超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛查水产品中28种农药类环境激素

建立了超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛查和分析水产品中28种农药类环境激素的方法。样品经乙酸乙酯提取,Captiva ND Lipids小柱净化,用Acquity UPLC@BEN C18色谱柱(2.1mm×50 mm,1.7μm)分离,以甲醇和0.1%甲酸水溶液为流动相进行梯度洗脱。采用正、负离子切换同时测定了28种农药类环境激素,大大提高了检测通量。以全扫描模式下提取的保留时间和一级母离子精确质量数以及同位素丰度比,实现对水产品中多种农药类环境激素的快速筛查;以自动触发采集的二级碎片离子精确质量数进行确证。结果表明,目标化合物的线性关系良好,相关系数(r2)大于0.99;除乙草胺、腐霉利和杀螟硫磷外,其他化合物的检出限不大于10μg/kg,回收率为65.7%~98.9%,相对标准偏差为6.2%~11.3%。该方法简单、准确、快速、可靠,适用于水产品中多种农药类环境激素的高通量快速定性筛查和定量分析。     

谱图准确度在高分辨飞行时间质谱分析硝铵类有机炸药RDX中的应用

应用实时直接分析-高分辨飞行时间质谱(DART-HR-TOFMS)对硝胺类有机炸药黑索金(RDX)及其爆炸残留物进行精确质量质谱分析,借助MassWorks质谱解析软件对质谱数据进行了噪音过滤及峰形校正处理,获得了炸药准确的同位素分布模式,然后通过实际同位素分布模式的校正峰形与理论峰形匹配的谱图准确度对待选的分子式进行排序,实现了RDX的准确识别和鉴定。     

基于精确质量数筛选的亲水作用色谱-高分辨质谱法快速鉴别赤潮藻中的麻痹性贝毒素

采用亲水作用色谱-高分辨电喷雾质谱联用技术(HILIC-HR-ESI/MS)结合麻痹性贝毒素(PSP)精确质量数数据库,建立快速筛查、定性识别赤潮藻中各种常见PSP的方法。产毒藻细胞破碎后经0.1 mol/L乙酸溶液提取,通过HILIC-HR-ESI/MS正负离子模式全扫描分析,得到产毒藻粗提物中PSP化合物准分子离子及主要碎片离子精确质量数,结合PSP数据库筛查并辅以商品化软件数据分析,实现产毒藻所含PSP的快速定性识别。所建数据库包含25种常见PSP化合物精确分子质量及碎片离子信息,所发展的HILIC-HR-ESI/MS方法分离度高、灵敏度好,所考察的10种常见PSP化合物检测限在10～80 nmol/L范围内,能满足产毒藻实际样品的分析要求。3种产毒藻实际样品筛查、分析结果良好,说明本方法是赤潮藻中麻痹性贝毒素快速筛选、定性识别的有效方法。     

LC-TOF/MS无标准品定性筛查水果蔬菜中210种农药残留

建立了基于农药化合物列表(Database)无需标准品定性筛查水果蔬菜中210种农药的LC-TOF/MS方法。农药化合物列表包含农药的名称、保留时间、分子式和精确质量数。实验对检索中所需的精确质量数、保留时间窗口和离子化形式等进行了对比优化,用以提高筛查准确度,避免假阳性和假阴性结果的产生。采用标准溶液和基质添加样品,对方法的准确性、稳定性以及检测能力进行了探讨,结果表明,所有农药均能在10.0μg/kg(一律标准)下检出,化合物检索得分的相对标准偏差(RSD)均<20%。只需通过1次样品前处理,1次仪器测定,借助农药化合物列表实现无标准品对照下,对210种农药进行快速定性筛查,并且其性能指标均能够满足日常检测的需要。采用本方法对20个市售水果蔬菜样品进行了测定,发现了16种农药残留,包括常用农药,如多菌灵、烯酰吗啉、啶虫脒、甲霜灵、莠去津和噻菌灵等。     

气相色谱-飞行时间质谱快速鉴定和定量测定烟草中43种农药

建立了烟草中43种农药的气相色谱-飞行时间质谱(GC-TOF MS)分析方法。采用改进的Qu EChERS前处理方法,样品以丙酮-正己烷(1∶1)进行萃取,萃取液经N-丙基乙二胺(PSA)吸附剂分散固相萃取净化后,用GC-NCI-TOF MS进行检测。通过高分辨飞行时间质谱的精确质量数测定,建立了农药的特征离子数据库,结合目标物保留时间、碎片离子的丰度比、裂解规律、同位素离子峰簇等进行目标物定性鉴定。配制基质匹配标准曲线,以磷酸三苯酯(TPP)为内标进行定量测定。43种农药的线性相关系数(r2)均不小于0.993,相对标准偏差不大于9.6%,定量下限为1.3~5.0μg/kg;在3个水平下的加标回收率为76.4%~96.6%。该方法简单快速,准确性和灵敏度高,满足烟草中多农药残留的定性和定量检测要求。     

超高效液相色谱-四极杆-飞行时间质谱法快速筛查辣椒粉中27种农药残留

建立了超高效液相色谱-四极杆-飞行时间质谱（UPLC-Q-TOF/MS）快速筛查辣椒粉中27种农药残留的检测方法。样品采用乙腈提取,经Carb/NH₂固相萃取小柱净化,用乙腈-乙酸乙酯（3：1,v/v）洗脱,电喷雾正离子模式检测。在一级质谱模式下,以目标物的保留时间、精确质量数、同位素分布和同位素丰度比定性,以准分子离子峰的峰面积定量。在Targeted MS/MS模式下,通过相应碰撞能量下的离子碎片信息进一步确证。27种化合物在各自的线性范围内线性关系良好,相关系数均大于0.997。27种化合物的定量限为2.5~5.0 μg/kg,在3个添加水平下的回收率为72.3%~118.9%,相对标准偏差（RSD）为0.21%~12.7%（n=6）。该方法快速、灵敏、准确,适用于辣椒粉中多种农药残留的同时检测。     

高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速检测6种农产品中96种农药的残留量

利用高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛选辣椒、青花菜、脱水土豆、大豆、绿茶和大蒜中96种农药残留。样品经含0.1%醋酸的乙腈提取,分散固相萃取脱水、除色、净化后,以C18色谱柱为分析柱,甲醇和5 mmol/L醋酸铵水溶液作为流动相进行梯度洗脱分离。采用正、负离子切换同时测定96种农药残留,大大提高了检测通量。通过优化分辨率,在全扫描模式下提取目标化合物的精确质量数,有效地去除了基质干扰;采用自动触发采集二级质谱图进一步提高了定性的准确性。在1～200 μg/L范围内,96种农药的线性相关系数均大于0.99。通过实际样品的添加回收试验,回收率范围为58%～105%,相对标准偏差为8.8%～18.3%。该方法的检测低限可以达到5 μg/kg,可以作为蔬菜中多种农药残留高通量筛选和确认检测方法。     

高效液相色谱-离子阱飞行时间串联质谱法快速筛查保健食品中非法添加的磷酸二酯酶-5抑制剂及其类似物

采用离子阱飞行时间串联质谱(LC-MS-IT-TOF)技术对保健食品中非法添加的西地那非、他达那非和红地那非等28种磷酸二酯酶-5抑制剂(PDE-5)及其类似物进行快速筛查和确证。建立了此28种化合物的精确分子质量数和多级质谱碎片离子数据库。样品经甲醇超声提取,以C18色谱柱(150 mm×4.6 mm,3.5μm)分离,乙腈-0.1%乙酸为流动相梯度洗脱。结果显示,28种化合物的筛查检出限为0.2~7.0μg/L,定量下限为0.04~1.18 mg/kg(胶囊样品)和0.007~0.235 mg/L(口服液)。以定量下限浓度为加标水平的平均回收率为31.0%~114.0%,相对标准偏差(RSD)为2.5%~14.9%。利用精确质量数匹配和自建标准谱库检索,实现快速筛查;结合保留时间、同位素丰度和多级特征碎片离子对目标化合物进行确证。该方法具有简便、快速、准确、灵敏度高等优点,适用于保健食品中非法添加的磷酸二酯酶-5抑制剂(PDE-5)及其类似物的高通量筛查和定性鉴定。根据裂解规律的归纳总结,还可应用于其未知衍生物及结构类似物的分子式预测和结构推导。     

四极杆质谱分子式识别的稳定性

早期四极杆系统的精确质量测量,需要大规模的样品采集[1]或将系统调谐到更高的分辨率[2],而MassWorks软件(Cerno Bioscience)可以不需要频繁的校正,通过质量轴和峰形校正,实现精确质量测定,对离子进行元素组成识别,从而使分子式识别更加便利[3-4].由于在校正流程中包括了质量精度和谱图准确度,关于校正的稳定性,及其对实际检测的影响等问题也将应运而生.     

新型固相萃取-超高效液相色谱-串联四极杆静电场轨道阱高分辨质谱测定液态乳中舒巴坦

建立了新型固相萃取-超高效液相色谱-串联四极杆静电场轨道阱高分辨质谱测定液态乳中舒巴坦的方法。液态乳采用乙腈超声提取后,PRiME HLB固相萃取柱净化。以Thermo Hypersil Gold a Q(100 mm×2.1 mm,1.9μm)色谱柱进行分离,在电喷雾负离子模式下(ESI-),通过优化分辨率,在全扫描模式下提取目标化合物的精确质量数,采用自动触发采集二级质谱图进一步提高定性的准确性。在0.5~10μg/L范围内,线性关系良好,方法的定量限为0.5μg/kg,回收率为82.1%~95.5%,相对标准偏差为3.5%~6.2%。该方法操作简单,测定结果准确,可用于液态乳中舒巴坦残留的测定。     

Advanced Mass Calibration and Visualization for FT-ICR Mass Spectrometry Imaging

Mass spectrometry imaging by Fourier transform ion cyclotron resonance (FT-ICR) yields hundreds of unique peaks, many of which cannot be resolved by lower performance mass spectrometers. The high mass accuracy and high mass resolving power allow confident identification of small molecules and lipids directly from biological tissue sections. Here, calibration strategies for FT-ICR MS imaging were investigated. Sub-parts-per-million mass accuracy is demonstrated over an entire tissue section. Ion abundance fluctuations are corrected by addition of total and relative ion abundances for a root-mean-square error of 0.158?ppm on 16,764 peaks. A new approach for visualization of FT-ICR MS imaging data at high resolution is presented. The ??Mosaic Datacube?? provides a flexible means to visualize the entire mass range at a mass spectral bin width of 0.001?Da. The high resolution Mosaic Datacube resolves spectral features not visible at lower bin widths, while retaining the high mass accuracy from the calibration methods discussed.     

吖啶酮衍生物的质谱研究

报道了8个吖啶酮衍生物的MS-EI谱,并就MS—EI谱碎片的断裂方式进行了探讨,说明了取代基位置和取代基类型对吖啶酮衍生物稳定性的影响。     

三羰基铬苯乙烯甲酰衍生物的质谱研究

含有α、β不饱和酮和酰胺的三羰基铬芳基配合物的质谱未见有详细报道,本文报道标题化合物电子轰击(EI)质谱,并利用高分辨质谱数据和MS/MS联用技术探讨其裂解机理,观察到R基团的重排反应和在不同汽化温度下发生的双分子裂解反应和氢化反应等。     

4,6—二取代—3—酮—5硫酮—1,2,4—三嗪类化合物的质谱研究

1,2,4-三嗪类化合物具有抗癌、抗病毒、杀虫、抑制中枢神经系统等多种作用。前文用苯甲酰基硫代甲酰胺直接与氨基脲反应,制备了8种新的4,6-二取代-3-酮-5-硫酮-1,2,4-三嗪类化合物(a—h),本文测定了其电子轰击质谱、高分辨质谱及联动扫描质谱,以了解其质谱裂解途径。     

Boundaries of Mass Resolution in Native Mass Spectrometry

Over the last two decades, native mass spectrometry (MS) has emerged as a valuable tool to study intact proteins and noncovalent protein complexes. Studied experimental systems range from small-molecule (drug)–protein interactions, to nanomachineries such as the proteasome and ribosome, to even virus assembly. In native MS, ions attain high m/z values, requiring special mass analyzers for their detection. Depending on the particular mass analyzer used, instrumental mass resolution does often decrease at higher m/z but can still be above a couple of thousand at m/z 5000. However, the mass resolving power obtained on charge states of protein complexes in this m/z region is experimentally found to remain well below the inherent instrument resolution of the mass analyzers employed. Here, we inquire into reasons for this discrepancy and ask how native MS would benefit from higher instrumental mass resolution. To answer this question, we discuss advantages and shortcomings of mass analyzers used to study intact biomolecules and biomolecular complexes in their native state, and we review which other factors determine mass resolving power in native MS analyses. Recent examples from the literature are given to illustrate the current status and limitations.

电喷雾离子源正离子模式下环烯醚萜苷的质谱裂解行为

利用高分辨率四极杆-飞行时间串联质谱(Q-TOF MS/MS)对环烯醚萜苷同系组分7,8-环戊烯型和环戊烷型环烯醚萜苷在电喷雾正离子(ESI⁺)模式下的质谱裂解行为进行了研究. 在ESI⁺模式下, 环烯醚萜苷主要的质谱裂解途径是脱去母环上的功能基团, 如丢失H₂O, CO₂, CH₃OH, CH₃COOH和糖单元部分等, 由于它们均为葡萄糖苷, 所以共有碎片离子[Glc+Na]⁺(m/z 185.0). 环烯醚萜苷母核环上半缩醛结构的异构化造成二氢吡喃环的断裂, 但未发现与苷元部分在负离子(ESI^-)模式下相同的其它断裂. 环烯醚萜苷在ESI⁺模式下的断裂途径特征性不如其在ESI^-模式下的明显, 且灵敏度比后者低.     

Accurate mass filtering of ion chromatograms for metabolite identification using a unit mass resolution liquid chromatography/mass spectrometry system

Acceleration of liquid chromatography/mass spectrometric (LC/MS) analysis for metabolite identification critically relies on effective data processing since the rate of data acquisition is much faster than the rate of data mining. The rapid and accurate identification of metabolite peaks from complex LC/MS data is a key component to speeding up the process. Current approaches routinely use selected ion chromatograms that can suffer severely from matrix effects. This paper describes a new method to automatically extract and filter metabolite-related information from LC/MS data obtained at unit mass resolution in the presence of complex biological matrices. This approach is illustrated by LC/MS analysis of the metabolites of verapamil from a rat microsome incubation spiked with biological matrix (bile). MS data were acquired in profile mode on a unit mass resolution triple-quadrupole instrument, externally calibrated using a unique procedure that corrects for both mass axis and mass spectral peak shape to facilitate metabolite identification with high mass accuracy. Through the double-filtering effects of accurate mass and isotope profile, conventional extracted ion chromatograms corresponding to the parent drug (verapamil at m/z 455), demethylated verapamil (m/z 441), and dealkylated verapamil (m/z 291), that contained substantial false-positive peaks, were simplified into chromatograms that are substantially free from matrix interferences. These filtered chromatograms approach what would have been obtained by using a radioactivity detector to detect radio-labeled metabolites of interest.     

金黄色葡萄球菌及其甲氧苯青霉素耐药性的MALDI-TOF MS鉴定

用MALDI－TOS MS细菌指纹图谱鉴定细菌，建立区分金黄色葡萄球菌甲氧苯青霉素耐药株和敏感株的MALDI－TOF MS分析方法，检测了76株从临床标本中分离得到的金黄色葡萄球菌，用软件进行聚类分析，以nuc(耐热核酸酶）基因和mecA(耐药）基因聚合酶链反应（PCR）检测结果为参照，74％的菌株经MALDI－TOF MS给出了正确的鉴定结果；金黄色葡萄球菌甲氧苯青霉素耐药株和敏感株的质谱图有很大差别，各自有其特征峰；经过软件聚类分析，76株实验菌株划敏感群和耐药群；与PCR检测结果对照，有7株菌PCR检测mecA基因为阴性，而经MALDI－TOF MS鉴定为耐药株，表型鉴定表明其中有5株为敏感株；利用细菌指纹图谱和数据库检索对大多数菌株实现了正确鉴定；MALDI－TOF MS分辨率高，甚至可以区分株间的差异，实现了区分金黄色葡萄球菌甲氧苯青霉素耐药株和敏感株；结果表明MALDI－TOF MS提供了一个很有前景的鉴定细菌的快速方法。     

Mass spectrometry of doping preparations of a new generation: Peroxisome proliferator-activated receptor agonists

The mass spectral properties of the peroxisome proliferator-activated receptor agonists (PPARδ) have been studied by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) and high-performance liquid chromatography/high resolution mass spectrometry (HPLC/HRMS). Dissociation pathways of the investigated compounds under the conditions of collision activation have been proposed on the basis of the consolidated analysis of the data provided by these methods.     

Evaluation of a high-resolution time-of-flight mass spectrometer for the gas chromatographic determination of selected environmental contaminants

A benchtop high-resolution time-of-flight mass spectrometer (TOF MS) was evaluated for the determination of key organic microcontaminants. The major advantage of the TOF MS proved to be the high mass resolution of about 0.002 Da (10 ppm). Consequently, the detectability of polar pesticides, polynuclear aromatic hydrocarbons and polychlorinated biphenyls is excellent, and detection limits are in the order of 1–4 pg injected mass. Best mass spectral resolution was obtained for medium-scale peaks. It is a disadvantage that the calibration range is rather limited, viz. to about two orders of magnitude. The high mass spectral resolution was especially useful to improve the selectivity and sensitivity when analyzing target compounds in complex samples and to prevent false-positive identifications.