稳定同位素氘标记盐酸曲托喹酚的制备

以2-(3,4,5-三甲氧基苯基)乙酸为起始原料,经过脱甲基、酰胺化、甲基化、比希勒-纳皮拉尔斯基(Bischler-Napier-alski)环化反应、还原、脱保护基等关键反应步骤,得到稳定同位素氘标记的盐酸曲托喹酚.该合成方法原料廉价易得、简单成熟,目标产物氘同位素丰度较高.该产物经核磁共振氢谱(1 HNMR)和高...     

化学不稳定染发剂分子衍生物的液-质联用分析

染发剂成分化学性质不稳定,分析重现性差,根据《化妆品安全技术规范》(2015年版)溶液中染发剂禁、限用成分标准品的稳定性最多可维持48 h,难以用于大批量样品检验.为提高标准品的化学稳定性,选用结构简单的高反应活性亲核取代试剂(溴化苄)将苄基键合到7种苯胺类染发剂分子上(2-硝基对苯二胺、4-硝基邻苯二胺、对氨基苯酚、...     

除草剂的同位素残留分析进展

除草剂的使用对清除农田杂草、提高作物产量、解决粮食问题具有重要意义．但是除草剂的残留会对生态环境和人类健康造成影响。农药的同位素残留分析技术日益受到人们的重视。并取得了长足的发展。本文综述了利用同位素示踪技术对除草剂的残留分析进展。     

稳定同位素标记氨基甲酸乙酯-D_5的合成

以C2D5OD为原料,在催化剂作用下与氰酸钠一步反应得到标题化合物,以消耗的C2D5OD计算,收率55.3%。目标产物经气相色谱(GC)、质谱(MS)、核磁(NMR)等分析方法确证,化学纯度≥99.0%,同位素丰度≥99.0 atom%D,可以作为食品安全领域检测用同位素内标试剂。     

稳定同位素标记氨基酸细胞培养联合质谱绝对定量技术在5、7、55型腺病毒鉴定中的应用

利用稳定同位素标记肽段的质谱绝对定量(AQUA)技术,实现了对5、7和55型人腺病毒的准确鉴定。采用细胞培养条件下稳定同位素代谢标记(SILAC)技术培养细胞至大肠杆菌生长至对数生长期,1 mmol/L异丙基硫代-β-D-半乳糖苷(IPTG)低温诱导蛋白表达,提取并利用谷胱甘肽S转移酶(GST)纯化富集相应标记的腺病毒六邻体蛋白。通过胶消化分别消化三种不同标记策略(非标记、中度标记和重度标记)的纯化蛋白,消化肽段等量混合脱盐后经纳流液相色谱-串联质谱(Nano HPLC-MS/MS)进行定量蛋白分析。通过SILAC实现大肠杆菌的完整代谢标记,诱导表达腺病毒六邻体蛋白,通过AQUA技术实现对非标记、中度标记、重度标记六邻体蛋白标志性肽段鉴定。成功实现SILAC三种不同标记策略条件下大肠杆菌中5、7、55型人腺病毒六邻体蛋白的完整标记,为5、7、55型人腺病毒感染的快速分型检测提供了新的鉴定策略。     

稳定同位素标记恩诺沙星-D5的合成

该文提出简便的、丰度不稀释的方法合成恩诺沙星-D5,即以乙醇-D6为合成前体,与碘反应得到碘乙烷-D5,再进一步与环丙沙星烷基化生成目标产物。以消耗的乙醇-D6计算,恩诺沙星-D5总收率为69.9%。产品结构经质谱和核磁共振波谱等表征确定,D的同位素丰度为99.6%,色谱纯度为99.0%,可作为食品安全领域检测用同位素内标试剂。     

飞行时间质谱分析技术进展

质谱分析仪用来测定有机化学中分子结构和分子量,飞行时间质谱TOFMS（Time of Flight Mass Spectrometry）以其分析速度快,分析质量范围广而在生命科学,分析化学等领域得到了广泛的应用。综述了TOFMS的基本原理,技术和仪器的发展状况和发展方向,以及相关技术在生物分析方面的应用,并对今后的前景进行了展望．     

稳定同位素标记硼氘化钠的合成

通过对硼氢化钠的合成方法研究,确定了同位素标记硼氘化钠的制备方法:以硼砂、金属钠、氘气为原料,搅拌下将反应釜升温至450℃,反应0.5 h,得含硼氘化钠产品的粗砂,采用索氏提取法处理粗砂,得目标产物硼氘化钠产品,产品纯度99.2%,同位素丰度99.9 atom%D。     

电喷雾质谱质量重心法快速表征15N标记氨基酸同位素丰度

建立了15N标记同位素丰度的电喷雾质量重心分析方法,并成功的应用于5种15N标记氨基酸同位素丰度的表征。通过与15N标记氨基酸标准品标识的同位素丰度指标的比较,表明电喷雾质谱质量重心法对15N标记氨基酸同位素丰度的检测简单、准确、可靠,具有较好的分析检测实用性。本方法的快速制样和高通量检测的特性,使其比传统的气体同位素质谱法具有更高的检测效率和更低的检测成本,具有更为广阔的应用前景。     

稳定同位素标记的Y101及其代谢产物的合成

以氘代甲苯为原料,经高锰酸钾氧化反应生成氘代苯甲酸,再经缩合、烷基化、水解等反应,合成了N-(N-苯甲酰基-O-二甲氨基乙基-L-酪氨酰基)-L-苯丙氨醇及其代谢产物M-8、M-9的稳定同位素标记化合物。所得化合物均经核磁(NMR)、质谱(ESI-MS)进行结构确证。样品可作为生物内标,用于高效液相色谱/质谱联用法对目标化合物及其代谢产物在体内的定量分析,同时开展了该化合物的体内代谢研究。     

有机同位素稀释质谱法在食品安全分析中的应用

有机同位素稀释质谱法具有高精度、高准确度、样品无需严格分离等优点,已广泛应用于食品安全领域.简要介绍了有机同位素稀释质谱技术的机理和特点,综述了其在食品安全领域中的应用,并对其发展趋势进行了展望.     

Quantitative MALDI‐MS Binding Assays: An Alternative to Radiolabeling

Radiolabeling of ligands is still the gold standard in the study of high‐affinity receptor–ligand interactions. In an effort toward safer and simpler alternatives to the use of radioisotopes, we developed a quantitative and highly sensitive matrix‐assisted laser desorption ionization mass spectrometry (MALDI‐MS) method that relies on the use of chemically tagged ligands designed to be specifically detectable when present as traces in complex biological mixtures such as cellular lysates. This innovative technology allows easy, sensitive detection and accurate quantification of analytes at the sub‐nanomolar level. After statistical validation, we were able to perform pharmacological evaluations of G protein‐coupled receptor (V1A‐R)–ligand interactions. Both saturation and competitive binding assays were successfully processed.     

CORRECTION OF ANALYTICAL RESULTS FOR RECOVERY: DETERMINATION OF PAH s IN AMBIENT AIR,SOIL, AND DIESEL EMISSION CONTROL SAMPLES BY ISOTOPE DILUTION GAS CHROMATOGRAPHY-MASS SPECTROMETRY

Results from soil, diesel emission and ambient air control particulate matter samples on the determination of 30 PAHs were evaluated to establish whether the use of recovery data would result in an improvement of the quantitation accuracy over the uncorrected data. The performance of the recovery-corrected technique was initially evaluated using recovery results from PAH standard reference material samples spiked with analogue deuterated isotopes. The results showed an excellent correlation between recoveries of natives and corresponding surrogates for all matrices studied. The practical merit of the isotope dilution mass spectrometry technique was further assessed by spiking control samples with corresponding isotopic analogues and comparing the measured concentration of natives obtained with uncorrected and recovery-corrected techniques. The data revealed that the use of recovery correction leads to results closer to the real values, thus decreasing the negative bias due to losses that occur during the analytical process. The mean accuracy difference between uncorrected and corrected data is more pronounced as the sample matrix becomes more complex, such as soil (15 ± 12%) or diesel emission (8 ± 11%), and less for simpler ambient air matrix samples (3 ± 16%). Precision between the two techniques was comparable within each matrix and relatively close between the different matrices.     

Selective Analysis of Sulfur-Containing Species in a Heavy Crude Oil by Deuterium Labeling Reactions and Ultrahigh Resolution Mass Spectrometry

A heavy crude oil has been treated with deuterated alkylating reagents (CD₃I and C₂D₅I) and directly analyzed without any prior fractionation and chromatographic separation by high-field Orbitrap Fourier Transform Mass Spectrometry (FTMS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) using electrospray ionization (ESI). The reaction of a polycyclic aromatic sulfur heterocycles (PASHs) dibenzothiophene (DBT), in the presence of silver tetrafluoroborate (AgBF₄) with ethyl iodide (C₂H₅I) in anhydrous dichloroethane (DCE) was optimized as a sample reaction to study heavy crude oil mixtures, and the reaction yield was monitored and determined by proton nuclear magnetic resonance spectroscopy (¹H-NMR). The obtained conditions were then applied to a mixture of standard aromatic CH-, N-, O- and S-containing compounds and then a heavy crude oil, and only sulfur-containing compounds were selectively alkylated. The deuterium labeled alkylating reagents, iodomethane-d₃ (CD₃I) and iodoethane-d₅ (C₂D₅I), were employed to the alkylation of heavy crude oil to selectively differentiate the tagged sulfur species from the original crude oil.     

Position‐Specific Mass Shift Analysis: A Systematic Method for Investigating the EI‐MS Fragmentation Mechanism of epi‐Isozizaene

The EI‐MS fragmentation mechanism of the bacterial sesquiterpene epi‐isozizaene was investigated through enzymatic conversion of all 15 synthetic (¹³C₁)FPP isotopomers with the epi‐isozizaene synthase from Streptomyces albus and GC‐MS and GC‐QTOF analysis including MS‐MS. A systematic method, which we wish to call position‐specific mass shift analysis, for the identification of the full set of fragmentation reactions was developed.     

Harzianone Biosynthesis by the Biocontrol Fungus Trichoderma

Analysis of the volatile terpenes produced by seven fungal strains of the genus Trichoderma by use of a closed‐loop stripping apparatus (CLSA) revealed a common production of harzianone, a bioactive, structurally unique diterpenoid consisting of a fused tetracyclic 4,7,5,6‐membered ring system. The terpene cyclization mechanism was studied by feeding experiments using selectively ¹³C‐ and ²H‐labeled synthetic mevalonolactone isotopologues, followed by analysis of the incorporation patterns by ¹³C NMR spectroscopy and GC/MS. The structure of harzianone was further supported from a ¹³C,¹³C COSY experiment of the in‐vivo‐generated fully ¹³C‐labeled diterpene.