气相色谱法测定分子筛生产循环废水中的三乙胺及杂质含量

采用气相色谱-质谱仪对晶化母液处理回收工艺流程中的三乙胺及杂质含量进行了定性分析,确定了三乙胺的杂质种类,为建立气相色谱分析方法确立了目标组分。在筛选色谱柱和优化色谱条件的基础上,选用十六烷醇柱CP7448(0.32 mm×60 m×0.5μm),TCD检测器,测定回用三乙胺产品的纯度和杂质含量,实验结果表明,目标组分分离效果良好。以校正面积归一法对三乙胺及杂质的质量分数进行定量,各组分重复测定5次的相对标准偏差均小于1.8%,回收率在98.5%~103.0%之间,表明方法的精密度和准确度良好,并具有快速、可靠的特点。     

Physical Processes and Real-Time Chemical Measurement of the Insect Olfactory Environment

Odor-mediated insect navigation in airborne chemical plumes is vital to many ecological interactions, including mate finding, flower nectaring, and host locating (where disease transmission or herbivory may begin). After emission, volatile chemicals become rapidly mixed and diluted through physical processes that create a dynamic olfactory environment. This review examines those physical processes and some of the analytical technologies available to characterize those behavior-inducing chemical signals at temporal scales equivalent to the olfactory processing in insects. In particular, we focus on two areas of research that together may further our understanding of olfactory signal dynamics and its processing and perception by insects. First, measurement of physical atmospheric processes in the field can provide insight into the spatiotemporal dynamics of the odor signal available to insects. Field measurements in turn permit aspects of the physical environment to be simulated in the laboratory, thereby allowing careful investigation into the links between odor signal dynamics and insect behavior. Second, emerging analytical technologies with high recording frequencies and field-friendly inlet systems may offer new opportunities to characterize natural odors at spatiotemporal scales relevant to insect perception and behavior. Characterization of the chemical signal environment allows the determination of when and where olfactory-mediated behaviors may control ecological interactions. Finally, we argue that coupling of these two research areas will foster increased understanding of the physicochemical environment and enable researchers to determine how olfactory environments shape insect behaviors and sensory systems.     

Development of a Rapid Ultra High-Performance Liquid Chromatography/Tandem Mass Spectrometry Method for the Analysis of sn-1 and sn-2 Lysophosphatidic Acid Regioisomers in Mouse Plasma

Lysophosphatidic acids (lysoPtdOH) are involved in several physiological processes including cell proliferation, inflammation, and glucose metabolism. However, measuring lysoPtdOH is challenging due to inadequate extraction techniques, poor chromatographic resolution, or the inability to discriminate between sn-1 and sn-2 regioisomers. In the present work, we developed a high-throughput (10 min run times) ultra-high-performance liquid chromatography–tandem mass spectrometry method capable of discriminating lysoPtdOH species by their fatty acyl composition and sn-localization on glycerol backbones. We quantitated sn-1/sn-2 regioisomeric pairs of lysoPtdOH with 16:0, 18:0, 18:1, 18:2, 20:4, and 22:6 fatty acyl chains using 50 μL of mouse plasma. The method presented here can be expanded to profile more lysoPtdOH species, and has the potential to be used in clinical settings to quickly screen lysoPtdOH profiles. Finally, the ability to discriminate between sn-1 and sn-2 isomers can provide insights regarding the metabolic origins and fates of specific lysoPtdOH molecules.     

Transient Receptor Potential (TRP) Channels in the Pacific Oyster (Crassostrea gigas): Genome-Wide Identification and Expression Profiling after Heat Stress between C. gigas and C. angulata

Transmembrane proteins are involved in an array of stress responses, particularly in thermo-sensation and thermo-regulation. In this study, we performed a genome-wide identification and characterization of the Transient Receptor Potential (TRP) genes in the Pacific oyster (Crassostrea gigas) and investigated their expression profiles after heat stress to identify critical TRPs potentially associated with thermal regulation. A total of 66 TRP genes were identified in the C. gigas, which showed significant gene expansion and tandem duplication. Meta-analysis of the available RNA-Seq data generated from samples after acute heat stress revealed a set of heat-inducible TRPs. Further examination of their expression profiles under chronic heat stress, and comparison between C. gigas and C. angulata, two oyster species with different tolerance levels to heat stress, led to the identification of TRPC3.6, TRPC3.7, and TRPV4.7 as important TRPs involved in thermal regulation in oysters. This work provided valuable information for future studies on the molecular mechanism of TRP mediated thermal tolerance, and identification of diagnostic biomarker for thermal stress in the oysters.     

3-Alkyl-2-Methoxypyrazines: Overview of Their Occurrence,Biosynthesis and Distribution in Edible Plants

Pyrazines are ubiquitous in nature – biosynthesized by microorganisms, insects, and plants. Due to their great structural diversity, they own manifold biological functions. Alkyl- and alkoxypyrazines for instance play a key role as semiochemicals, but also as important aroma compounds in foods. Especially 3-alkyl-2-methoxypyrazines (MPs) have been of great research interest. MPs are associated with green and earthy attributes. They are responsible for the distinctive aroma properties of numerous vegetables. Moreover, they have a strong influence on the aroma of wines, in which they are primarily grape-derived. Over the years various methods have been developed and implemented to analyse the distribution of MPs in plants. In addition, the biosynthetic pathway of MPs has always been of particular interest. Different pathways and precursors have been proposed and controversially discussed in the literature. While the identification of genes encoding O-methyltransferases gave important insights into the last step of MP-biosynthesis, earlier biosynthetic steps and precursors remained unknown. It was not until 2022 that in vivo feeding experiments with stable isotope labeled compounds revealed l -leucine and l -serine as important precursors for IBMP. This discovery gave evidence for a metabolic interface between the MP-biosynthesis and photorespiration.     

碳酸二甲酯磺化试验色度偏大的气相色谱-质谱分析

针对碳酸二甲酯(DMC)产品磺化试验色度偏大问题,利用气相色谱-质谱联用技术分析,确定影响DMC产品磺化试验色度大的主要物质为甲苯、二甲苯及其同分异构体,且其含量越高,颜色越深,提出从源头控制该物质的引入,确保色度合格的建议。该实验目前在碳酸二甲酯行业属于首创。     

Sensory characterization and identification of odorous constituents in acrylic adhesives

Most products in our surroundings contain adhesives, including acrylic adhesives which are used in many industry sectors. Some of these adhesives contain solvents that produce strong odors, but even adhesives which are produced without solvents can emit intensive or pungent odors. In the latter case, the odor may arise from monomers in the adhesive product, from manufacturing by-products or from degradation products. Here we analyzed several acrylic, methacrylic and benzyl acrylic adhesives to identify representative odorous contaminants. The volatile fraction of the products was extracted and isolated by solvent-assisted flavor evaporation (SAFE), then analyzed via high-resolution gas chromatography olfactometry (HRGC-O), HRGC-mass spectrometry (HRGC-MS/O) and two-dimensional HRGC-MS/O. Aroma extract dilution analysis was carried out to determine the most prominent odorants. Using this targeted odorant-analytical approach, we identified 27 odorous substances representing diverse classes of molecules, including phenols with leather-like, horse stable-like or medicinal odors, acrylates eliciting glue-like, moldy and fruity impressions, and different esters with honey-like or effervescent tablet-like smells. These results show that the odor of acrylic adhesives results from a mixture of different odorants that cannot generally be traced back to the main constituents of the product but are rather likely to stem from impurities and trace side products and other contaminants.     

Rapid Quantitative Determination of Squalene in Shark Liver Oils by Raman and IR Spectroscopy

Squalene is sourced predominantly from shark liver oils and to a lesser extent from plants such as olives. It is used for the production of surfactants, dyes, sunscreen, and cosmetics. The economic value of shark liver oil is directly related to the squalene content, which in turn is highly variable and species‐dependent. Presented here is a validated gas chromatography‐mass spectrometry analysis method for the quantitation of squalene in shark liver oils, with an accuracy of 99.0 %, precision of 0.23 % (standard deviation), and linearity of >0.999. The method has been used to measure the squalene concentration of 16 commercial shark liver oils. These reference squalene concentrations were related to infrared (IR) and Raman spectra of the same oils using partial least squares regression. The resultant models were suitable for the rapid quantitation of squalene in shark liver oils, with cross‐validation r² values of >0.98 and root mean square errors of validation of ≤4.3 % w/w. Independent test set validation of these models found mean absolute deviations of the 4.9 and 1.0 % w/w for the IR and Raman models, respectively. Both techniques were more accurate than results obtained by an industrial refractive index analysis method, which is used for rapid, cheap quantitation of squalene in shark liver oils. In particular, the Raman partial least squares regression was suited to quantitative squalene analysis. The intense and highly characteristic Raman bands of squalene made quantitative analysis possible irrespective of the lipid matrix.     

Preparation and Characterization of Oil Rich in Odd Chain Fatty Acids from Rhodococcus opacus PD630

Odd-chain fatty acids (OCFA) are widely used in pharmaceutical and food industries, as well as the chemical industry. In this study, oil rich in OCFA was produced by Rhodococcus opacus PD630, and 1-propanol in combination with glucose was used as the carbon and energy source. Oil was extracted by the subcritical extraction system. Gas chromatography (GC), ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), and differential scanning calorimetry (DSC) were used to evaluate the fatty acids composition, triacylglycerol (TAG) molecular species, and thermal properties, respectively. It was found that the content of OCFA reached 68.15%, where pentadecanoic acid (7.74%), heptadecanoic acid (18.20%), and heptadecenoic acid (42.71%) were the dominant OCFA. The most abundant TAG were HePaHa (15.82%), HePHa (11.42%), HePaHe (9.68%), HeHaHa (9.62%), HePaO (8.26%), and HePPa (8.00%). In terms of thermal profiles, recrystallization was detected in the oil rich in OCFA. Above all, these findings greatly extend the utilization of the microbial oil rich in OCFA, and they may have a significant impact on the future development of the microbial oil industry.     

Cistus ladanifer L. Shrub is Rich in Saturated and Branched Chain Fatty Acids and their Concentration Increases in the Mediterranean Dry Season

The Cistus ladanifer L. shrub is a widespread species of the Mediterranean region that is available as a feed source for ruminants all the year round, constituting a source of energy and nutrients when most of the vegetation is dry. However, there is no trustworthy information about the fatty acid composition of C. ladanifer, as well as no information about the seasonal and age related changes in their fatty acid composition. Thus, we collected the aerial parts of C. ladanifer plants of two age groups [young vs. older ones (2–6 years old)] during four consecutive seasons to characterize their fatty acid composition. The fatty acid composition of C. ladanifer is dominated by saturated fatty acids including the occurrence of two methyl branched chain fatty acids (BCFA), the iso‐19:0 and iso‐21:0, which as far as we know were detected for the first time in shrubs. Also, we demonstrated that several labdane type compounds might interfere with the fatty acid analysis of C. ladanifer. Marked seasonal changes in BCFA and polyunsaturated fatty acids (PUFA) were found, suggesting that BCFA can replace PUFA in plant lipids at high environmental temperatures.     

Separation Behavior of Octadecadienoic Acid Isomers and Identification of cis‐ and trans‐Isomers Using Gas Chromatography

Using a strongly polar cyanopropyl capillary column we have investigated the gas chromatography (GC) separation behaviors of 24 octadecadienoic acid methyl ester (18:2ME) isomers compared against saturated methyl stearate (18:0ME) and arachidic acid methyl ester (20:0ME), and the dependency on the GC column temperature. The 24 isomers were obtained by performing cis‐to trans‐isomerization of six regioisomers: five of the 18:2ME isomers were prepared by the partial reduction of methyl α‐linolenate and methyl γ‐linolenate C18 trienoic acids with different double bond positions, whereas the sixth isomer, 18:2ME (c5, c9), was obtained from a raw constituent fatty acid methyl ester (FAME) sample extracted from Japanese yew seeds. There are no reference standards commercially available for 18:2ME isomers, and in elucidating the elution order of these isomers this study should help the future identification of cis‐ and trans‐type of 18:2ME. We also report the identification method of cis‐ and trans‐type of FAME using equivalent chain lengths and attempt the identification of cis‐ and trans‐type of 18:2ME isomers from partially hydrogenated canola oil.     

Development of the Method for Nusinersen and Its Metabolites Identification in the Serum Samples of Children Treated with Spinraza for Spinal Muscular Atrophy

The application of oligonucleotides as drugs for different genetic diseases is increasing rapidly. Since 2016 they are used during spinal muscular atrophy treatment with the use of nusinersen oligonucleotide. The purpose of this study was to improve methods for the analysis of serum samples of patients treated with nusinersen. The results showed that liquid-liquid extraction (with phenol/chloroform) is insufficient and an additional purification step using solid-phase extraction is necessary. The best results were obtained for microextraction by packed sorbents. Important parameters in the optimization of the method were mainly the type of amine in the mobile phase and the stationary phase. Both influenced the selectivity of metabolite separation and thus their correct identification; while amine type impacted also the intensity of signals. Finally, the highest resolution of separation and the highest peak areas were obtained for N,N-dimethylbutylamine or N,N-diisopropylthylamine with an octadecyl column with a terminal aryl group. Over a dozen of metabolites were successfully identified with the use of methods developed during the study. The 3′ exonucleases and 5′ exonucleases were mainly responsible for nusinersen metabolism, consequently, 3′end shortmers, and 5′end shortmers were observed, as well as metabolites with simultaneous loss of bases at both ends of the sequence. However, some depurination and depyrimidination products were also identified. To the best of our knowledge, this is the first report on nusinersen and its metabolite identification in serum samples by liquid chromatography and mass spectrometry.     

液相色谱与质谱联用技术在药物分析中的应用

综述了液相色谱及质谱联用技术近年的发展和在药物分析中的应用,指出该技术已成为药物研究和质量控制的最有效手段之一。     

液相色谱及液质联用技术在环境分析中的应用

高效液相色谱（HPLC）是在经典液相色谱法和气相色谱法的基础上发展起来的新型分离分析技术。20世纪80、90年代后,HPLC技术发展迅速,特别是21世纪初,液相色谱与现代质谱的联机技术有了很大的发展,使HPLC的应用前景更为广阔。在全部已知的有机化合物中近80％的有机化合物属于挥发性低,易受热分解或者大分子化合物,适合于高效液相色谱进行分析。本文主要从HPLC分析方法的特点为切入点,介绍液相色谱及液质联用技术在环境分析中的应用。     

气相色谱分析技术在焦化工业中的应用进展

综述了近年来气相色谱技术在焦化工业分析方面的应用,包括:回收系统气相色谱分析、焦油加工系统气相色谱分析、环保领域气相色谱分析等。对比分析了各方法的要点和特点,并结合宣钢焦化厂的应用情况及作者的工作实践进行了评述。     

Identification and quantification of important steryl esters in aspen wood

Steryl esters make up a major portion of the total lipids in aspen wood, and contribute significantly to pitch deposit problems during pulping. Fungal treatment of aspen is an attractive method for removing these compounds because it is inexpensive and environmentally acceptable; however, the mechanism of steryl ester removal remains unclear. Identification of the steryl esters will lead to a better understanding of how they are removed by fungi. The steryl ester fraction from aspen wood was obtained by acetone extraction then further purified by silica gel column chromatography and argentation-silica gel column chromatography. This led to the isolation of three major fractions: fraction I, fraction II, and fraction III. The major steryl esters of fractions I and II were identified by gas chromatography, gas chromatography-mass spectroscopy, and proton nuclear magnetic resonance analysis of the intact fraction as well as sterol and fatty acid moieties obtained after base hydrolysis. Identification of the steryl esters was carried out by mass spectra comparisons with steryl ester standards synthesized in the laboratory and comparison with mass spectra libraries (Wiley and NIST) by mass fragmentography. Fraction I contained primarily the palmitate, stearate, and eicosanoate esters of α- and β-amyrin. Fraction II consisted mainly of the palmitate, stearate, and eicosanoate esters of tirucalla-7,24-dien-3β-ol and lupeol.     

离子液体在分离分析中的应用

离子液体是在室温或室温附近温度下为液态且完全由离子构成的新型溶剂。具有很多独特的性质,已成功应用于分离分析的各个领域。文中综述了室温离子液体在气相色谱、液相色谱、光谱分析等领域的应用。     

气相色谱/质谱法在环境水样分析中的应用

使用树脂吸附、溶剂洗脱、GC/MS联用技术对某地一化工厂向河流中直接排放的废水、河流的上河水和下河水及地下水进行了分析和检验,检测出样品中所含的数十种有机化合物。该方法快速、灵敏,且定性定量准确,为行政管理部门实施监督和管理,工厂对排放水进行控制和处理及工厂周围居民对所饮用水的水质了解,提供了有效的途径和依据。     

Cholesterol Stationary Phase in the Separation and Identification of siRNA Impurities by Two-Dimensional Liquid Chromatography-Mass Spectrometry

The aim of this research was to develop a simple and efficient ion-pair reagent-free chromatographic method for the separation and qualitative determination of oligonucleotide impurities, exemplified by synthesis of raw products of the two single strands of patisiran siRNA. The stationary phases with mixed hydrophobic/hydrophilic properties (cholesterol and alkylamide) were firstly used for this purpose with reversed-phased high-performance liquid chromatography. Several different chromatographic parameters were tested for their impact on impurities separation: type, concentration, pH of salt, as well as organic solvent type in the mobile phase. The pH was the most influential factor on the separation and signal intensities in mass spectrometry detection. Finally, the optimized method included the application of cholesterol stationary phase, with mobile phase containing 20 mM ammonium formate (pH 6.5) and methanol. It allowed good separation and the identification of most impurities within 25 min. Since not all closely related impurities could be fully resolved from the main peak in this oligonucleotide impurity profiling, two-dimensional liquid chromatography was used for peak purity determination of the target oligonucleotides. The Ethylene Bridged Hybrid (BEH) Amide column in hydrophilic interaction liquid chromatography was applied in the second dimension, allowing additional separation of three closely related impurities.     

Genome-Wide Identification and Analysis of the Metallothionein Genes in Oryza Genus

Metallothionein (MT) proteins are low molecular mass, cysteine-rich, and metal-binding proteins that play an important role in maintaining metal homeostasis and stress response. However, the evolutionary relationships and functional differentiation of MT in the Oryza genus remain unclear. Here we identified 53 MT genes from six Oryza genera, including O. sativa ssp. japonica, O. rufipogon, O. sativa ssp. indica, O. nivara, O. glumaepatula, and O. barthii. The MT genes were clustered into four groups based on phylogenetic analysis. MT genes are unevenly distributed on chromosomes; almost half of the MT genes were clustered on chromosome 12, which may result from a fragment duplication containing the MT genes on chromosome 12. Five pairs of segmental duplication events and ten pairs of tandem duplication events were found in the rice MT family. The Ka/Ks values of the fifteen duplicated MT genes indicated that the duplicated MT genes were under a strong negative selection during evolution. Next, combining the promoter activity assay with gene expression analysis revealed different expression patterns of MT genes. In addition, the expression of OsMT genes was induced under different stresses, including NaCl, CdCl₂, ABA, and MeJ treatments. Additionally, we found that OsMT genes were mainly located in chloroplasts. These results imply that OsMT genes play different roles in response to these stresses. All results provide important insights into the evolution of the MT gene family in the Oryza genus, and will be helpful to further study the function of MT genes.