Molecular analysis of semen-like odor emitted by chestnut flowers using neutral desorption extractive atmospheric pressure chemical ionization mass spectrometry

Accelerated Oxidative Degradation of Phosphonium-Type Ionic Liquid with l-Prolinate Anion: Degradation Mechanism and CO2 Separation Performance

Amino acid ionic liquids (AAILs) are regarded as green alternatives to existing CO₂-sorptive materials because amino acids are readily available from renewable sources in large quantities. For widespread applications of AAILs, including direct air capture, the relationship between the stability of AAILs, especially toward O₂, and the CO₂ separation performance is of particular importance. In the present study, the accelerated oxidative degradation of tetra-n-butylphosphonium l-prolinate ([P₄₄₄₄][Pro]), a model AAIL that has been widely investigated as a CO₂-chemsorptive IL, is performed using a flow-type reactor system. Upon heating at 120-150 °C and O₂ gas bubbling to [P₄₄₄₄][Pro], both the cationic and anionic parts undergo oxidative degradation. The kinetic evaluation of the oxidative degradation of [P₄₄₄₄][Pro] is performed by tracing the decrease in the [Pro]^- concentration. Supported IL membranes composed of degraded [P₄₄₄₄][Pro] are fabricated, and the membranes retain CO₂ permeability and CO₂/N₂ selectivity values in spite of the partial degradation of [P₄₄₄₄][Pro].

Combination of Internal Extractive Electrospray Ionization Mass Spectrometry and Statistical Analysis for High-Throughput Molecular Differentiation of Rehmannia glutinosa Samples

Rehmannia glutinosa (Gaert.) Libosch. ex Fisch. et Mey. is a perennial herb of the Scrophulariaceae family, which has long enjoyed a good reputation in China, and has a wide range of pharmacological effects and clinical applications. The place of origin is an important factor affecting the chemical composition of R. glutinosa, resulting in different pharmacological effects. Herein, internal extractive electrospray ionization mass spectrometry (iEESI-MS) combined with statistical techniques was established for high-throughput molecular differentiation of different R. glutinosa samples. Dried and processed R. glutinosa samples from four different places of origin were analyzed by iEESI-MS with high throughput (>200 peaks) and rapidness (<2 min/sample) without sample pretreatment. Clear separation models created by OPLS-DA were then established for distinguishing the places of origin of dried and processed R. glutinosa by using the obtained MS data. In addition, the molecular differences between the pharmacological effects of dried and processed R. glutinosa were also investigated by OPLS-DA, and 31 different components were screened out. This work provides a promising method for evaluating the quality of traditional Chinese medicines and studying the biochemical mechanism of processing.

Molecular differentiation of Panax notoginseng grown under different conditions by internal extractive electrospray ionization mass spectrometry and multivariate analysis

Panax notoginseng is a highly valuable and widely used herb in traditional Chinese medicine. The quality and efficacy of Panax notoginseng grown under different conditions can greatly vary due to the differences in chemical composition. The analysis of chemical composition in Panax notoginseng typically involves various experimental steps including extraction, chromatographic separation and characterization, which can be time- and labor-consuming. Therefore, the efficient quality assessment and control of Panax notoginseng requires the development of more rapid methods for the chemical characterization and classification of Panax notoginseng. In this study, a method based on internal extractive electrospray ionization mass spectrometry (iEESI-MS) was developed to characterize chemical components of Panax notoginseng samples under different growth conditions (e.g., place of origin, soil quality, growth season) at the speed of 0.5 min per sample, without sample pretreatment and chromatographic separation. A total of 35 chemical components, including sugars, saponins, organic acids, etc., were identified in Panax notoginseng samples. Clear separation was observed in the multivariate analysis of the iEESI-MS data from Panax notoginseng samples grown under different conditions. The difference in the content of sucrose, fructose, Rg1, Rf, Rb1, Noto-R1, malonyl-Rb1, malonyl-Rg1, malonyl-Rf, Rd, Re, linoleic acid, palmitic acid and malic acid can be used as key characteristic indicators to discriminate origin, commercial specifications, and cultivation conditions of Panax notoginseng samples. The results of our study indicate the high power of iEESI-MS for the rapid molecular characterization and classification of Panax notoginseng under different growth conditions, which can be used for the quality assessment of traditional herbal medicines as well as in pharmaceutical and clinical analysis.

Rapid and sensitive detection of acetone in exhaled breath through the ambient reaction with water radical cations

The levels of acetone and other ketones in exhaled human breath can be associated with various metabolic conditions, e.g. ketosis, lung cancer, dietary fat loss and diabetes. In this study, ketones in breath samples were charged through the reaction with water radical cations to form [M + H₂O]˙⁺ ions, which were detected by mass spectrometry. Our experimental data indicate that under the optimized experimental conditions, the limit of detection for acetone using our approach is 0.14 ng L^-1 (∼0.06 ppb). The linear dynamic range of detection spans four orders of magnitude. The developed approach was applied to real-time semi-quantitative analysis of acetone in the exhaled breath of human volunteers, revealing significantly higher levels of acetone in the breath of smokers compared to non-smokers. The developed approach features the obviation of sample collection, easy operation, high speed of analysis (10 s per run), high sensitivity, and spectral interpretation, which indicates the potential of ambient corona discharge ionization mass spectrometry as a selective, sensitive and noninvasive technique for the determination of exhaled ketones in clinical diagnosis including lung cancer, diabetes, etc.

Comparison of Biochemical Constituents and Contents in Floral Nectar of Castanea spp

Pollination is essential for efficient reproduction in pollinator-dependent crops that rely on the attraction of pollinators to flowers. Especially, floral nectar is considered to be an important factor attracting pollinator like honey bees, but differences among major chestnut species (Castanea crenata, C. mollissima, C. dentata, and C. sativa) are still little explored. This study aims to evaluate the value of honey source by analyzing floral nectar characteristics and comparing the composition of volatile organic compounds (VOCs) that mediate plant-pollinator interaction. In this study, we analyzed nectar samples obtained from male flowers using HPLC and HS-SPME/GC-MS. The five chestnuts showed significant differences between the volume of secreted nectar, free sugar composition, amino acid content and VOCs composition. Furthermore, C. crenata (Japanese cultivar 'Ungi') was revealed to emit the highest total amounts of VOCs and high levels of benzenoid compounds that are generally associated with flower-visiting insects. The sugar content per catkin, which is used to determine the honey yield, was the highest in C. crenata, suggesting that C. crenata 'Ungi' can be highly valued as a honey tree. Therefore, a better understanding of the relationship between pollinator and nectar characteristics of C. crenara could contribute to a prospective honey plant.