傅里叶变换红外光谱和傅里叶变换拉曼光谱法无损鉴别药材的真伪

利用傅里叶变换红外（FT-IR）和近红外傅里叶变换拉曼（NIR FT-aman）光谱法对大黄（西宁大黄）与伪品大黄（华北大黄、山大黄、水根大黄）进行了无损快速的鉴别。结果表明：尽管正品大黄与伪品大黄差别较小，有大部分的化学成分有很大的相同之处，但在红外、拉曼谱图中各自的特征峰较突出，根据谱峰的强度和位置可容易地将它们区别开来。红外和拉曼光谱法相互印证，相互补充，具有快速、准确、操作简单、重复性好、不需对样品进行分离提取，可直接鉴别等特点。     

皱叶香茶菜化学成分的研究

从采自西藏的皱叶香茶菜中分离鉴定了3对B-闭联对映贝壳杉烯型二萜化合物:二萜化合物皱叶香茶菜素(Ⅰ)和二氢皱叶香茶菜素(Ⅱ);isodocarpin(Ⅲ)和dihydroisodocarpin(Ⅳ)及Carpalasionin(Ⅴ)和dihydrocarpalasionin(Ⅵ)。(Ⅰ)、(Ⅲ)和(Ⅴ)分别与对应的二氢化合物(Ⅱ)、(Ⅳ)和(Ⅵ)以混合物的形式被分离和鉴定。化合物(Ⅱ)为新化合物,(Ⅰ)、(Ⅳ)和(Ⅵ)首次在自然界发现,(Ⅲ)和(Ⅴ)为已知化合物。     

A New Technique of Synthesizing 10—Hydroxy—5—methyl—5,10—dihydrophenophosphazine 10—Oxide

10-Hydroxy-5-methyl-5,10-dihydrophenophosphazine 10-oxide(1)was prepared by a new technique of treating 10-methoxy-5,10-dihydrophenophosphazine 10-oxide(2)with an equivalent of NaH in anhydrous DMF,and then at 120℃ for 3-4h,which not only avoided poisonous and expensive methyl iodide used in literature,but made the consumption of NaH greatly decrease as well.The possible reaction mechanism was also described.The chemical structure of 1 was confiremed by IR,NMR,and mass spectroscopy.     

Analysis of polynuclear aromatic hydrocarbons by glass capillary gas chromatography using simultaneous flame ionization and electron capture detection

The possibility of simultaneous application of an electron capture (ECD) and a flame ionization detector (FID) connected to a glass capillary column for analyzing polynuclear aromatic hydrocarbons (PNA) has been investigated. The ECD/FID ratio is determined for 46 PNA compounds. The ratios vary from 0.02 to 117 with relative standard deviations better than 20 percent determined from 10 replicate analyses. The results suggest that the method may be used for obtaining additional evidence in identifying PNA in environmental samples. Impurities and transformation products in the standard were identified by computerized glass capillary gas chromatography/mass spectrometry. Quinones and diones are responsible for the high EC-response determined in some trace components in the standard. An application of the method is shown for PNA from particulates in urban atmospheres.     

酿造酱油、配制酱油及酿造食醋、配制食醋的鉴别

乙酰丙酸是配制酱油的特有成分，在硫酸溶液中，乙酰丙酸可与香草醛反应而呈现蓝绿色。掺有尿素的酱油在与丁二酮肟、磷酸混合后，加热煮沸会呈现红色。用酱色、食盐等配制的劣质酱油可用测定氨基酸态氮和酱色含量的方法进行鉴别。酿造食醋和配制食醋的常用鉴别方法是碘液法和高锰酸钾法。     

Mass spectrometric methods for the analysis of chlorinated and nitrated isoflavonoids: a novel class of biological metabolites

Electrospray ionization combined with tandem mass spectrometry was applied to a study of some representative chlorinated and nitrated isoflavones-potential metabolites of isoflavones in inflammatory cells. Upon collision-induced dissociation of deprotonated [M - H](-) ions of these compounds, a number of structurally characteristic product ions were produced. The product ion analysis of 3'- and 8-chlorodaidzein in the tandom mass spectra led to ready differentiation of these isomers. 3-Nitro derivatives of both genistein and daidzein have product ions due to the losses of HNO(2) and two OH groups. Chlorinated derivatives of isoflavones were detected in cell-based experiments and their structures were proposed by comparing the tandem mass spectra of their product ions with those of standards. This work provides a suitable analytical basis to aid the characterization of chlorinated and nitrated metabolites in studies in vivo and in vitro.     

Individual determination of ortho and non-ortho substituted polychlorobiphenyls (PCBs) in sediments by high performance liquid chromatographic pre-separation and gas chromatography/ECD detection

Summary An analytical procedure for the individual determination of ortho and non-ortho PCB congeners in sediments, using high performance liquid chromatography (HPLC) preseparation and gas chromatography/ECD detection, is described. Gas chromatography/FTIR spectrometry (GC/FTIR) and gas chromatography/mass spectrometry (GC/MS) were employed for individual congener identification and determination. Sample extraction, clean-up of extract and selective elution procedures were optimized by using reference certified marine sediment samples. Recovery and precision were typically 83% and 16% respectively at 2 ng/g of total PCB content. The proposed procedure, tested by analyzing real sediment samples, showed a reproducibility better than 20% at 13 ng/g PCB level.     

Multivariate analysis of non-homogeneous peaks in liquid chromatography

Summary The effects of concentration, separation and spectral similarity as factors influencing the accuracy of iterative target testing factor analysis (ITT-FA) are investigated for three component systems by the application of analysis of variance (ANOVAR). ANOVAR is applied over a range of peak separations to map the changing effects of the three factors with increasing overlap. Two error responses were measured and analysed, (a) Relative cluster error (RCE) a measure of the error over all peaks in a cluster and (b) Relative peak error (RPE) the error of an individual peak. Multicomponent analysis (MCA) a method requiringa priori spectral information, is used as a referee method for ITT-FA.     

Identification of low molecular weight proteins isolated by 2-D liquid separations

Proteins with molecular mass (M(r)) <20 kDa are often poorly separated in 2-D sodium dodecyl sulfate polyacrylamide gel electrophoresis. In addition, low-M(r) proteins may not be readily identified using peptide mass fingerprinting (PMF) owing to the small number of peptides generated in tryptic digestion. In this work, we used a 2-D liquid separation method based on chromatofocusing and non-porous silica reversed-phase high-performance liquid chromatography to purify proteins for matrix-assisted laser desorption/ionization time-of-flight mass spectrometric (MALDI-TOFMS) analysis and protein identification. Several proteins were identified using the PMF method where the result was supported using an accurate M(r) value obtained from electrospray ionization TOFMS. However, many proteins were not identified owing to an insufficient number of peptides observed in the MALDI-TOF experiments. The small number of peptides detected in MALDI-TOFMS can result from internal fragmentation, the few arginines in its sequence and incomplete tryptic digestion. MALDI-QTOFMS/MS can be used to identify many of these proteins. The accurate experimental M(r) and pI confirm identification and aid in identifying post-translational modifications such as truncations and acetylations. In some cases, high-quality MS/MS data obtained from the MALDI-QTOF spectrometer overcome preferential cleavages and result in protein identification.