嘌呤衍生物在葫芦［6］脲单轮烷键合固定相上的色谱行为

在反相和正相色谱模式下,研究了几种嘌呤衍生物在葫芦［6］脲单轮烷键合硅胶固定相上的高效液相色谱行为,并在反相模式下与ODS固定相进行了比较,考察了流动相中甲醇含量、流动相pH值和离子强度对嘌呤化合物保留的影响。研究结果表明:在反相模式下,嘌呤化合物与葫芦［6］脲单轮烷键合相之间存在多种相互作用,除疏水作用外,分离过程中还存在与ODS不同的色谱分离机制。在正相条件下,多作用力的色谱分离机制同样存在。葫芦［6］脲单轮烷键合相与溶质之间存在疏水、氢键、π-π和偶极-偶极等多种作用力,协同作用提高了固定相对嘌呤化合物的分离选择性。     

几种非环单萜衍生物的制备及表征

分别以香叶醇、橙花醇及芳樟醇为原料,经SeO2和t-BuOOH氧化、NaBH4还原得到8-羟基香叶醇、8-羟基橙花醇及8-羟基芳樟醇;利用乙酰化反应和苯甲酰化反应分别制备了这三个二醇化合物的乙酰化和苯甲酰化衍生物;并利用气相色谱-电子电离质谱仪(GC-EIMS)和液相色谱-电喷雾质谱仪(LC-ESIMS)分析了合成产物的光谱性质.结果显示,以GC-EIMS表征合成产物时,除苯甲酰化衍生物呈现较弱的分子离子峰外,其他几个产物均无分子离子峰信号.     

苯二氮?类新精神活性物质氯硝唑仑的检验

建立了采用红外光谱(FTIR)、气相色谱-四级杆飞行时间质谱(GC/Q-TOF)和液相色谱-高分辨质谱(UPLC-LTQ-Orbitrap)鉴定检材中氯硝唑仑的方法,并通过核磁共振氢谱(~1HNMR)进行确认。样品经FTIR检测在1512cm~(-1)和1351cm~(-1)处存在芳香族硝基红外光谱特征吸收峰。用甲醇溶解后,上清液经GC/Q-TOF检测,保留时间为18.82 min组分的质谱碎片主要特征离子峰有353.0680(分子离子峰),324.0534(基峰),278.0605,249.0659,203.0730等。经UPLC-LTQ-Orbitrap检测,保留时间为12.72 min的质子化分子离子m/z为354.0739,碰撞诱导解离(CID)模式下二级质谱主要离子有326.0564,319.1063,308.0822。经SWGDRUG3.3谱库检索,资料对比和核磁共振氢谱共同确认目标物为苯二氮??类新精神活性物质氯硝唑仑。     

聚N-异丙基丙烯酰胺硅胶键合相的正相色谱性能研究

以3-巯丙基三甲氧基硅烷为偶联剂,将末端带有活性基团的聚N-异丙基丙烯酰胺(PNIPAM)键合到硅胶上,作为高效液相色谱固定相填料(Sil-PNIPAM)。以正己烷-异丙醇混合液为流动相,苯的衍生物为溶质对Sil-PNIPAM的正相色谱行为进行考察。结果表明该键合相在正相色谱模式下对带有供电子和/或者吸电子基团的化合物具有良好的色谱分离性能。研究表明,正相模式下该键合相的保留机理存在着氢键及π-π等相互作用机制。     

硝西泮、氯硝西泮甲基衍生物的气相色谱-质谱分析

对硝西泮和氯硝西泮的衍生化条件、色谱及质谱行为进行了研究,确立了猪肉中硝西泮、氯硝西泮残留的GC-MS检测方法.应用5因素4水平的正交试验,最终确定衍生化条件为反应温度60℃、反应时间30 min、丙酮用量0.5 mL、衍生化试剂20μL、催化剂无水碳酸钾20mg,在此条件下可生成较完全的甲基衍生物.衍生物具有较好的气相色谱和电子轰击质谱行为.硝西泮衍生物的分子离子峰为m/z 295,基峰离子为m/z 267,主要碎片离子分别为m/z 206、220、248、294;氯硝西泮衍生物的分子离子峰为m/z 329,基峰离子为m/z 328,主要碎片离子分别为m/z205、220、248、266、294、331,并对这些离子的产生进行了解析.这些离子均具有较强的相对丰度,可作为其微量检测的多离子选择定性和确证,而基峰离子可用于单离子选择定量.用乙腈提取药物,C18固相萃取柱净化,GC-MS分析.本方法采用外标法定量,两种药物的标准曲线线性回归系数均在0.99以上,线性范围20～500 μg/L,回收率80%左右,相对标准偏差6.9%～14.9%,检出限16.7 μg/kg.     

高效液相色谱法测定脱氢乙酸色谱条件综述

选取近年来食品中脱氢乙酸的液相色谱检测方法，总结色谱表现良好的液相条件，通过比较对影响因素进行分析。脱氢乙酸的色谱峰结果主要受到3方面因素的影响：一是流动相pH值及其中的弱酸弱碱调节剂，流动相pH值小于5或大于8的情况下脱氢乙酸色谱峰结果较好，可以通过加入有机弱酸弱碱如乙酸和氨水改善脱氢乙酸色谱峰；二是色谱柱的制造工艺，未封端的色谱柱裸露的硅羟基较多，可能与脱氢乙酸形成次级保留，封端的色谱柱更有利于脱氢乙酸检测；三是最大吸收波长，不同流动相条件下脱氢乙酸的最大吸收波长具有差异性，建议确定分析方法的流动相之后，选择对应的脱氢乙酸最大吸收波长，在一定程度上有利于改善灵敏度。     

液相色谱-大气压化学电离质谱法分析人参中的人参皂甙

研究了用反相高效液相色谱-大气压化学电离质谱(HPLC/APCI-MS)分析人参皂甙的方法。液相色谱采用乙腈-水流动相进行梯度洗脱,质谱采用正负离子同时扫描并结合二级质谱进行定性,用选择反应离子模式(SRM)测定检测限。实验发现虽然人参皂甙是热不稳定物质,但在大气压化学电离质谱的高温汽化过程中仍能检测到很强的负离子分子离子峰,而且随着汽化温度的升高,人参皂甙的负离子分子离子峰的强度增加。该方法对人参皂甙Rb1和Rg1的检测限分别为1.2×10-13 g和3.0×10-14 g,并检测出白参中包括丙二酰人参皂甙在内的29种人参皂甙。该法灵敏度高,重复性好,结果准确,能有效地对药材提取物中的多种人参皂甙进行检测和结构分析。     

氨基酸组成相同序列不同的小分子多肽的液相色谱-质谱联用分析

多肽组学是近年来兴起的一门新型学科,质谱已成为多肽组学研究的强有力手段．然而,用于检测具有相同氨基酸组成但序列不同的多肽时,只能给出等同的分子离子峰,在多肽结构解析上受到一定限制．因此,发展色谱分离．质谱检测联用技术是分析具有相同氨基酸组成但序列不同的多肽的有效途径．本文建立了一种氨基酸组成相同序列不同的小分子多肽的反相液相色谱分离-电喷雾离子化质谱检测新方法．该方法采用高效液相色谱-质谱联用技术,以两种三肽Gly．Ser．Phe和Gly．Phe．Ser为模式样品对象,考察了小分子多肽在不同流动相组成、流动相添加剂及pH等条件下的液相色谱行为,并讨论其保留机理．研究结果表明,在最优化的实验条件下,该方法稳定性好,重现性高,为多肽组学研究中的多肽解析提供科学的分析方法．     

应用质量源于设计的理念优化大鼠血浆中大黄蒽醌的分析方法

应用质量源于设计理念建立一种高效液相色谱-荧光检测法(HPLC-FLD)用于测定大鼠血浆中5种大黄蒽醌。用Plackett-Burman设计考察流动相中甲醇含量、pH值、流速、柱温和进样体积对色谱峰的分离度、理论塔板数、最末洗脱峰的保留时间和拖尾因子的影响,结果显示流动相中甲醇含量、流速和柱温对色谱系统的影响显著(p<0.05)。继而采用Box-Behnken设计结合响应面法考察上述三因素对分离度、保留时间和理论塔板数的影响。用Derringer渴求函数评价了响应值的综合作用。得出最优色谱条件为:以甲醇-0.1%(v/v)磷酸水溶液(81.4:18.6, v/v)为流动相等度洗脱,流速1.1 mL/min,柱温31℃,荧光检测激发波长为440 nm,发射波长为540 nm。建立的模型显示良好的预测性。结果表明:质量源于设计的理念可有效地应用于优化高效液相色谱分析方法。     

咪唑键合硅胶液相色谱固定相的正相色谱行为

该文将咪唑键合硅胶液相色谱固定相填充到毛细管中,在自制的微柱液相色谱系统下以碱性(胺类)和酸性(酚类)化合物为溶质对该固定相的正相色谱行为进行考察.结果表明该键合相在正相色谱模式下对碱性化合物具有良好的分离选择性,而酸性化合物在流动相中加入改性剂乙酸的条件下也实现了较好的分离.研究表明,正相模式下该键合相的保留机理存在着氢键、静电吸引及π-π等相互作用机制.     

Determination of three major triterpenoids in epicuticular wax of cabbage (Brassica oleracea L.) by high-performance liquid chromatography with UV and mass spectrometric detection

Lupeol, together with alpha- and beta-amyrins in smaller quantities, has been found for the first time in the epicuticular wax of white cabbage (Brassica oleracea L. convar. capitata (L.) Alef. var. alba DC) leaf surface extract. The three triterpenoids were identified by a new high-performance liquid chromatographic (HPLC) method with UV and mass spectrometric (MS) detection using atmospheric pressure chemical ionization (APCI). All three isomeric compounds gave a parent ion peak at m/z 409 [M+H-18](+) and the relative intensities of some characteristic fragment ion peaks in tandem mass spectrometric (MS-MS) spectra of this parent ion enabled differentiation between the isomers. An additional peak at m/z 439 [M+H](+), which could be oleanonic or ursonic aldehyde, was detected by HPLC-APCI-MS. Saponification of cabbage leaf surface extract with 20% NaOH in methanol at 65 degrees C for 2h had no influence on lupeol, or alpha- or beta-amyrins, but lead to the formation of three additional compounds, which were not identified.     

Identification of 1-hydroxypyrene glucuronide in tissue of marine polychaete Nereis diversicolor by liquid chromatography/ion trap multiple mass spectrometry

1-Hydroxypyrene glucuronide is identified as the single major aqueous metabolite of the tetracyclic aromatic hydrocarbon pyrene, in tissue from a deposit-feeding marine polychaete, Nereis diversicolor. Identification was performed using an ion trap mass spectrometer fitted with an atmospheric pressure chemical ionization (APCI) probe and connected to a high-performance liquid chromatography/diode array detector (HPLC/DAD) system. Besides 1-hydroxypyrene, the 339-nm UV trace of tissue samples from pyrene-exposed worms showed only one dominant peak that could be related to pyrene metabolism. Negative APCI-MS of this supposed 1- hydroxypyrene conjugate gave a characteristic signal at m/z 429 corresponding to the molecular ion of 1-hydroxypyrene glucuronide plus eluent adducts ([M - H + 2H(2)O](-)). Fragmentation pathways were studied by isolating the abundant ion at m/z 429 in the ion trap and performing multiple mass spectrometric experiments (MS(n)). The fragmentations observed were consistent with the proposed identification. Two low intensity LC peaks that could be related to pyrene metabolism by their DAD absorption spectra were also present in the 339-nm UV chromatogram of tissue samples. However, these peaks could not be identified by their mass spectra in negative ion mode due to ion suppression by very abundant co-eluting impurities. The present method shows that LC/MS(n) is a fast and useful analytical tool for identification of aqueous polycyclic aromatic hydrocarbon biotransformation products in samples from relatively small marine invertebrates with limited sample preparation.     

Determination of thiodiglycol, a mustard gas hydrolysis product by gas chromatography-mass spectrometry after tert-butyldimethylsilylation

A method for determining thiodiglycol (TDG), a mustard gas hydrolysis product in water, serum and urine samples using gas chromatography-mass spectrometry (GC-MS) after tert-butyldimethylsilylation (TBDMS) is described. Quantitation of TDG was performed by measuring the respective peak area on the extracted ion chromatogram of m/z 293, using an internal standard, the TDG homologue, thiodipropanol, peak area of which was measured as m/z 321. The presence of salts in the sample solution not only suppressed the loss of TDG by vaporization during the evaporation of water, but also facilitated the rate of production of di-silylated derivative, bis(tert-butyldimethylsilyoxylethyl)sulfide (TDG-(TBDMS)2). Under the pretreatment conditions used, in which 0.5 ml of water sample supplemented with 100 microM potassium chloride was evaporated to dryness under reduced pressure, followed by reaction with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide at 60 degrees C for 1 h, TDG-(TBDMS)2 was reproducibly detected with about a 55% recovery and a limit of detection (LOD, scan mode, S/N = 3) of 5.4 ng/ml. TDG was also determined by GC-MS from a 0.5 ml serum sample (after perchloric acid deproteinization) and from a 0.1 ml urine sample, after TBDMS derivatization. The LOD was determined to be 7.0 and 110 ng/ml for serum and urine, respectively.     

应用搅拌棒吸附萃取-热脱附-气相色谱-质谱分析烟用香料的化学成分

应用搅拌棒吸附萃取法(SBSE)提取烟用香料的化学成分,并利用热脱附(TD)和色谱-质谱联用(GC-MS)进行分析。对影响萃取效果的因素(萃取时间和氯化钠的加入量)进行了考察,并采用正交试验法对影响热脱附的3个主要因素(脱附温度、脱附时间和冷阱温度)进行了优化,得到了较优的实验条件。对方法的重现性进行了考察,同一样品6次测定所得30个组分的峰面积的相对标准偏差（RSD）平均值小于10%,说明所建立方法的重现性较好。在样品中鉴别出酯类、酮类和醛类等30种不同化学组分,这些物质反映了该香料的香气特点。实验证明SBSE和TD适用于烟用香料的快速分析测定。     

Analysis of 3,5-dichloroaniline as a biomarker of vinclozolin and iprodione in human urine using liquid chromatography/triple quadrupole mass spectrometry

The fungicides vinclozolin and iprodione are widely used in agriculture. These pesticides are dicarboximide fungicides containing the common moiety 3,5-dichloroaniline (3,5-DCA). It has been suggested that low-level exposures to such compounds may be associated with adverse health effects such as endocrine disruption. In this study a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) was developed for the analysis of 3,5-DCA as a biomarker of exposure to these fungicides in human urine. The urine samples were treated by basic hydrolysis to degrade the fungicides, their metabolites and conjugates to 3,5-DCA. The 3,5-DCA was then extracted using toluene and derivatized using pentafluoropropionic anhydride (PFPA). Analysis of the derivative was carried out using selected reaction monitoring (SRM) in the negative ion mode. Quantification of the derivative was performed using [(13)C(6)]-labeled 3,4-DCA as an internal standard with good precision and linearity in the range 0.1-200 ng/mL urine. The limit of detection was determined to be 0.1 ng/mL. The metabolites in urine were found to be stable during storage at -20 degrees C. To validate 3,5-DCA as a biomarker the method was applied in a human experimental exposure to iprodione and vinclozolin. Two healthy volunteers received 200 microg single oral doses of each pesticide followed by urine sampling during 72-120 h post-exposure. Between 78-107% of the dose was recovered as 3,5-DCA in the urine after exposure.     

银杏叶提取物中染料木素的分离纯化及结构鉴定

对银杏叶提取物进行酸水解,然后利用正相硅胶柱色谱及重结晶法从银杏叶水解物中分离出染料木素,经紫外光谱（UV）、质谱（MSn）、核磁共振（1H NMR、13C NMR）等波谱学方法鉴定证实了其结构。高效液相色谱分析表明,所提纯的染料木素纯度达到了98%以上。     

大气压化学电离-高分辨质谱直接分析食用油中的甘油三酯

建立了食用油中甘油三酯的大气压化学电离-质谱直接分析检测方法.在考察实验条件影响的基础上,选择乙腈作为溶剂,正离子检测模式,进样流速为800 μL/h,喷雾器温度250℃,电晕针电流为5000 nA.用本方法对10种食用油进行分析,结果表明,植物油与动物油之间差异较大.经主成分分析,选择m/z 857.76与m/z 881.76峰强度比作为指标,重复性RSD＜5％,可直接识别出玉米油中掺杂5％的猪油.用碰撞诱导解离(CID)实验初步鉴别了食用油的3个特征峰.利用本方法对泔水油样品和煎炸油样品进行分析,结果泔水油样品中含有植物油和动物油,而煎炸油样品也与商品食用油存在差异.本方法可用于食用油样品的快速筛查.     

反式白藜芦醇热稳定性与光致异构化的高效液相色谱和液相色谱-电喷雾离子化质谱研究

应用高效液相色谱(HPLC)及液相色谱-电喷雾离子化质谱(LC-ESI-MS)方法对反式白藜芦醇的长期热稳定性及光致顺反异构化反应进行了研究。色谱条件为:采用Hypersil-ODS色谱柱分离,流动相为甲醇-0.05%三氟乙酸水溶液(体积比为60∶40)(用于HPLC分析)及甲醇-5 mmol/L甲酸铵水溶液(含0.1%甲酸)（体积比为60∶40)(用于LC-ESI-MS分析),检测波长300 nm,进样量20　μL(HPLC)或10 μL(LC-ESI-MS);质谱检测中设定为负离子模式。在4~40     

Temperature effect on peak width and column efficiency in subcritical water chromatography

Subcritical water has been recently employed as the mobile phase to eliminate the use of organic solvents in reversed-phase liquid chromatography. Although the influence of temperature on retention in subcritical water chromatography has been reported, the temperature effect on peak width and column efficiency has not yet been quantitatively studied. In this work, several polar and chlorinated compounds are separated using pure subcritical water on Zorbax RX-C8, PRP-1 (polystyrene-divinylbenzene), Hypersil ODS, and ZirChrom-polybutadiene columns. Isothermal separations are performed at temperatures ranging from 60 degrees C to 160 degrees C. The retention time and peak width of analytes are reduced with increasing temperature. However, the column efficiency is either improved or almost unchanged with the increasing temperature in the low-temperature range (lower than the 100 degrees C to 120 degrees C range), but it is decreased when temperature is further raised in the high-temperature range (higher than the 100 degrees C to 120 degrees C range). Therefore, a maximum in column efficiency is obtained at temperatures within the 100 degrees C to 120 degrees C range in most cases.     

The distinction of underivatized monosaccharides using electrospray ionization ion trap mass spectrometry

A convenient method for distinguishing underivatized isomeric monosaccharides has been established using electrospray ionization ion trap mass spectrometry (ESI-ITMS). Mass spectra of hexoses (glucose, galactose, and mannose), N-acetylhexosamines (N-acetylglucosamine, N-acetylgalactosamine, and N-acetylmannosamine) and hexosamines (glucosamine, galactosamine, and mannosamine) dissolved in solvent containing 1 mM ammonium acetate were obtained in the positive ion mode. Glucose was distinguished from galactose and mannose in the MS(2) spectrum of the [M+NH(4)](+) ion at m/z 198. The MS(3) spectra generated from [M+NH(4)-H(2)O-NH(3)](+) at m/z 163 showed that galactose and mannose could be distinguished by the ratio of peak intensities at m/z 145 and 127, while the three N-acetylhexosamine and hexosamine stereochemical isomers could be identified by the relative abundance ratios of product ions observed in MS(3) spectra. The investigation of MS and MS(2) spectra from complexes of these monosaccharides with Na(+) and Pb(2+) failed to distinguish these monosaccharide isomers. Therefore, multiple stage mass analysis by ESI-ITMS using either [M+NH(4)](+) or [M+H](+) was useful to distinguish between the isomers of monosaccharides.