spectroscopy (FT-IR) is a widely used spectroscopic method for routine analysis of substances and compounds. Spectral interpretation of spectra is a labor-intensive process that provides important information about functional groups or bonds present in compounds and complex substances. In this paper, based on deep learning methods of convolutional neural networks, models were developed to determine the presence of 17 classes of functional groups or 72 classes of coupling oscillations in the FT-IR spectra. Using web scanning, the spectra of 14 361 FT-IR spectra of organic molecules were obtained. Several different variants of model architectures with different sizes of feature maps have been tested. Based on the Shapley additive explanations (SHAP) and gradient-weighted class activation mapping (GradCAM) methods, visualization tools have been developed for visualizing and highlighting the areas of absorption bands manifestation for corresponding functional groups or bonds in the spectrum. To determine 17 and 72 classes, the F1-weighted metric, which is the harmonic mean of the class' precision and class' recall weighted by class' fraction, reached 93 and 88%, respectively, when using data on the position of absorption maxima in the spectrum as an additional source layer. The resulting model can be used to facilitate the routine analysis of spectra for all areas such as organic chemistry, materials science, and biology, as well as to facilitate the preparation of the obtained experimental data for publication.

Principles, developments, and applications of spatially resolved spectroscopy in agriculture: a review.

Agriculture is the primary source of human survival, which provides the most basic living and survival conditions for human beings. As living standards continue to improve, people are also paying more attention to the quality and safety of agricultural products. Therefore, the detection of agricultural product quality is very necessary. In the past decades, the spectroscopy technique has been widely used because of its excellent results in agricultural quality detection. However, traditional spectral inspection methods cannot accurately describe the internal information of agricultural products. With the continuous research and development of optical properties, it has been found that the internal quality of an object can be better reflected by separating the properties of light, such as its absorption and scattering properties. In recent years, spatially resolved spectroscopy has been increasingly used in the field of agricultural product inspection due to its simple compositional structure, low-value cost, ease of operation, efficient detection speed, and outstanding ability to obtain information about agricultural products at different depths. It can also separate optical properties based on the transmission equation of optics, which allows for more accurate detection of the internal quality of agricultural products. This review focuses on the principles of spatially resolved spectroscopy, detection equipment, analytical methods, and specific applications in agricultural quality detection. Additionally, the optical properties methods and direct analysis methods of spatially resolved spectroscopy analysis methods are also reported in this paper.

Volatile-compound fingerprinting and discrimination of positional isomers in stamp-pad ink tracing using HS-GC-IMS combined with multivariate statistical analysis.

The rising crime rate associated with document forgery has a significant impact on public safety and social stability. In document fraud cases, determining the origin of a particular stamp-pad ink is the most important objective. In this study, a comprehensive analysis of the volatile compounds in quick-drying stamp-pad inks from six commonly used brands were performed for the first time, utilizing a combination of headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and multivariate statistical analysis methods. Visual and comparative analysis of the differential volatile components among different stamp-pad ink samples was conducted using fingerprints and volcano plots. A total of 127 volatile compounds were accurately identified, with ketones, esters, alcohols, and aldehydes being the most abundant compounds in the stamp-pad inks. Hierarchical clustering analysis (HCA), including dendrograms and clustering heatmaps, was utilized to explore the correlations between these compounds and the samples. Additionally, the precise identification of positional isomers and functional group isomers of aliphatic compounds was achieved. To achieve accurate discrimination of various stamp-pad ink samples, a multivariate statistical analysis method was utilized to establish a classification model for them. Based on the results obtained from HS-GC-IMS, effective discrimination among different brands of stamp-pad ink samples was achieved through principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). The model exhibited excellent performance, with the fit index of dependent variables (R2Y) and the predictive index of the model (Q2) values of 0.99 and 0.984, respectively. These results provided significant theoretical evidence for the application of HS-GC-IMS as an efficient technique in the analysis of volatile compounds, identification of positional isomers and functional group isomers, as well as tracing the origin of stamp-pad ink and analyzing the formation time of documents.

Influence of magnesium treatment on inclusions and primary carbides in As-cast H13 die steel

In this study, the inclusions and primary carbides in H13 hot-work tool steel were investigated, both with and without magnesium treatment, utilizing various analytical techniques such as optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and quantitative analysis methods. Furthermore, the experimental results were compared with the calculations obtained from Thermo-Calc software. The results revealed that as we move from the edge to the center of the steel, the equivalent diame-ter of inclusions increased. However, upon adding magnesium to the steel, the size of inclusions decreased, while the number of inclusions per unit area increased. The primary carbides found in H13 steel consisted of vanadium-rich MC carbides and molybdenum-chromium-rich M2C carbides. The addition of magnesium had a significant impact on the size of these primary carbides. The presence of MgAl2O4 particles acted as heterogeneous nuclei, providing nucleation sites that induced smaller sizes and more uniform distribution of primary carbides. Furthermore, it was observed that the banded segregation in the annealed microstructure became more uniform after magnesium treatment, leading to an improvement in the banded segregation.

Strategies for optimizing the single GdSrFeO4 phase synthesis

Abstract This work provides data on strategies for single GdSrFeO4 phase solid state synthesis. Earlier works have shown that under the solid-state synthesis conditions, the GdSrFeO4 preparation is hampered by the formation of non-target product: Gd2SrFe2O7. This work approach led to the solid-phase synthesis GdSrFeO4 scheme change. GdSrFeO4 was characterized by X-Ray, scanning electron microscopy/energy dispersive X-ray spectroscopy, dilatometry and complex thermal analysis methods. GdSrFeO4 is stable in the wide range of studied temperatures 40–1,400°C in air. The sintering start temperature was determined to be 985°C. GdSrFeO4 has a thermal expansion coefficient of 30 × 10−6 K−1. The thermal stability is excellent for further investigation and potential for application of the materials as SOFC, for example. The study of catalytic stability of the obtained GdSrFeO4 is to be a subject of future work as well.

Rapid classification and identification of chemical compositions of Pu-zhi-hui-ling decoction by UHPLC-Q-Orbitrap HRMS

Pu-zhi-hui-ling decoction (PZHLD) is a traditional Chinese medicine (TCM) formula for the treatment of Alzheimer’s disease (AD), but its chemical composition has not been reported. In this study, we aimed to establish a mass spectrometry (MS) analysis method for rapid classification and identification of the chemical constituents in PZHLD. The sample was analysed by ultrahigh-performance liquid chromatography coupled to quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). The chemical constituents of PZHLD were identified based on accurate MS data, fragmentation characteristics of MS/MS, and reference information described in the literature. A total of 123 chemical constituents were identified. In addition, we summarised the fragmentation pathways of the chemical constituents in PZHLD. Our finding might lay the foundation for the further pharmacodynamic study and clinical application of PZHLD.

Optimization of two-stage thermal desorption combined with pentafluorophenyl hydrazine derivatization-gas chromatography/mass spectrometry analytical method of atmospheric carbonyl compounds

The detection method of carbonyl compounds (CCs) in the atmosphere has been a challenging problem because of its low concentration and strong volatility and reactivity. Based on the existing thermal desorption (TD) technology, the TD instrument was combined with gas chromatography/mass spectrometry (GC/MS), and pentafluorophenyl hydrazine (PFPH) was used as derivatization reagent to establish a simple, high sensitivity, good stability and simultaneous detection of 13 atmospheric carbonyl compounds, namely PFPH derivation-two-stage TD-GC/MS analysis method. The main factors affecting the TD conditions were discussed, including desorption temperature, desorption time and carrier gas flow rate. The results showed that when the tube desorption flow rate and time were 10 mL min−1 and 8 min, and the trap desorption flow rate and time were 5 mL min−1 and 8 min, the recoveries of various CCs PFPH-derivatives were relatively high. The collection efficiencies of all detected carbonyls by this method were above 85 %. The method detection limits (MDLs) of the tested carbonyls were in the range of 0.44–1.23 ng cartridge−1. Compared with the method of PFPH-solvent desorption-GC/MS, the two-stage TD-GC/MS method showed lower MDLs and more carbonyls detected at low concentrations. In brief, the two stage TD-GC/MS analysis method is of great significance for the detection of trace CCs in the time-varying atmospheric environment, and is worthy of popularization and application in atmospheric samples.