UPLC-Q-TOF-MSE技术结合UNIFI筛查平台快速分析刺梨籽中化学成分

采用超高效液相色谱-四极杆飞行时间质谱（UPLC-Q-TOF-MS^E）联用技术结合UNIFI筛查平台对刺梨籽提取物的化学成分进行分析鉴定。利用UPLC-Q-TOF-MS^E技术采集刺梨籽甲醇提取物乙酸乙酯部位的质谱数据，并通过UNIFI筛查平台结合各化合物的相对保留时间、精确分子质量、分子式、特征性碎片离子以及相关文献数据，共鉴定出刺梨籽提取物中的55种化合物，包括19种黄酮和36种三萜类化合物。该方法可为进一步研究刺梨籽的药效物质基础及其作用机制提供数据支持。     

舒它西林的电喷雾-四极杆-飞行时间串联质谱裂解规律研究

为阐明药物舒它西林（氨苄西林/舒巴坦）的质谱裂解规律,采用电喷雾-四极杆-飞行时间串联质谱(ESI-Q-TOF-MS/MS)法在正离子模式下,对其离子碎片结构进行分析。通过质谱的高分辨能力及同位素氘代信息推断出舒它西林[M+H]⁺碎片离子断裂途径主要为氨苄西林部分的β-内酰胺环断裂,[M+Na]⁺裂解可观察到较多碎片离子峰,包括氨苄西林部分β-内酰胺环断裂、双酯连接处断裂和舒巴坦部分四元环断裂,此外有脱去CO₂、SO₂、CO等中性分子的峰出现。两种分析模式可为舒它西林的结构解析、体内代谢物质或环境中降解产物的研究提供快速鉴别理论依据。     

UPLC-Q-TOF-MSE技术结合UNIFI筛查平台快速分析补骨脂化学成分

采用超高效液相色谱-四极杆飞行时间质谱（UPLC-Q-TOF-MS^E）联用技术结合UNIFI筛查平台对补骨脂提取物的化学成分进行分析鉴定。利用UPLC-Q-TOF-MS^E技术采集补骨脂甲醇提取物的质谱数据,并通过UNIFI筛查平台结合各化合物的相对保留时间、精确分子质量、分子式、特征碎片与文献数据及标准品信息,共鉴定出补骨脂提取物中的44种化合物,包括28种黄酮类、10种香豆素类、2种单萜类和4种其他成分化合物,其中12种成分为首次在补骨脂中发现。该方法可为进一步研究补骨脂的质量控制、药效物质基础、药理作用等奠定基础。     

巴戟天中环烯醚萜苷和蒽醌在电喷雾离子源负离子模式下的质谱裂解行为

利用电喷雾-四极杆-飞行时间串联质谱（ESI-Q-TOF MS/MS）技术,在负离子模式下,探讨巴戟天中4种环烯醚萜苷和2种蒽醌成分的质谱裂解途径。通过［M-H］^-获得化合物的相对分子质量信息,进一步对［M-H］^-进行碰撞诱导解离,获得相应化合物的裂解途径。结果表明,环烯醚萜苷主要的裂解途径是首先脱去母环上的功能基团,如中性丢失H₂O、CO₂、CH₃COOH和糖单元等部分;其次是二氢吡喃环和糖环的断裂,m/z 113、101为环烯醚萜苷母环断裂的特征碎片离子。蒽醌类化合物的裂解行为是连续失去CO,也可以失去CO₂。这些质谱裂解行为的研究有助于环烯醚萜苷和蒽醌类化合物的结构解析,也可为其他同类化合物的鉴定提供依据。     

计算化合物分子式的五种方法

计算化合物分子式的五种方法包括高分辨质谱法 ( HRMS) ,高分辨质谱数据法 ( HRMS data) ,元素分析法 ( EA) ,1 3 C-核磁共振 ( COM,DEPT)数据法 ( 1 3 C-NMR( COM,DEPT) data)和三相似法。第一种方法 :根据 HRMS测得的分子量精确值 M和环加双键数 ( r+db) ,推断出化合物的分子式。第二种方法 :计算分子式的方法与第一种方法相类似 ,只不过是首先应按照测得的精确分子量的尾数 ,估算出分子式的总含氢原子数 ,然后再确定分子式。第三种方法 :按照 HRMS测量的 M、( r+db)和 EA测量的化合物的组成元素百分比含量 ,计算分子式。第四种方法 :根据 1 3 C-NMR测量的化合物分子各组成功能团的数目来确认分子式。第五种方法 :通过被测化合物的特征离子质谱与共同的分子式 CH3 ( CH2 ) n COR进行比较后 ,推断出分子式 ,例如柱晶白霉素、麦地霉素和生枝霉素具有共同的分子式 C3 5H56NO1 3 RR1 R2 ,其差别仅是它们的 R、R1 和 R2 不同。     

MassworksTM结合NIST11谱库在羊油香气成分准确定性分析中的应用

应用Massworks^TM质谱解析软件结合NIST11谱库,定性分析羊油的香气成分。在Massworks^TM质谱解析软件中,以全氟三丁胺质谱图为标准建立质谱校正函数,对热脱附-气相色谱-质谱联用法（TD-GC/MS）采集的羊油香气原始扫描谱图进行质量轴和峰形校正,通过低分辨质谱获得各化合物的精确质量数,并利用同位素峰形校正技术（CLIPs Search）进行检索,获取未知目标化合物的分子式,同时与NIST11谱库的检索结果比对。结果表明,通过Massworks^TM与NIST11谱库结合实现了快速、准确定性分析羊油香气成分,最终确定42种香气成分。利用Masswork^TM软件的参数优化,解决了NIST11谱库中检索匹配度低、存在共流出化合物以及目标化合物无分子离子峰等问题,获取了化合物离子碎片信息并进行了解析。该定性方法可为未知天然产物香气成分的分析提供方法参考。     

伏毛铁棒锤根中总生物碱的串联质谱分析

采用电喷雾串联质谱（ESI-MSⁿ）和高分辨电喷雾质谱（HR-ESI-MS）对伏毛铁棒锤根中总生物碱进行分析。由一级质谱图获得各生物碱成分的准分子离子峰，通过高分辨质谱测出其相应的分子式，再经串联质谱获得一些分子结构信息，伏毛铁棒锤根中的5个主要生物碱成分为12-表-欧乌头碱、3-脱氧乌头碱、乌头碱、3-脱氧乌头碱-8-亚油酸酯和乌头碱-8-亚油酸酯。     

天然同位素信息在多级质谱裂解规律解析中的应用——以磺胺类化合物为例

为了更好的对多级质谱裂解信息进行解析,本研究在多级质谱中应用同位素峰信息进行分子式确证。使用二级质谱中同位素峰丰度比例和峰形信息,对化合物的质谱裂解碎片分子组成进行预测和推断。通过改变LTQ Orbitrap XL仪器的离子阱参数,将isolation width设为6 u,使目标母离子的最轻同位素峰和两个较重同位素峰共同裂解,报道了在二级质谱中获得目标化合物的同位素信息,并使用这些信息对化合物裂解碎片进行推测。以磺胺甲基嘧啶为例,通过同位素信息提供的丰度比和峰形信息,对主要裂解碎片离子进行解析,大多数结果与文献报道的裂解途径一致,但对于磺胺甲基嘧啶二级质谱中m/z 65的碎片离子,与已发表的文献报道不同,通过高分辨质谱和同位素丰度比的佐证,重新对其进行了解析,证明这是一个不含硫元素的子离子。结果表明,该方法能够有效减少分子式推测过程中产生的错误备选结果,可以为多级质谱的解析提供更准确的依据。     

哌嗪类新精神活性物质的质谱特征研究

为阐明哌嗪类化合物的质谱裂解规律,在碰撞诱导解离（CID）模式下,采用电喷雾-串联质谱法（EI-MS/MS）分析苄基哌嗪（BZP）、1,4-二苄基哌嗪（DBZP）、1-（3-氯苯基）哌嗪（mCPP）、1-（3-三氟甲基苯基）哌嗪（TFMPP）4种哌嗪类新精神活性物质,并进行质谱解析,推测各化合物可能的裂解途径。结果表明,在CID模式下,哌嗪环和苯环之间的C—N键以及哌嗪环内的C—N键均易发生断裂形成特征离子。该类化合物的裂解规律可为哌嗪类物质的结构鉴定提供理论基础。     

国产高分辨飞行时间质谱仪在药物分子结构鉴定中的应用

为了考察自主研发的API-TOF MS 10000电喷雾高分辨飞行时间质谱仪（ESI-TOF MS）对离子准确质量数测定的准确性及其在新药研发中的应用前景,采用该仪器对新药研发中涉及的291个天然产物及合成物进行质谱分析。以三氟乙酸钠为内标物进行仪器质量轴校准,将测试得到的目标离子准确质量数与理论准确质量数对比,计算两者的相对误差。结果表明：248个样品的分子质量测试结果与预期一致;对其中202个样品进行高分辨质谱测试,所得实验值与理论准确质量数之间的相对误差均小于5×10^-6;与预期不一致的实验结果提示样品的结构解析有误,并得到了其他波谱数据的验证。采用API-TOF MS 10000和美国AB Sciex公司的QSIAR Elite型Q/TOF MS对抗癌药物马来酸阿法替尼和降糖药利格列汀杂质进行质谱分析。结果表明,自主研发的API-TOF MS 10000与国际同类仪器对药物分子准确质量数的测试结果无明显差异,可以提供化合物准确的分子质量和分子式信息,是新药研发中药物分子结构解析的有力工具。     

基于分子式数据库策略的FM-searcher软件在危害物非目标筛查分子式预测中的应用

利用高分辨质谱数据进行非目标筛查时，为提高分子式预测的前位命中率，为化合物的进一步筛查提供可靠的参考信息，本研究开发了基于分子式数据库策略的分子式计算器FM-searcher。该软件基于“存在即合理，大量存在即稳定”的核心思想，根据分子式在已有化合物数据库中出现的频率对分子式进行计算和排序，并依据排序对获得分子式的合理性进行判断，以提高分子式计算的合理性和前位命中率。以测定及搜集文献所得兽残、生物毒素等多类危害物共计219个精确分子质量作为测试数据，将该计算器计算的分子式前位命中率与普通算法（Xcalibur内嵌计算器）的计算结果进行比较。结果表明，FM-searcher在无任何元素限制时，仍可获得较高的前位命中率，前5、前3及首位命中率分别为91.8%、82.6%和50.7%；而普通算法在模糊限制元素时，其命中率分别为21.0%、15.1%、6.4%。在分小类精确限制元素组成时，得到的结果分别为82.2%、69.9%、48.9%。对实际样品基质中测定得到精确质量数的分子式进行计算，FM-searcher能够获得比普通计算器更高的正确分子式前位命中排位。该方法与普通算法相比，能够在更宽泛的限制条件下大幅提高分子式预测的前位命中率，简化分子式计算过程，减少数据处理量，且操作简便、实用性较强。     

人参中人参皂甙成分的高分辨多级质谱分析

Ginsenosides is a key class of compound in Ginseng plant and was proved for many pharmacological efficacies such as anti-aging, memory enhancement and etc. Recent study indicates Ginsenoside Rh2 and Rg3 revealed antitumor activity. It is reported 39 Ginsenosides were separated and identified for the elemental composition and structure. An LC/MS approach to analyze new active compound is developed by using high resolution and tandem mass spectrometer which is considered to facilitate the discovery and identification of new chemical entity. In this work, the class compound of ginsenosides in Panax Ginseng extract were determined for accurate mass of both parent and product ions with multi stage fragmentation by using hybrid mass spectrometer LTQ-Orbitrap. Among total 37 compounds, 13 of them were confirmed based on accurate mass of parent ion, and other 24 were determined for mass at accuracy less then 1×10^－6. All compounds received single formula of elemental composition. An illustrated unknown ginsenoside was elucidated for structure unit aglycone and number of glycosyl.     

High-ThroughputScreeningofIllegalDrugsinComplexMatrixbyLiquidChromatographyTandemQuadrupole-TimeofFlightMassSpectrometry

Tandem quadrupole-time of flight(QTOF) mass spectrometry can provide the high accurate mass (＜2×10^－6) of parent and product ions for small and large molecules with excellent sensitivity and high mass resolution. Especially for the trace analysis in complex matrix(e.g. food, serum, fluid, environmental matrix), HPLC-QTOF plays an important role in identification and determination. In this study, a 250-illigal drug database based on accuracy mass was established, and a process for rapid screening and confirming of non-target illegal drugs was presented using urine and oral fluid preparation. The real samples were rapidly screened for illegal drugs using the molecular feature Extraction(MFE) algorithm of the Agilent Mass Hunter software, the established drug database, and accurate mass spectra using liquid-chromatography(LC), electrospray(ESI), quadrupole-time-of-flight mass spectrometry(Q-TOF LC/MS). The TOF data was processed by MFE, based on which the ions from noise and background were greatly removed. Using the MFE algorithm, a compound list containing interesting ions were contracted and the related chemical formula were calculated based on accuracy mass and isotope ratio calculation. Accurate masses of the ions detected and identified by MFE were compared to the exact masses of compounds in the database. Positive compounds were then further confirmed using the MS/MS(Q-TOF LC/MS) mode. Finally, the product ions from MS/MS mode are used for the determination of illegal drugs in the positive samples, and the methodology(linearity, repeatability and sensitivity) were investigated.     

Time of flight mass spectrometry applied to the liquid chromatographic analysis of pesticides in water and food

Liquid chromatography coupled to mass spectrometry (LC-MS) is an excellent technique to determine trace levels of polar and thermolabile pesticides and their degradation products in complex matrices. LC-MS can be equipped with several mass analyzers, each of which provides unique features capable to identify, quantify, and resolve ambiguities by selecting appropriate ionization and acquisition parameters. We discuss in this review the use of LC coupled to (quadrupole) time-of-flight mass spectrometry (LC-(Q)ToF-MS) to determine the presence of target and non-target pesticides in water and food. This technique is characterized by operating at a resolving power of 10,000 or more. Therefore, it gives accurate masses for both parent and fragment ions and enables the measurement of the elemental formula of a compound achieving compound identification. In addition, the combination of quadrupole-ToF permits tandem mass spectrometry, provides more structural information, and enhances selectivity. The purpose of this article is to provide an overview on the state of art and applicability of liquid chromatography time-of-flight mass spectrometry (LC-ToF-MS), and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) for the analysis of pesticides in environmental matrices and food. The performance of such techniques is depicted in terms of accurate mass measurement, fragmentation, and selectivity. The final section is devoted to describing the applicability of LC-(Q)ToF-MS to routine analysis of pesticides in food matrices, indicating those operational conditions and criteria used to screen, quantify, and identify target and "suspected" pesticides and their degradation products in water, fruits, and vegetables. The potential and future trends as well as limitations of LC-(Q)ToF-MS for pesticide monitoring are highlighted.     

集高分辨定性鉴定与高灵敏度定量分析于一身的气相/质谱系统领路者—安捷伦7200气相/四极杆飞行时间质谱联用仪

本文主要介绍了全新的安捷伦7200气相/四极杆飞行时间质谱。安捷伦7200 GC/Q-TOF（气相色谱/四极杆飞行时间质谱）将分离功能强大的7890A GC和高分辨率的TOF质谱仪以及高灵敏度的四极杆相结合,全新定义了GC/MS技术。凭借创新的离子源设计,耐高温的石英质量过滤器,高效的碰撞池,32G/s的数据采集速率和高温稳定的ADC TOF电子元件,安捷伦7200 Q-TOF为结构确认分析带来最高特异性的检测和最准确的分子式解析,使您信心十足地迎接最艰巨的分析挑战。     

科里奥利颗粒料质量流量计流量公式理论分析

本文通过对科里奥利固体颗粒料质量流量计的结构分析，认为该流量计无法获取实时的质量流量，并对公开的瞬时流量计算公式进行了理论分析，说明其理论上的缺陷，给出了详细的推证过程和更为精确的理论计算方法和措施。     

Accurate mass measurement for the determination of elemental formula--a tutorial

The application of accurate mass measurement for the determination of elemental formula has its origin in the 1950s and for many years was only carried out using magnetic sector mass spectrometers. The availability of such measurements was limited due to the cost and complexity of the instrumentation and the need for considerable expertise to acquire and interpret the spectra. In recent years the incredible pace of instrumental development has changed this, particularly with the renaissance of time of flight mass spectrometry. This has resulted in instrumentation capable of making accurate mass measurements in a robust fashion becoming available to most practitioners of (mass spectrometry) MS, without some of the earlier technical challenges and at lower cost. In this review the variety of accurate mass measurement instrumentation and techniques and their relative capabilities are discussed, along with a range of applications requiring the determination of elemental formula.     

高精度影像测量系统中图像的超分辨率重建

为了提高影像测量系统的测量精度,研究了基于微位移错位的多幅图像超分辨重建技术.考虑制作成本和制作难度,提出了一种不苛求精确微位移的超分辨率重建技术.首先,获取随机微位移图像序列;然后,利用被测对象中易于实现高精度提取的特征点或采用模板衬底中的特征点计算出图像序列间的准确位移关系;最后,根据本文提出的数学模型重建出高分辨...