冠瘤海鞘的化学成分

从中国惠州大亚湾海域采集的冠瘤海鞘的甲醇－氯仿提取物中分离出混合甾醇和神经酰胺两类化合物,混合甾醇经波谱分析和GC／MS联机分析,发现其主要由十种甾醇组成,含量为甲醇－氯仿提取物的12％。神经酰胺为十八碳酰基鞘氨醇,其结构通过波谱鉴定,含量为提取物的0.3%,这是有关冠瘤海鞘化学成分研究的首次报道。     

波谱分析在沙棘果多糖Hn结构研究中的应用

以波谱分析为主要手段研究沙棘果多糖Hn的结构，GC分析表明Hn由Ara，Gal，Man和Glc组成，单糖物质的量比与利用GC分析Hn甲基化产物的结果一致．^13C—NMR分析表明Hn中存在α，β型糖苷键．利用GC—MS分析进一步确定Hn主链结构由β（1→4）Glc，β（1→6）Man和β（1→4）Gal构成，在3-O处有分支，支链由α（1→4）Glc，（1→6）Gal或末端Ara，Glc构成．     

TLC-HPLC-Q-TOF-MS法快速鉴定柑橘提取物消毒液中桔皮素、蜜橘黄素、新橙皮苷和柚皮苷及其含量测定

建立了薄层色谱-高效液相色谱-四极杆飞行时间质谱法联用技术(TLC-HPLC-QTOF-MS)快速鉴定柑橘提取物消毒液中桔皮素、蜜橘黄素、新橙皮苷和柚皮苷4种活性物质并测定其含量的方法。样品经氯仿-丙酮洗脱剂梯度洗脱,TLC检识,半制备HPLC纯化,HPLCMS/MS鉴定及HPLC含量测定。结果表明,以氯仿-丙酮(3:1,V/V)作为展开剂分离效果最好。以甲醇-水(7:3,V/V)作为流动相测定桔皮素和蜜橘黄素的含量,以甲醇-0.2%乙酸(13:7,V/V)作为流动相对柚皮苷和新橙皮苷进行定性和定量分析,分离度及峰形最佳。方法测定桔皮素、蜜橘黄素、新橙皮苷和柚皮苷含量的相关系数均大于0.999,检测限分别为:0.3,0.1,0.4,1.2μg/mL,相对标准偏差分别为1.9%,1.9%,2.2%,1.5%,平均回收率分别为97.0%,103.5%,97.8%,100.1%。方法可用于柑橘提取物消毒液质量控制。     

环氧乙烷-四氢呋喃共聚醚中环状齐聚物的气相色谱/质谱分析

首先将环氧乙烷（EO）-四氢呋喃（THF）共聚醚与二异氰酸酯反应，然后将未反应的环状齐聚醚（OCE）用乙醚萃取出来。经气相色谱/质谱（GC/MS）联机分析，鉴定出12个主要峰的结构组成，占总峰面积的96.42%。其中环状四聚体和环状五聚体的含量较高。     

气相色谱/质谱法分析羊毛脂中的甾类化合物

羊毛脂（lanolin）是由羊皮脂腺分泌出而黏附于羊毛上的多组分混合物,主要是由多种羟基脂肪酸、脂肪酸与大致等量的脂肪醇、甾醇等所形成的酯和少量游离酸、游离醇以及烷烃所组成,其中的醇类统称为羊毛醇。本文采用气相色谱-质谱（GC—MS）分析了羊毛醇中的各组分,在分析过程中发现了两种未曾报道的甾类化合物。     

白音华褐煤可溶有机质的组成和结构特征

依次采用石油醚、环己烷、二硫化碳、丙酮、甲醇和等体积的丙酮/二硫化碳混合溶剂对白音华褐煤(BL)进行分级萃取得到萃取物(E_1-E_6),利用甲醇、甲苯和等体积的甲醇/甲苯混合溶剂对萃取残渣进行连续热溶得到热溶物(SP_1-SP_3)。利用傅里叶变换红外光谱(FT-IR)、气相色谱质谱(GC/MS)和实时直接分析-质谱(DART-MS)对萃取物和热溶物的组成和结构特征进行了分析。BL总的萃取物产率和热溶物产率分别为9.37%和21.84%。E_5和E_6的FT-IR谱图中有较强的羟基吸收峰,而E_1的FT-IR谱图中脂肪C-H的伸缩振动峰强度明显高于其他萃取物;三种溶剂热溶物的FT-IR谱图相似,但SP_1和SP_3的FT-IR谱图中羟基吸收峰较强。E_1和E_5中GC/MS可检测化合物分别以烷烃和芳烃为主,E_5中还含有较多的含氧化合物;三种热溶物中化合物均以烷烃和芳烃为主,SP_3中酚类、酮类和酯类等含氧化合物的含量较高。DART-MS可检测出萃取物和热溶物中GC/MS无法检测出的较强极性和难挥发化合物;热溶物中含量较高的化合物的碳数和等价双键数(Double bond equivalent,DBE)分别集中分布在10-25和2-16,并且DBE随碳数增加而增加。     

先锋褐煤可溶有机质中含氮化合物的组成和结构特征

先锋褐煤在高压釜中用等体积的甲醇/甲苯溶剂300℃下热溶得到热溶物和热溶残渣,利用X射线光电子能谱（XPS）分析了先锋褐煤及其热溶残渣中氮的形态,利用气相色谱/质谱（GC/MS）和电喷雾傅里叶变换-离子回旋共振质谱（ESI FT-ICR MS）分析了热溶物中含氮化合物的组成和结构特征。研究表明,先锋褐煤中氮形态含量顺序为季氮 > 吡啶氮 > 吡咯氮,而季氮在热溶过程中更易溶出。GC/MS共检测出热溶物中20种含氮化合物,并且大部分为胺类化合物。ESI FT-ICR MS检测出热溶物中300多种含氮化合物,大部分含氮化合物含一个或三个氮原子。含一个氮原子的含氮化合物主要以N₁O₁、N₁O₂和N₁O_xS_1-2类化合物为主,而含三个氮原子的含氮化合物主要以N₃O_xS_1-2（x=1-12）类化合物为主。含一个氮原子的含氮化合物的等效双键数和碳数随氧原子数增加而增加。     

小刺豆荚软珊瑚甾醇类化合物的提取、分离及鉴定

从西沙群岛海区采集的小刺豆荚软珊瑚（Lobophytummicrospiculatum）中,通过乙醇提取、乙酸乙酯-水分配、硅胶色谱分离和GC／MS分析等方法,分离、鉴定出11种甾醇。其中柳珊瑚甾醇（11）的质量分数占65.6％。22,24-二甲基-胆甾-5,22（23）-二烯-3β-醇（4）是首次从自然界发现的新化合物,它的发现为柳珊瑚甾醇的生源假说提供了进一步佐证。     

基于傅里叶变换红外光谱和气相色谱-质谱的未知涂料成分分析

采用傅里叶变换红外光谱法（FT－IR）和气相色谱－质谱法（GC－MS）定性分析了未知涂料的主要化学组成。将涂料恒温烘干成膜,剪裁成条状和碎片状,经乙腈、甲醇超声提取,四氢呋喃溶解后,分别取条状涂膜及其四氢呋喃不溶物进行FT－IR分析,结合吸收峰特征、谱库检索定性。结果表明,涂料成膜物质主要是丙烯酸酯。将涂料样品及其乙腈和甲醇提取液,分别进行GC－MS分析并结合保留指数、谱库及文献筛查定性。结果表明,涂料溶剂由2-乙基己醇、邻二甲苯、间二甲苯、苯乙酮等组成;可能的助剂成分主要包括1-甲基萘、棕榈酸甲酯、α-甲基苯乙烯、2,4-二叔丁基苯酚、2,4-二甲基-6-叔丁基苯酚、油酸酰胺等;甲基丙烯酸正丁酯、丙烯酸异辛酯是未知涂料中的聚合单体。     

快原子轰击质谱直接分析山核桃油中的混合甘油三酸酯

本文利用快原子轰击质谱(FABMS)直接测定山核桃油中未经任何前处理的混合甘油三酸酯,能获得其分子量和碎片结构信息,在GC和GC/MS分析的基础上。根据FABMS测得的分子量可推导出甘油三酸酯的组成和不同甘油三酸酯的含量。FABMS定量结果和GC、GC/MS测定结果及文献值相符。     

长枝沙菜乙醇-乙酸乙酯溶出物的化学成分

海洋药物具有显著的药理稳定性和强效性,毒副作用相对较小,对防治癌症、艾滋病、心脑血管病、老年病等疑难杂症具有独特的作用,已成为开发新药、特效药的主要方向之一。长枝沙菜(Hyphea Charoides Lamx.)属红藻门沙菜科,其微量元素含量丰富。本文首次对长枝沙菜的化学成分进行了研究,从中分离得到神经酰胺和甾醇两类具有较强生理活性的物质。     

A lipidomic platform establishment for structural identification of skin ceramides with non-hydroxyacyl chains

The stratum corneum (SC) is the outermost layer of skin that functions as a barrier and protects against environmental influences and transepidermal water loss. Its unique morphology consists of keratin-enriched corneocytes embedded in a distinctive mixture of lipids containing mainly ceramides, free fatty acids, and cholesterol. Ceramides are sphingolipids consisting of sphingoid bases, which are linked to fatty acids by an amide bond. Typical sphingoid bases in the skin are composed of dihydrosphingosine (dS), sphingosine (S), phytosphingosine (P), and 6-hydroxysphingosine (H), and the fatty acid acyl chains are composed of non-hydroxy fatty acid (N), α-hydroxy fatty acid (A), ω-hydroxy fatty acid (O), and esterified ω-hydroxy fatty acid (E). The 16 ceramide classes include several combinations of sphingoid bases and fatty acid acyl chains. Among them, N-type ceramides are the most abundant in the SC. Mass spectrometry (MS)/MS analysis of N-type ceramides using chip-based direct infusion nanoelectrospray-ion trap mass spectrometry generated the characteristic fragmentation pattern of both acyl and sphingoid units, which could be applied to structural identification of ceramides. Based on the MS/MS fragmentation patterns of N-type ceramides, comprehensive fragmentation schemes were proposed. In addition, mass fragmentation patterns, which are specific to the sphingoid backbone of N-type ceramides, were found in higher m/z regions of tandem mass spectra. These characteristic and general fragmentation patterns were used to identify N-type ceramides in human SC. Based on established MS/MS fragmentation patterns of N-type ceramides, 52 ceramides (including different classes of NS, NdS, NP, and NH) were identified in human SC. The MS/MS fragmentation patterns of N-type ceramides were characterized by interpreting their product ion scan mass spectra. This information may be used to identify N-type ceramides in the SC of human, rat, and mouse skin.     

Separation and characterisation of sphingoceramides by high-performance liquid chromatography-electrospray ionisation mass spectrometry

We developed a simple and reliable analytical method for the quantification and the characterization of ceramides extracted from biological samples by high-performance liquid chromatography (HPLC) coupled to electrospray ionisation tandem mass spectrometry (ESI/MS/MS). The chromatographic separation of analytes was carried out in a RP8 column, eluting with a methanol-water mixture in gradient elution mode. The separated lipids were detected by total ion monitoring and characterised by MS/MS spectra; quantitative analysis was performed by integrating the extracted ion peaks obtained in the negative ion mode. Good repeatability was obtained for retention time (0.3-2%), peak area ratio (A(S)/A(IS), 2-8%), as well as limit of detection (LOD, 5-26 pg) and quantification (LOQ, 13-53 pg). The method was validated for the analysis of N-palmitoyl-D-erythro-sphingosine (Cer16), N-stearoyl-D-erythro-sphingosine (Cer18), N-tetracosanoyl-D-erythro-sphingosine (N24:0, lignoceric ceramide, Cer24:0), and N-tetracos-15'-enoyl-D-erythro-sphingosine (N24:1, nervonic ceramide, Cer24:1), giving good results. Lipid mixtures, extracted from skin and epidermal cells, were analysed for their content of the studied ceramides.     

Profiling of human stratum corneum ceramides by means of normal phase LC/APCI–MS

The ceramides of the stratum corneum are critical to maintaining the epidermal barrier function of the skin. A number of skin diseases and disorders are known to be related to impairments of the ceramide pattern. Therefore, obtaining mass spectrometric profiles of the nine ceramide classes known to exist aids our understanding of the underlying molecular mechanisms, which should eventually lead to new diagnostic opportunities: for example, the mass spectrometric profiles of patients suffering from serious skin diseases such as atopic dermatitis and psoriasis can be compared to those of healthy controls. Previous work on mass spectrometric analysis of ceramides relied mostly on GC/MS after hydrolysis and derivatization. The introduction of ESI–MS and LC/ESI–MS has provided new options for directly analyzing intact ceramides. However, some of the ceramide classes are not accessible to ESI–MS. However, as shown in this work, these limitations of GC/MS and ESI-MS can be overcome using a new approach based on normal phase LC interfaced with APCI–MS. Separation and online detection of the stratum corneum ceramide classes became possible in one run. Ceramide species with C26 and/or C28 fatty acid chains were the most abundant ones in Cer [NP], Cer [NH], Cer [AP], and Cer [AH]. The main component of Cer [AS] was C16. The ω-esterified ceramide classes Cer [EOS], Cer [EOP] and Cer [EOH] contained mostly species with fatty acids >C30. This was also the case for Cer [NS], suggesting an analogy to the ω-esterified ceramides. In addition, evidence for a new ceramide class Cer [NdS] was found. This paper was presented at the 38th Annual Meeting of the German Society for Maa Spectrometry (DGMS) held in March 2005 in Rostock, Germany.     

Extraction and purification procedures for simultaneous quantification of phenolic xenoestrogens and steroid estrogens in river sediment by gas chromatography/ion trap mass spectrometry

A sensitive and simple method based on ultrasonication extraction with a hexane/acetone (2:1, v/v) mixture, followed by clean up of the extract by solid-phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) detection, has been developed and validated for the analysis of 20 estrogenic endocrine-disrupting chemicals (EEDCs) including phenolic xenoestrogens, synthetic and natural estrogens in river sediment. After extraction and purification, analytes are derivatised with a BSTFA/TMCS/pyridine (49:1:50, v/v/v) mixture and quantified by GC/MS. The GC/MS method involves switching between electron ionisation (EI) and chemical ionisation (CI); it also switches between selected ion storage and tandem mass spectrometry detection. The applicability of the method has been demonstrated by analysing extracts of French river sediments for which bioanalytical tests (in vitro) had already shown that they were impacted by estrogenic endocrine disrupters. The biological contribution of all the products detected in each sediment extract was compared to the estrogenic activity measured by bioassays.     

南中国海海藻叶托马尾藻的化学成分研究

采自南中国海的海藻叶托马尾藻用乙醇提取、乙酸乙酯－水分配后,乙酸乙酯相中的提取物经硅胶减压柱色谱分离得到甾醇和脂肪酸两大组分。用ＧＣ／ＭＳ联用技术对它们进行了分离和鉴定。通过硅胶快速柱色谱,从混合甾醇中分离出一个主成分,经波谱分析鉴定为岩藻甾醇。     

Mass spectrometric analysis of ceramide composition in mono-, di-, tri-, and tetraglycosylceramides from mouse kidney: an experimental model for uropathogenic Escherichia coli.

Many bacteria have been shown to bind to the carbohydrate part of glycosphingolipids, but also the lipid moieties of receptor-active glycolipids are of importance. To investigate the chemistry of the ceramides of kidney glycolipids to which the uropathogenic Escherichia coli bind, different mass spectrometric techniques were utilized. First, a mixture of glycolipids isolated from man and mice kidney was separated by thin-layer chromatography (TLC) and scanned by direct desorption from the plate by fast atom bombardment mass spectrometry (TLC/FAB-MS). Second, the glycolipids were purified by preparative TLC and analyzed by negative-ion FAB-MS. After methylation, further analyses were made with positive-ion FAB-MS, positive-ion electron ionization (EI)-MS, high-temperature capillary gas chromatography (GC/EI-MS) and positive-ion matrix-assisted laser desorption/ionization (MALDI)-MS. The ceramide compositions of the four glycolipids were determined using all these MS techniques and the reliability of the different methods for this type of analyses is discussed. Comparison of the mouse kidney glycolipids with the corresponding glycolipids from human kidney showed the same degree of hydroxylation of ceramides among mono- and disaccharide glycolipids, but a significantly higher degree of hydroxylation among mouse kidney glycolipids with three and four sugar residues. This result might be of relevance for the binding of P-fimbriated E. coli to the urinary tract tissues.     

A Glimpse of Recent Developments in Brazilian Analytical Chemistry

Geting bituminous coal (GBC) was exhaustively extracted with isometric carbon disulfide/acetone at ambient temperature to provide twenty extracts and a residue. The extracts were characterized by gas chromatography/mass spectrometry (GC/MS), Fourier transform infrared spectroscopy, and atmospheric pressure solids analysis probe time-of-flight mass spectrometry. GBC and its residue were observed with a scanning electron microscope. The total extract yield is ca. 11.5%. The GC/MS-detectable compounds in extract 1 can be classified into alkanes, cyclanes, arenes, cyclenes, and heteroatomic compounds, among which arenes are predominant. The number of detected compounds decreases and they have higher molecular masses with increasing extraction times. The combination of multiple techniques facilitates understanding the molecular composition of the extractable species from coals.     

Fragmentation of a novel marine peptide, plicatamide, involves an unusual gas-phase intramolecular rearrangement

During our characterization of plicatamide 1, a modified octapeptide: Phe-Phe-His-Leu-His-Phe-His-dc deltaDOPA (where dc deltaDOPA = decarboxy-(E)-alpha,beta-dehydro-3,4-dihydroxyphenylalanine) from the blood cells of the ascidian Styela plicata, we noted a series of fragment ions from the [M + H]+ ion which could not be assigned. There was no evidence in the 1H NMR spectrum to support an alternative molecular structure and the series of fragment ions were not present in the tandem mass spectrometry analysis of the [M + Na]+ ion. In addition, there was no evidence that the sample was a mixture of isobaric compounds. We propose that an unusual C-terminal to N-terminal rearrangement is responsible for the series of fragment ions from the [M + H]+ ion. This rearrangement was not observed in peptide analogs of plicatamide which did not contain the dc deltaDOPA at the C-terminus suggesting that this moiety is critical for the rearrangement. The proposed reaction is analogous to that recently reported by Vachet et al. involving a fragment ion formed from leucine enkephalin.