A new analytical approach for the comprehensive characterization of polar xenobiotic organic compounds downgradient of old municipal solid waste (MSW) landfills

Groundwater samples collected downgradient from a former municipal solid waste landfill near Berlin, Germany, were analyzed by GC-MS, HPLC-MS, and HPLC-NMR hyphenated techniques to comprehensively characterize the xenobiotic organic compounds (XOCs). The focus thereby was on the detection and identification of the polar XOCs which were analyzed in the extract obtained after separation of the unpolar components by pre-extraction. HPLC-NMR and HPLC-MS runs were used to identify polar XOCs on-line or to obtain preliminary structure information on the other XOCs. These compounds were then isolated by HPLC fractionation and their structures elucidated by off-line NMR and MS investigations. A variety of polar XOCs, products of the dye industry, degradation products of polyethylene glycol, and some heterocyclic compounds could be identified. Furthermore, a semi-quantitative estimation of the identified polar compounds is given.     

气相色谱／质谱法鉴定甲基异丁基酮产品中的杂质组分

采用ＧＣ／ＭＳ联用技术分离出甲基异丁基酮产品中６个杂质峰。将标准图谱库，质量色谱图等手段结合起来鉴定出７种杂质，并用标样，双柱对部分ＧＣ／ＭＳ的结果进行了证实，为产品质量控制提供依据。     

Analysis of highly polar compounds in groundwater samples from ammunition waste sites. Part I-Characterization of the pollutant spectrum

Five groundwater samples from the former ammunition production site at Elsnig, Germany, were analyzed for highly polar components by LC-NMR and LC-MS. A variety of unknown pollutants could be identified. Possibilities and limitations of the combined use of LC-NMR and LC-MS techniques for on-line identification are discussed. Further unknown components were identified through isolation by HPLC cuts and off-line NMR and MS investigations. Most of the polar compounds in the investigated samples could also be quantified.     

Identification of highly polar nitroaromatic compounds in leachate and ground water samples from a TNT-contaminated waste site by LC-MS,LC-NMR,and off-line NMR and MS investigations

Leachate and ground water samples from a trinitrotoluene-contaminated waste disposal site near a former ammunitions plant in Stadtallendorf, Germany, were analyzed by liquid chromatography (LC)-mass spectrometry (MS) and LC-NMR hyphenated techniques to comprehensively characterize the range of highly polar nitroaromatic compounds. Wherever unknown components could not be identified by comparison with a multistandard, the spectroscopic data obtained on-line were used to make initial structure proposals, which were later confirmed by comparison with authentic reference materials. In those cases where reference materials were not commercially available, unknown compounds were isolated by HPLC cuts and their structures were elucidated by off-line NMR and MS investigations. A variety of previously unknown compounds, including nitrophenols, nitrobenzyl alcohols, methylnitrobenzoic acids, and hydroxynitrobenzoic acids, could be identified. The NMR and MS data are presented here. The main polar compounds were additionally quantified.     

Metabonomics investigation of human urine after ingestion of green tea with gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and (1)H NMR spectroscopy

A method using gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and (1)H NMR with pattern recognition tools such as principle components analysis (PCA) was used to study the human urinary metabolic profiles after the intake of green tea. From the normalized peak areas obtained from GC/MS and LC/MS and peak heights from (1)H NMR, statistical analyses were used in the identification of potential biomarkers. Metabolic profiling by GC/MS provided a different set of quantitative signatures of metabolites that can be used to characterize the molecular changes in human urine samples. A comparison of normalized metabonomics data for selected metabolites in human urine samples in the presence of potential overlapping peaks after tea ingestion from LC/MS and (1)H NMR showed the reliability of the current approach and method of normalization. The close agreements of LC/MS with (1)H NMR data showed that the effects of ion suppression in LC/MS for early eluting metabolites were not significant. Concurrently, the specificity of detecting the stated metabolites by (1)H NMR and LC/MS was demonstrated. Our data showed that a number of metabolites involved in glucose metabolism, citric acid cycle and amino acid metabolism were affected immediately after the intake of green tea. The proposed approach provided a more comprehensive picture of the metabolic changes after intake of green tea in human urine. The multiple analytical approach together with pattern recognition tools is a useful platform to study metabolic profiles after ingestion of botanicals and medicinal plants.     

Rapid Screening and Identification of Polar Constituents from Brazilian Arnica Lychnophora sp. by LC-UV/DAD-ESI-MS and LC-UV/DAD-ESI-MS/MS Analysis

This paper describes an analytical method for the rapid screening and identification of the phenolic constituents present in the polar extracts of different Lychnophora spp. using LC-UV/DAD-ESI-MS and LC-UV/DAD-ESI-MS/MS. Compounds were identified based on UV, retention time, MS experiments and MS/MS of precursor ion or standard. On-line phytochemical investigation of Lychnophora spp. allowed for the identification of flavonoids, chlorogenic acid derivatives and lactones. Some of the observed compounds were for the first time identified in Lychnophora species in a fast analytical procedure. The data obtained here may be helpful to the investigation of polar constituents from other Lychnophora species.     

Multilevel profiling and identification of Dalbergia odorifera and Dalbergia stevensonii by FTIR,NMR and GC/MS

Chemical differences of the extractives revealed by FTIR methods can be further confirmed by ¹H NMR and ¹³C NMR. Meanwhile, the volatile compounds in the extractives can be identified by GC/MS     

Methods of analysis for anthocyanins in plants and biological fluids

Anthocyanins are the largest group of water-soluble pigments in the plant kingdom. They are responsible for most of the red, blue, and purple colors of fruits, vegetables, flowers, and other plant tissues or products. The analysis of anthocyanins is complex as a result of their ability to undergo structural transformations and complexation reactions. In addition, they are difficult to measure independently of other flavonoids, as they have similar structural and reactivity characteristics. Anthocyanins are generally extracted with weakly acidified alcohol-based solvents, followed by concentration (under vacuum), and purification of the pigments. Paper and/or thin-layer chromatography and UV-Vis spectroscopy have traditionally been used for the identification of anthocyanins. Capillary zone electrophoresis, a hybrid of chromatography and electrophoresis, is gaining popularity for the analysis of anthocyanins; however, liquid chromatography (LC) has become the standard method for identification and separation in most laboratories and may be used for both preparative and quantitative analysis. LC with mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are possibly the most powerful methods for the structural elucidation of anthocyanins available, to date. At present, the most satisfactory method for mixture analysis is the multistep method of separation, isolation, and quantification by LC with peak identification by MS and high-field NMR.     

采用核磁共振/液相色谱-质谱异相关谱方法开展药用植物草棉活性提取物中多组分的同步结构分析研究

基于不完全分离分析策略,建立了NMR/LC-MS异相关谱(NMR/LC-MS HCS)方法对系列混合物样品的LC-MS和NMR谱数据的整合分析,发掘混合物图谱中来自同一组分的LC-MS和NMR谱数据间的内在相关性.以新疆维吾尔民族药用植物草棉(Gossypium herbaceam L.)花瓣的乙醇提取物(AB-8-2...     

A new iridoid diglycoside from Sambucus ebulus L

Abstract

The phytochemical examination of the polar constituents of Sambucus ebulus L. leaves led to the identification of patrinoside (1) and of a new diglycoside iridoid, patrinoside-aglycone-11-O-[β-D-glucopyranosyl-(1→6)-2′-deoxy-β-D-glucopyranoside] (trivially named as sambuloside) (2). Both of these structures have been assigned by spectroscopic means (NMR and MS).     

Purification of polar compounds from Radix isatidis using conventional C18 column coupled with polar-copolymerized C18 column

Regarding hydrophilic interaction chromatography and normal phase liquid chromatography, RPLC is another choice used to separate polar compounds with the improvement of polar-modified C18 stationary phase. In this study, a method using conventional C18 column coupled with polar-copolymerized C18 column was successfully developed for the separation and purification of polar compounds from Radix isatidis, which is one of the most commonly used traditional Chinese medicines (TCMs). An XTerra MS C18 column was used to fractionate the extract of R. isatidis and a homemade polar-copolymerized C18 column was utilized for the final purification due to its good separation selectivity and high resolution for polar compounds. The established purification system demonstrated good orthogonality for the polar compounds. As a result, ten compounds were purified and three of them were identified as 3-methyl-5-vinyloxazolidin-2-one (compound A), 5-hydroxymethyl-2-furaldehyde (compound B) and 3-methylfuran-2-carboxylic acid (compound G) based on the MS, IR and extensive NMR data, respectively. It was demonstrated to be a feasible and powerful technique for the purification of polar compounds under RPLC mode and more chemical information of TCMs will be obtained to interpret the efficiency of TCMs.     

Mass spectrometry assisted assignment of NMR resonances in reductively 13C-methylated proteins

Reductive 13C-methylation of proteins has been used as an isotope labeling strategy to study protein structure, function, and dynamics by nuclear magnetic resonance (NMR) spectroscopy. However, assigning the resulting 13C-dimethylamine peaks in a 1H-13C NMR spectrum has proved to be difficult, but it is important to expand the scope of the method. The assignment strategy presented here utilizes mass spectrometry (MS) for sequence identification and varying 13C/12C isotope ratios to correlate with NMR data. The site-specific reactivity of the lysines and N-terminal amine of a protein is exploited to produce a sample with varying 13C/12C ratios at each dimethylamine. MS and NMR are used to quantitate and correlate these ratios in order to assign peaks in the 1H-13C NMR spectrum. Hen egg white lysozyme was used as a model protein to demonstrate this assignment strategy.     

Detection and quantification of phenolic compounds in olive oil by high resolution H nuclear magnetic resonance spectroscopy

High resolution ¹H NMR spectroscopy has been employed as a versatile and rapid method to analyze the polar fraction of extra virgin olive oils containing various classes of phenolic compounds. The strategy for identification of phenolic compounds is based on the NMR chemical shifts of a large number of model compounds assigned by using two-dimensional (2D) NMR spectroscopy. Furthermore, 2D NMR was applied to phenolic extracts in an attempt to discover additional phenolic compounds. The ¹H NMR methodology was successful in detecting simple phenols, such as p-coumaric acid, vanillic acid, homovanillyl alcohol, vanillin, free tyrosol, and free hydroxytyrosol, the flavonols apigenin and luteolin, the lignans (+) pinoresinol, (+) 1-acetoxypinoresinol and syringaresinol, two isomers of the aldehydic form of oleuropein and ligstroside, the dialdehydic form of oleuropein and ligstroside lacking a carboxymethyl group, and finally total hydroxytyrosol and total tyrosol reflecting the total amounts of free and esterified hydroxytyrol and tyrosol, respectively. The absolute amount of each phenolic constituent was determined in the polar fraction by using anhydrous 1,3,5-triazine as an internal standard.     

傅立叶变换离子回旋共振质谱用于金属加工助剂中的成分分析

金属加工助剂是金属加工生产过程中必不可少的化工产品,其组成复杂,易形成螯合物干扰成分分析。该文利用傅立叶变换离子回旋共振质谱(Fourier transform ion cyclotron resonance mass spectrometry,FT-ICR MS)技术的高分辨性能,结合电感耦合等离子体质谱(ICP-MS)、红外光谱(IR)和核磁共振谱(NMR)对一种含未知成分的金属加工助剂进行成分分析。结果表明,该金属加工助剂中含有柠檬酸钠、乙二胺四乙酸(EDTA)与金属铋螯合物。该方法简便、准确,适用于含有金属螯合物的金属加工助剂成分的快速鉴定。     

Method development for fingerprinting of biodiesel blends by solid-phase extraction and gas chromatography-mass spectrometry

A method based on the combination of solid-phase extraction (SPE) with gas chromatography-mass spectrometry (GC/MS) for detailed chemical fingerprinting of biodiesel/petrodiesel blends was developed in the present study. Forensic identification, commonly referred to as chemical fingerprinting, is based on the relative distributions of individual aliphatic hydrocarbons, aromatic hydrocarbons, fatty acid alkyl esters, and free sterols. Fractionation of fuel samples is optimized for the separation of fatty acid esters and free sterols from petroleum hydrocarbons into four fractions: aliphatic, aromatic, fatty acid ester, and polar components. The final recoveries of aliphatic and aromatic hydrocarbons were determined to be in the range of 65-103%, 73-105% for FAMEs, and 78-103% for free sterols in the polar fraction. Excellent separation with negligible crossover of components with different polarities between fractions was observed. Quantitative analysis of blend levels and individual chemical distribution were achieved. The method has great potential for the identification of biodiesel in diesel fuel blends and could form the basis of a method for characterization of biodiesel-contaminated environmental samples.     

Analysis of Low-polar Ginsenosides in Steamed Panax Ginseng at High-temperature by HPLC-ESI-MS/MS

A high performance liquid chromatography coupled with electrospray ionization-tandem mass spectrometry( HPLC-ESI-MS/MS) method was developed for the analysis and identification of ginsenosides in the extracts of raw Panax ginseng(RPG) and steamed Panax ginseng at high temperatures(SPGHT). A total of 25 ginsenosides were extracted include of which 10 low-polar ginsenosides, such as ginsenosides F4, Rk3, Rh4, 20S-Rg3, 20R-Rg3 and so on, were identified according to their HPLC retention time and MS/MS data. The results indicated that the low polar ginsenosides were seldom found in RPG. For the exploration of the transformation pattern of the ginsenosides in steam processing, the standards of ginsenosides Re, Rg1, Rb1, Rc, Rb2, Rb3 and Rd were selected and hydrolyzed at a temperature of 120 ℃. The results show that these polar ginsenosides can be converted to low-polar ginsenosides such as Rg2, Rg6, F4, Rk3 and Rg5 by hydrolyzing the sugar chains.     

Synthesis of Highly Fluorinated Chloroformates and Their Use as Derivatizing Agents for Hydrophilic Compounds and Drinking‐Water‐Disinfection By‐Products

A rapid, safe, and efficient procedure was developed to synthesize, on a small scale, fluorinated chloroformates often required to perform analytical derivatizations. This new family of agents allows straightforward derivatization of highly polar compounds (with multiple hydroxy, carboxy, and amino substituents) in the aqueous phase, compatible with GC and GC/MS analysis. A goal of this work was to develop a derivatization procedure that would enable the detection and identification of highly polar disinfection by‐products in drinking water.     

Identification of ilaprazole metabolites in human urine by HPLC‐ESI‐MS/MS and HPLC‐NMR experiments

Ilaprazole is a new proton pump inhibitor designed for the treatment of gastric ulcers, and limited data is available on the metabolism of the drug. In this article, the structural elucidation of urinary metabolites of ilaprazole in human was described by HPLC‐ESI‐MS/MS and stopped‐flow HPLC‐NMR experiments. Urinary samples were precipitated by sodium carbonate solution, and then extracted by liquid–liquid extraction after adding ammonium acetate buffer solution. The enriched sample was separated using a C₁₈ reversed‐phase column with the mobile phase composed of acetonitrile and 0.05 mol/L ammonium acetate buffer solution in a gradient solution, and then directly coupled to ESI‐MS/MS detection in an on‐line mode or ¹H‐NMR (500 MHz) spectroscopic detection in a stopped‐flow mode. As a result, four sulfide metabolites, ilaprazole sulfide (M1), 12‐hydroxy‐ilaprazole sulfide (M2), 11,12‐dihydroxy‐ilaprazole sulfide (M3) and ilaprazole sulfide A (M4), were identified by comparing their MS/MS and NMR data with those of the parent drug and available standard compounds. The main biotransformation reactions of ilaprazole were reduction and the aromatic hydroxylation of the parent drug and its relative metabolites. The result testified that HPLC‐ESI‐MS/MS and HPLC‐NMR could be widely applied in detection and identification of novel metabolites. Copyright © 2010 John Wiley & Sons, Ltd.     

Strategies for continuous on-line high performance liquid chromatography coupled with diode array detection and electrospray tandem mass spectrometry for process monitoring of sulphonated azo dyes and their intermediates in anaerobic-aerobic bioreactors

On-line HPLC with diode array detection (DAD) coupled to electrospray tandem mass spectrometry (ESI-MS/MS) is presented as an integrated quality control and process integrated optimisation tool for the continuous monitoring of sulphonated azo dyes (SADs) and their intermediates in anaerobic and aerobic bioprocesses. Ion-pair RP-HPLC is found out to be more suitable for simultaneous monitoring of aromatic amines (AAs), sulphonated aromatic amines (SAAs) and sulphonated azo dyes in comparison to RP-HPLC with polar embedded phases. Monitoring of the anaerobic degradation of the diazo Reactive Black 5 displays the dependency of a two stage azo group reduction mechanism on the redox potential of the bioreactor. An autoxidation sensitive intermediate released from the anaerobic reduction is characterised by ESI-MS/MS for the first time. The functionality of the method is demonstrated by the control and evaluation of selective adaptation of bacteria to certain pollutants and the identification of unknown intermediates causing re-gaining colour released from azo dye treatment.     

Tentative identification of polar and mid‐polar compounds in extracts from wine lees by liquid chromatography–tandem mass spectrometry in high‐resolution mode

Sustainable agriculture has a pending goal in the revalorization of agrofood residues. Wine lees are an abundant residue in the oenological industry. This residue, so far, has been used to obtain tartaric acid or pigments but not for being qualitatively characterized as a source of polar and mid‐polar compounds such as flavonoids, phenols and essential amino acids. Lees extracts from 11 Spanish wineries have been analyzed by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) in high resolution mode. The high‐resolution power of LC–MS/MS has led to the tentative identification of the most representative compounds present in wine lees, comprising primary amino acids, anthocyans, flavanols, flavonols, flavones and non‐flavonoid phenolic compounds, among others. Attending to the profile and content of polar and mid‐polar compounds in wine lees, this study underlines the potential of wine lees as an exploitable source to isolate interesting compounds. Copyright © 2015 John Wiley & Sons, Ltd.