聚环氧丙烷的电喷雾质谱分析

采用电喷雾质谱（ESI—MS）分析得到了聚环氧丙烷（PPO）的一级质谱和二级质谱。通过正负2种离子化模式计算一级质谱中各分子离子峰m／z的差值为58,证实了单体为环氧丙烷（PO）。并在二级质谱中通过对一些化合物碎片峰的解析,得到了PPO的裂解方式。同时利用碎片分析,推断出此PPO起始剂为丙三醇。     

顶空气相色谱/质谱法测定香精香科中丁二酮

采用气相色谱-质谱(GC-MS)分析技术,选择离子检测法(SIM),建立了香精香料中丁二酮的测定方法。色谱柱为DB-1 MS石英毛细管柱,电子轰击离子源,选择质谱图中的m/z 43和862个特征离子用于SIM检测,根据这2个离子的抽出离子色谱图的峰面积比进行目标物确证,以基峰m/z 86作定量分析,检出限为0.1 mg/kg。用色谱保留时间、质谱特征离子同时定性,消除了香精样品中复杂基体的干扰,避免了假阳性结果的出现。     

血中非那西丁的GC/MS检测

建立了非那西丁的气相色谱/质谱/质谱(GC/MS/MS)联用检测血中去痛片的主要代谢物非那西丁的新方法。采用液液提取法,用乙醚提取血中非那西丁,提取物水浴浓缩后进行GC/MS和GC/MS/MS分析,检测总离子流色谱(TIC)和一级质谱,并以非那西丁一级质谱基峰为母离子的测定其二级质谱,体内药物用GC/MS全扫描定性分析即用二级质谱结合其总离子流色谱峰的保留时间定性;选择离子扫描定量分析,采用内标曲线法,根据非那西丁和内标SKF525A二级质谱的TIC峰面积比进行定量分析。     

YZ-1菌株降解DBT代谢产物的GC-MS分析

从油污土壤中分离得到可脱除二苯并噻吩（DBT）的红串红球菌菌株（Rhodococcus erythropolis）YZ-1，利用气相色谱质谱连用仪（GC-MS）分析了YZ-1降解DBT的代谢产物，气相色谱（GC）分析代谢产物得到了3个化合物的色谱峰，保留时间分别为：22．55min、24．53min和20．14min。对3个峰分别离子扫描：保留时间为22．55min的峰对应的基峰m／z为184，经分析该化合物为DBT；保留时间为24．53min的峰对应的基峰m／z为216，经分析该化合物为二苯并噻吩砜（DBTO2）；保留时间为20．14min的峰的对应基峰m／z为141，经分析该化合物为2-羟基联苯（2-HBP）。根据生物催化脱硫的“4S”代谢途径，DBT02和2-HBP分别为微生物代谢DBT的中间产物和最终产物。BaCl2测试表明，DBT中的硫原子最终被YZ-1代谢为水溶性的硫酸盐。     

血中非那西丁的GC/MS检测

建立了非那西丁的气相色谱/质谱/质谱(GC/MS/MS)联用检测血中去痛片的主要代谢物非那西丁的新方法。采用液液提取法,用乙醚提取血中非那西丁,提取物水浴浓缩后进行GC/MS和GC/MS/MS分析,检测总离子流色谱(TIC)和一级质谱,并以非那西丁一级质谱基峰为母离子的测定其二级质谱,体内药物用GC/MS全扫描定性分析即用二级质谱结合其总离子流色谱峰的保留时间定性;选择离子扫描定量分析,采用内标曲线法,根据非那西丁和内标SKF525A二级质谱的TIC峰面积比进行定量分析。     

DCBI-MS法用于厚朴药材中厚朴酚与和厚朴酚裂解机制的研究

开发一种超快速的质谱方法用于厚朴药材中厚朴酚与和厚朴酚裂解机制的研究。采用解吸附电晕束离子源-质谱(DCBI-MS)进行分析检测,并采集二级质谱(MS~2)信号。DCBI质谱条件:毛细管温度250℃,分辩率1 Hz,质谱正离子模式,氦气流速1.5 mL/min,加热温度120℃,电流30μA,质量范围:m/z 100～1000;选择m/z=266,267作为母离子,MS~2裂解后得到二级离子碎片,确定m/z=266为厚朴酚与和厚朴酚的准分子离子峰,探究厚朴酚与和厚朴酚(同分异构体)的裂解规律。     

槲皮素苯甲酸酯的合成与表征

以槲皮素为原料、浓硫酸作催化剂,85℃与苯甲酰氯反应,TLC板监测反应完毕,过滤、氯仿/甲醇重结晶合成标题化合物。UV表征显示,槲皮素的两个特征吸收峰均发生蓝移,这是形成新化合物共轭体系引起的。IR中ν—OH峰明显减弱,说明槲皮素的5个羟基中有的羟基发生了反应;νCO位于1 745.32 cm-1,酯羰基峰明显增强;νC—O位于1 259.66cm-1,峰变宽增强。1HNMR中3-OH、3'-OH、4'-OH上面的氢消失,说明与苯甲酰氯发生了酯化反应;同时,在δ6.7~8.4处有苯甲酰基的多重峰。MS中m/z 615.2为槲皮素三苯甲酸酯的分子离子峰。因此,槲皮素与苯甲酰氯反应可以得到标题化合物。     

芦丁一锅煮合成槲皮素五乙酸酯

以芦丁为原料,浓硫酸作为催化剂,65℃与乙酸酐反应,薄层色谱法(TLC)板监测反应完毕,过滤,氯仿/甲醇重结晶,可以得到槲皮素五乙酸酯。结果显示:IR中ν—OH峰明显减弱,说明槲皮素的五个羟基发生了反应,νC=O位于1 776.0cm~(-1),酯羰基峰明显增强,νC—O位于1 199.0cm~(-1)、变宽增强;1 H NMR中3-OH、5-OH、7-OH、3′-OH、4′-OH上面的氢全部消失,说明与乙酸酐发生了酯化反应,同时,出现五组乙酰基的甲基峰;MS中m/z:513.1为槲皮素五乙酸酯的分子离子峰。     

液相色谱-串联质谱法测定烟叶中的玉米赤霉烯酮

建立了液相色谱-串联质谱法测定烟叶中玉米赤霉烯酮的方法。样品经无水乙醚提取,正己烷净化,采用多反应检测扫描方式(MRM),ESI负离子模式,确定了玉米赤霉烯酮的分子离子峰为(m/z)317.30,定量离子为(m/z)175.15,定性离子为(m/z)131.10,273.25。玉米赤霉烯酮在0～10ng/mL范围内线性关系良好(R0.999),方法检出限为0.42μg/kg;平均回收率为96.4%～101.1%,日内精密度RSD为2.5%,日间精密度RSD为9.05%。采用该方法满足烟叶中玉米赤霉烯酮的低含量检测。     

有机质谱学基础(二)

三、有机质谱中离子的类型及其和分子结构的关系当一种有机化合物进入质谱计后,经电子束的轰击,可以生成各种类型的离子,简单地表示即: 过程(1)形成分子离子;过程(2)到(5)形成碎片离子;过程(6)为重排后得到的碎片;过程(7)为分子离子和分子碰撞后产生的离子,这种离子大于原来的分子。分子离子和分子的碰撞是属于二级反应,在通常所用的样品压力下,这一反应可以忽视。因而在一张质谱图中一般会出现分子离子峰、碎片离子峰、重排离子峰,此外还会出现由同位素引起的同位素峰和由亚稳跃迁引起的亚稳峰。     

AB_2型β-环糊精功能单体的合成

分别对-β环糊精(CD)上6位伯羟基和2位仲羟基进行功能化改性,通过硅氢加成和麦克尔加成反应合成了带有硅氢键和双键的AB2型-βCD功能单体;并采用1H NMR、飞行时间质谱和元素分析对该功能单体的结构进行了表征。实验结果表明,该功能单体的结构与设计结构相符合,其m/z值为1 590.2。     

Analysis of fatty acids by mass spectrometry in the selected ion monitoring mode

GC/EI‐MS‐SIM (gas chromatography / electron ionisation – mass spectrometry with selected ion monitoring) can be easily applied to the determination of fatty acids as methyl esters (FAME). SIM masses should have a high relative abundance and for this reason we suggest m/z 74 and m/z 87 for saturated and monoenoic fatty acids as well as m/z 79 and m/z 81 for FAME with more than one double bond. The relevance and ratio of these fragment ions along with GC retention times enables a good identification of a FAME represented by a peak detected in the chromatograms. Compared to GC with a flame ionisation detector, this simple method provides a higher selectivity and better sensitivity. It also offers the possibilities of using a wide range of internal standards which enables the individual quantification of FAME instead of the determination of their contributions to the fatty acid pattern.     

Detection of hydroxy fatty acids in biological samples using capillary gas chromatography in combination with positive and negative chemical ionization mass spectrometry

The most common method for use in the structural analysis of hydroxy fatty acids in biological samples is the gas chromatography-mass spectrometry (GC-MS) analysis of trimethylsilyl ethers of the methyl esters using electron impact ionization. A comparison of electron impact (EI) with chemical ionization mass spectrometry (CI-MS) shows that CI-MS is the superior technique. All ions necessary for structural analysis are observed at sufficiently high levels of intensity when methane or isobutane are used as reactant gases. The molecular weight can be determined from the ion group M+H, M-15 and M+H−90. The ionic series M+H−n×90 enables one to determine the number of hydroxyl groups. The position of the hydroxyl groups can be derived from the fragments of the α-cleavage of the fatty acid chain. The application of heptafluorobutyrates as derivatives for hydroxy fatty acid methyl esters shows advantages in the trace analysis of these compounds. Heptafluorobutyrates exhibit useful mass fragmentation patterns in the positive as well as in the negative CI mode. With methane as the reactant gas, M+H usually is base peak in positive mass spectra. The ionic series M+H−n×214 leads to the number of hydroxy groups in the molecule. In the negative mass spectra, M and M-20 are indicative for the molecular weight. The ion group m/z 213, 194 and 178 at high levels of intensity is typical for heptafluorobutyrates. The advantage of the application of heptafluorobutyrates is the high sensitivity which can be obtained in trace analysis using negative MS. Heptafluorobutyrates of hydroxy fatty acids gave a 20-fold higher response in the negative scan mode compared to that of the positive. The detection limit for heptafluorobutyrates in negative CI-MS was on the order of 1 fg (10⁻¹⁵ g).     

GC-MS/MS法分析日化产品中三氯生

建立了三重四极杆气相色谱-质谱联用(GC-MS/MS)分析日化产品中三氯生的方法.用乙酸乙酯提取三氯生,优化了仪器条件、考察了基质效应,采用多反应监测(MRM)技术,对三氯生进行了定性定量分析,以三氯生离子对m/z 290＞218、m/z290＞ 148离子对进行定性,以n/z290＞ 148进行定量.方法在0.010...     

High-Molecular-Weight Polycyclic Aromatic Hydrocarbons in the Area and Vicinity of the Deza Chemical Plant,Czech Republic

Polycyclic aromatic hydrocarbons (PAHs) with molecular weight exceeding 278 amu were analyzed in air, water, and soils from the area and vicinity of the DEZA Chemical Plant (Vala w ské Mezi q í ) í, Czech Republic). Air and water were sampled using semipermeable membrane devices (SPMDs); grab sampling was applied for soils. Laser desorption/ionization-time-of-flight mass spectrometry (LDI-TOF MS) and liquid chromatography/ion trap mass spectrometry with atmospheric pressure chemical ionization (LC/APCI-ITMS) were employed for the quick assessment of PAH distribution and for the identification and quantification of some high-molecular-weight PAHs. Compounds with molecular mass up to 450 u were found. LDI-TOF mass spectra and selected LC/APCI-ITMS profiles (m/z 303, m/z 327, and m/z 351) were compared to identify potential source of contamination in this locality. High-molecular-weight PAHs were found in all environmental compartments in the area studied; their levels were quite high close to their source and decreased sharply with increasing distance from it.     

新显色剂2-(2-喹啉偶氮)-5-二乙氨基苯甲酸的谱学性质研究

分析、研究了新显色试剂2-(2’-喹啉偶氮)-5-二乙氨基苯甲酸(QADEAB)的红外吸收光谱、核磁共振氢谱和质谱等的谱学特性,并对其基峰以及主要碎片离子形成的机制和裂解规律进行了解析与探讨。     

Analysis of sterol esters by capillary gas chromatography-electron impact and chemical lonization-mass spectrometry

Synthetic mixtures of C₄₀ to C₄₇ sterol esters in groups of 7 esters were effectively separated and analyzed by capillary gas chromatography-mass spectrometry. Ammonia chemical ionization of all 20 sterol esters analyzed at a source block temperature of 120 C yielded (M+NH₄)⁺ and (M+H-RCO₂H)⁺ ions of high abundance or as base peak, thereby indirectly indicating the molecular weights of the ester and the sterol and acid moieties. Ammonia CI spectra of all esters containing a Δ⁵-sterol moiety exhibited in addition to the above 2 ions an M+NH₄-RCO₂ H fragment. At a source block temperature of 150 C, M+H-RCO₂ H fragment was the base peak for all esters, and there was little or no indication of an (M+NH₄)⁺ adduct ion. Protonated molecules were not observed for any esters analyzed by methane or isobutane CI. Molecular ions of 3–14% intensity were obtained for only 3 of the esters analyzed by electron impact; they contained a Δ⁷-bond in the sterol nucleus, and the acid moiety was either saturated normal or branched chain or contained a single double bond. The base peak was a function of both the acid and sterol moieties of the sterol ester. The esters containing both saturated straight chain acid and saturated sterol moieties exhibited a base peak at m/z 215. The Δ⁵-sterol esters with saturated branched or straight chain acid moieties exhibited base peaks at M-RCO₂ H. Other ions also were of diagnostic value.     

热裂解气相色谱-质谱联用法鉴别三种弹性纤维

采用热裂解气相色谱-质谱联用技术建立了聚氨酯纤维、二烯类和聚烯烃3种弹性纤维的鉴别方法。裂解温度为600℃时,可以最大限度同时显示聚氨酯纤维、二烯类和聚烯烃3种弹性纤维样品特征。聚氨酯纤维的特征性裂解产物是:不同聚合度(—O—CO—N—)n的中间体;特征离子碎片峰是荷质比(m/z)=71。二烯类纤维的特征性裂解产物是:异戊二烯及它的同分异构体和同系物、柠檬烯及它的同分异构体、β-律草烯及它的同分异构体、西柏烯及它的同分异构体等;特征离子碎片峰是m/z=68、79、93等。聚烯烃纤维的特征性裂解产物是:烯烃和烷烃;特征离子碎片峰是m/z=55、57等。