共查询到20条相似文献,搜索用时 62 毫秒
1.
H Kidwell J J Jones D E Games 《Rapid communications in mass spectrometry : RCM》2001,15(14):1181-1186
Five polar herbicides were separated and characterised using high-speed analytical countercurrent chromatography (HSACCC) in conjunction with online electrospray mass spectrometry (ESI-MS). The countercurrent chromatography used a standard isocratic biphasic solvent system of hexane/ethyl acetate/methanol/water in reverse phase to effect the separation of these five environmentally important compounds. The chromatograph was coupled to a triple quadrupole mass spectrometer via a standard electrospray liquid chromatography interface that was able to give mass spectra in negative ion mode of each compound. Limits of detection are reported for this series of compounds along with representative negative ion ESI-MS data and calibrations for the separation. 相似文献
2.
Analysis of sub-ppb levels of polynuclear aromatic hydrocarbons (PAHs) in drinking water by high performance liquid chromatography (HPLC) fluorescence detection typically requires large water samples and lengthy extraction procedures. The detection itself, although selective, does not give compound identity confirmation. Benchtop gas chromatography/mass spectrometry (GC/MS) systems operating in the more sensitive selected ion monitoring (SIM) acquisition mode discard spectral information and, when operating in scanning mode, are less sensitive and scan too slowly. The selectivity of hyperthermal surface ionisation (HSI), the high column flow rate capacity of the supersonic molecular beam (SMB) GC/MS interface, and the high acquisition rate of time-of-flight (TOF) mass analysis, are combined here to facilitate a rapid, specific and sensitive technique for the analysis of trace levels of PAHs in water. This work reports the advantages gained by using the GC/HSI-TOF system over the HPLC fluorescence method, and discusses in some detail the nature of the instrumentation used. 相似文献
3.
Dudley E El-Sharkawi S Games DE Newton RP 《Rapid communications in mass spectrometry : RCM》2000,14(14):1200-1207
In order to optimise the analysis of urinary nucleosides by high performance liquid chromatography/mass spectrometry (HPLC/MS), the HPLC separation of these compounds was performed at different 'flow rates' and 0.2mL/min was found to give both a better separation and ionisation. The ionisation conditions were optimised to give the best intensity of the molecules quasi-molecular ions. The ion distribution profile and ionisation in both positive and negative mode were examined and the detection of the protonated molecule in positive mode chosen for further analysis. The limits of detection of the method developed are reported and representative LC/MS and LC/MS/MS spectra shown. Typical urinary nucleoside chromatograms are presented. 相似文献
4.
Thomas J. P. Smyth Virginia Rodríguez Robledo W. Franklin Smyth 《Rapid communications in mass spectrometry : RCM》2010,24(5):651-658
Oxazepam has been subjected to controlled degradation at 100°C for 3 h in 0.5 M HCl and 0.5 M NaOH. Following neutralisation of the degradation mixture and removal of salts by solid‐phase extraction (SPE), isocratic high‐performance liquid chromatography/mass spectrometry (HPLC/MS) using water/methanol (25:75 v/v) as the mobile phase was carried out using a flow diverter to collect fractions prior to their characterisation by electrospray ionisation multi‐stage mass spectrometry (ESI‐MSn) and proposal of the corresponding fragmentation patterns. The elemental compositions of the degradation products and their MS fragments were evaluated using electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry (ESI‐QTOF‐MS/MS) which was then used to support the proposed fragmentation patterns. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
5.
In this study we present a high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) method which has been elaborated to analyse steroid hormones, hormone conjugates, oral contraceptives and macrolide antibiotics unchanged in unfiltered influents and effluents of sewage treatment plants (STPs). HPLC separation of the steroid hormones was achieved in 35 min, as well as those of the antibiotics. The analytes were extracted by solid-phase extraction, followed by clean-up using size exclusion chromatography (SEC). For the final quantification HPLC/MS/MS was used. The two ionisation modes, electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI), in HPLC/MS/MS were compared for the analysis of steroid hormones. For quantitative results drastic matrix effects were observed while using ESI. These effects were less pronounced while using APCI. These pitfalls were additionally reduced by clean-up using SEC as well as isotope dilution. Additionally, two multiple reaction monitoring (MRM) transitions per compound were used to prevent false positive results. Recovery experiments with spiked tap water with concentrations varying from 1 to 1000 ng/L gave constant recovery rates: The recovery rates for the hormones and conjugates ranged from 58 to 107%, those of the contraceptives ranged from 83 to 109%. The relative standard deviation was found to be 7 to 24% and the limits of detection were 0.1 to 4.5 ng/L. The recovery rates of the macrolide antibiotics ranged from 76 to 103%, while the relative standard deviation was found to be 7 to 14% and the limits of detection ranged from 0.6 to 1.8 ng/L. The maximum concentrations found in influents of a STP was 470 ng/L for estriol and 1200 ng/L for erythromycin. 相似文献
6.
Ocsana Opriş Maria-Loredana Soran Virginia Coman Florina Copaciu Dumitru Ristoiu 《Central European Journal of Chemistry》2013,11(8):1343-1351
This study is focused on the determination of some important antibiotics from different classes in waste water samples using solid phase extraction followed by high performance liquid chromatography with two detectors, diode array and mass spectrometer in positive ionisation mode. The investigated antibiotics include three penicillins (amoxicillin, ampicillin, penicillin G), two cephalosporins (ceftazidime, ceftriaxone), and two tetracyclines (tetracycline, doxycycline). The studied antibiotics were extracted from waste water samples using hydrophilic-lipophilic balanced cartridges. The extraction of antibiotics from water matrices was tested at several pH values. The best recoveries were obtained at pH 3 and 7 respectively. Depending on the nature of antibiotic, the limits of detection and quantification were obtained in the range of 0.07–0.92 µg mL?1 and 0.21–2.77 µg mL?1 respectively. Influent and effluent waste water samples were collected from a Waste Water Treatment Plant from Romania in order to detect the studied antibiotics. The antibiotics detected in the influent waste water samples were ceftriaxone (334 µg L?1), tetracycline (146 µg L?1) and doxycycline (110 µg L?1). In effluent waste water samples no target antibiotics were detected. 相似文献
7.
Erik Tengstrand Johan Rosén Karl-Erik Hellenäs K. Magnus Åberg 《Analytical and bioanalytical chemistry》2013,405(4):1237-1243
A generic method to screen for new or unexpected contaminants at ppm levels in food has been developed. The method comprises an acidic acetonitrile extraction, detection with ultra-high-pressure liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry and statistical evaluation using a metabolomics approach comparing suspected contaminated food with uncontaminated foods. The method was tested for 26 model contaminants from 100 μg/g down to 0.4 μg/g in three brands of fresh orange juice. Blinded statistical evaluation revealed signals from all added contaminants detectable by liquid chromatography–electrospray ionisation using positive ionisation mode, while only two false-positive signals were reported. The method is primarily intended to be used for investigation of food samples suspected to be contaminated with unknown substances. Additionally it could be used to continuously monitor for appearance of new food contaminants as a complement to the specific targeted analysis that is today’s foundation of food safety analysis. 相似文献
8.
Kammerer B Kahlich R Ufer M Laufer S Gleiter CH 《Rapid communications in mass spectrometry : RCM》2004,18(4):458-464
Phenprocoumon is a commonly used oral anticoagulant of the coumarin type, and has found extensive clinical use in the treatment of thrombophlebitis, pulmonary embolism and atrial fibrillation. In the course of a clinical study to investigate the influence of genetic polymorphisms of the CYP2C9 enzyme on phenprocoumon metabolism, we developed a new enantioselective liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/MS/MS) method to quantify (R)- and (S)-phenprocoumon in human plasma. HPLC separation of the enantiomers was achieved on a Chira-Grom-2 column under isocratic conditions using a water/acetonitrile/formic acid eluent. For detection and quantification a triple-quadrupole MS system was used in the selected reaction monitoring (SRM) mode. As an internal standard the structurally homologous compound warfarin was chosen. The detector response was linear with a correlation coefficient of 0.988-0.999 for (R)-phenprocoumon and 0.989-0.999 for (S)-phenprocoumon in the investigated concentration range between 62.5 and 1000 ng/mL (per enantiomer). The limit of detection (LOD) was 12.5 ng/mL. 相似文献
9.
Effects of common metal ions on the determination of anions by suppressed ion chromatography 总被引:3,自引:0,他引:3
A rapid and sensitive method for the determination of domperidone in plasma was developed, using high-performance liquid chromatographic separation with tandem mass spectrometry detection. The samples were rendered basic with 1 M Na2CO3 and the domperidone extracted using tert.-butyl methyl ether, followed by back-extraction into formic acid (2% in water). Chromatography was performed on a Phenomenex Luna C8 (2), 5 microm, 150x2 mm column with a mobile phase consisting of acetonitrile-0.02% formic acid (300:700, v/v), delivered at 0.2 ml/min. Detection was performed using an Applied Biosystems Sciex API 2000 mass spectrometer set at unit resolution in the multiple reaction monitoring mode. TurbolonSpray ionisation was used for ion production. The mean recovery of domperidone was +/- 100%, with a lower limit of quantification set at 0.189 ng/ml. This assay method makes use of the increased sensitivity and selectivity of tandem mass spectrometric detection resulting in a rapid (extraction and chromatography) and sensitive method for the determination of domperidone in human plasma, which is more sensitive than previously described methods. 相似文献
10.
Liquid chromatography multi-stage mass spectrometry for the analysis of 5-hydroxymethylfurfural in foods 总被引:2,自引:0,他引:2
A new, simple and selective method for the analysis of 5-hydroxymethylfurfural (HMF) in foods by liquid chromatography coupled to ion trap multi-stage mass spectrometry (LC-MS(n)) is proposed in the present study. Several chromatographic columns were tested and the best results were obtained using a phenyl fluorinated column. MS conditions were established using an atmospheric pressure chemical ionisation (APCI) source in the positive ionisation mode. MS/MS was used for quantitative analysis while MS(3) was required for confirmation purposes. Quality parameters such as day-to-day and run-to-run precision (RSD<10%) and detection limit (133 ng g(-1), 333 pg injected) were established. This method was successfully applied to the analysis of HMF content in several Spanish food samples from a local market. 相似文献
11.
Ding S Dudley E Plummer S Tang J Newton RP Brenton AG 《Rapid communications in mass spectrometry : RCM》2006,20(18):2753-2760
A reversed-phase high-performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS) method was developed and validated for the simultaneous determination of ten major active components in Ginkgo biloba extract (bilobalide, ginkgolides A, B, C, quercetin, kaempferol, isorhamnetin, rutin hydrate, quercetin-3-beta-D-glucoside and quercitrin hydrate) which have not been previously reported to be quantified in a single analysis. The ten components exhibit baseline separation in 50 min by C18 chromatography using a water/1:1 (v/v) methanol/acetonitrile gradient. Quantitation was performed using negative ESI-MS in selected ion monitoring (SIM) mode. Good reproducibility and recovery were obtained by this method. The sensitivity of both UV and different mass spectrometry modes (full scan, selected ion monitoring (SIM), and selected reaction monitoring (SRM)) were compared and both quantitation with and without internal standard were evaluated. The analysis of Ginkgo biloba commercial products showed remarkable variations in the rutin and quercetin content as well as the terpene lactone contents although all the products satisfy the conventional quality control method. 相似文献
12.
E. Destandau A. Toribio M. Lafosse V. Pecher C. Lamy P. André 《Journal of chromatography. A》2009,1216(9):1390-1394
Xanthones are well known for their interesting phytochemical properties, which make them attractive to the pharmaceutical and medicinal industry. We have therefore developed a method to analyse the major xanthones in Garcina mangostana. The xanthones were extracted by pressurized liquid extraction with ethanol and separated at the semi-preparative scale by centrifugal partition chromatography (CPC) with a biphasic solvent system consisting of heptane/ethyl acetate/methanol/water (2:1:2:1, v/v/v/v). A CPC-electrospray ionisation MS coupling was performed and used to simultaneously separate and identify the compounds. Thanks to a variable flow splitter and an additional stream of ethanol/1 mol L−1 ammonium acetate (95:5, v/v), all the compounds were ionised, detected and monitored whatever the solvents used in mobile phase for the CPC separation. The dual mode or elution–extrusion which are less solvent-consuming and faster than the elution mode were used without loss of ionisation and detection. 相似文献
13.
H. Bagheri J. Slobodnik R. M. Marce Recasens R. T. Ghijsen U. A. Th. Brinkman 《Chromatographia》1993,37(3-4):159-167
Summary Trace enrichment on a precolumn packed with copolymer material, coupled on-line with reversed-phase, column liquid chromatography-particle beammass spectrometry (RPLC-PB-MS) has been used for both target and non-target analysis of water samples. RPLC is carried out on a C-18-bonded silica column using a linear acetonitrile-0.1 M ammonium acetate gradient. Using optimised PB-MS conditions and 100–250 ml water samples, the detection limits for several phenylureas are in the 0.03–0.05 g l–1 range using the full-scan mode; repeatability is good and the LC-PB-MS system is robust. Several surface and drinking water samples have been analysed and low levels of various environmental contaminants have been identified using electron impact mass spectra. Applying chemical ionisation with methane as reagent gas in both the positive and negative mode in conjunction with PB-MS provides relevant confirmatory information. 相似文献
14.
Piraud M Vianey-Saban C Petritis K Elfakir C Steghens JP Morla A Bouchu D 《Rapid communications in mass spectrometry : RCM》2003,17(12):1297-1311
The diagnosis of inherited disorders of amino acids (AA) metabolism is usually performed on automated analysers by ion-exchange chromatography and quantification after ninhydrin derivatisation of about 50 different AA. A single run liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for these molecules can be an alternative to this time-consuming technique. The first step of this development is the infusion study of the fragmentation of 79 molecules of biological interest in electrospray ionisation tandem mass spectrometry (ESI-MS/MS), in positive and in negative ionisation mode. Among them, three molecules can be detected only in negative ionisation mode, 38 only in positive mode and 38 in the two modes. All the most abundant fragmentations are presented, with optimisation of the MS/MS parameters. The positive ionisation mode was retained for the simultaneous analysis of 76 molecules. One sensitive and/or specific transition is proposed for the monitoring of each molecule. Improvement in sensitivity of detection was obtained with the use of an acidic mobile phase. Flow injection analysis studies led us to highlight a number of interferences-due to isobaric molecules, to in-source collision-induced dissociation, or to natural isotopic distribution of the elements-which are listed. For a reliable quantification method, these molecules have to be separated by LC before analysis in the tandem mass spectrometer. Ion-pairing reversed-phase liquid chromatography (RPLC) using perfluorinated carboxylic acids as ion-pairing agents has already been found suitable for analysis of AA in MS/MS positive ionisation mode and is under development. 相似文献
15.
Rivera HM Walker GS Sims DN Stockham PC 《European journal of mass spectrometry (Chichester, England)》2003,9(6):599-607
A sensitive and selective high-performance liquid chromatography/atmospheric pressure chemical ionisation tandem mass spectrometry (HPLC/APCI-MS/MS) method for the simultaneous detection of 18 benzodiazepines and metabolites in human blood is described. The procedure utilises butyl chloride extraction at alkaline pH followed by reversed-phase liquid chromatography. The technique is suitable for screening analyses and confirmation of identity of the benzodiazepines at their lowest reported therapeutic concentrations using 500 microL of blood. The method has been successfully applied in forensic cases involving low concentrations of benzodiazepines. 相似文献
16.
Marcela Castro-Benitez 《液相色谱法及相关技术杂志》2017,40(18):921-929
To isolate chlorophyll from grass extract by means of high-speed countercurrent chromatography, a solvent system composed of n-hexane–dichloromethane–ethanol–water 4:2:6:2 (v/v/v/v) was applied. The isolation of chlorophylls a, b, and pheophytins a, b was successfully performed from grass when dichloromethane was part of the solvent system. Comparatively, when chloroform is part of the stationary phase instead of dichloromethane, the xanthophyll separation showed better resolution compared to chlorophylls. Through the solvent system, we could demonstrate the meaningful difference of polarity between dichloromethane, a polar aprotic solvent, and chloroform, a non-polar solvent. Therefore, n-hexane–dichloromethane–ethanol–water 4:2:6:2 (v/v/v/v) is adequate for chlorophylls separation because it changes the system to yield more polarity. This hypothesis supports the fact that the elution mode length was 10?hr and the extrusion mode 2?hr, whereas with chloroform the elution mode length was 7?hr and the extrusion mode 4?hr. Online high-performance liquid chromatography in conjunction with atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) was suitable to identify xanthophylls and chlorophylls fractions by means of mass spectra in positive (+) mode. Structure elucidation of chlorophylls and pheophytins was done by nuclear magnetic resonance (NMR) 1D/2D-NMR experiments. 相似文献
17.
Pichini S Pellegrini M Pacifici R Marchei E Murillo J Puig C Vall O García-Algar O 《Rapid communications in mass spectrometry : RCM》2003,17(17):1958-1964
A high-performance liquid chromatography (HPLC) method with mass spectrometric detection is described for determination of arecoline in newborn meconium, urine and cord serum, using pilocarpine as internal standard. The analytes were extracted from neonatal biological matrices with chloroform/isopropanol (95:5, v/v) at alkaline pH. Extracts were analyzed by HPLC coupled to an electrospray (ESI) interface and a quadrupole mass spectrometer. Chromatography was performed on a C(8) reversed-phase column using 10 mM ammonium acetate (pH 4.3)/acetonitrile (90:10, v/v) as mobile phase. The mass spectrometer was operated in selected ion monitoring mode. The method was validated over the concentration range 0.005-1.00 micro g/g meconium, 0.004-1.00 micro g/mL cord serum and 0.001-1.00 micro /mL urine. Mean recoveries ranged between 86.5 and 90.7% for arecoline in the different biological matrices, with precision always better than 10%. The quantification limits of arecoline were 0.005 micro g/g meconium, 0.004 micro g/mL cord serum, and 0.001 micro g/mL urine. The method was applied to the analysis of neonatal biological matrices to assess eventual fetal exposition to arecoline. Two newborns from Asian mothers who declared areca nut consumption presented arecoline in meconium with concentrations in the range 0.006-0.008 micro g/g; also the urine from one neonate tested positive for the drug. 相似文献
18.
Delmulle B De Saeger S Adams A De Kimpe N Van Peteghem C 《Rapid communications in mass spectrometry : RCM》2006,20(5):771-776
The development of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of 16 mycotoxins possibly related to the 'Sick Building Syndrome' on filters and in fungal cultures is described. Fungi-surface sampling as regards the 'Sick Building Syndrome' preferably happens by scraping off fungal material and vacuuming onto cellulose filters. Therefore, these two media were used as samples. They were spiked with nivalenol, deoxynivalenol, zearalenone, diacetoxyscirpenol, T-2 toxin, verrucarol, verrucarin A, neosolaniol, sterigmatocystin, roridin A, ochratoxin A, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2, which can be produced by isolates from fungi-damaged buildings. Deepoxy-deoxynivalenol was used as internal standard. Samples were extracted with organic solvents and the different mycotoxins were separated by high-performance liquid chromatography (HPLC) using a C18 reversed-phase SunFire analytical column and a mobile phase of variable mixtures of ammonium acetate (10 mM) and sodium acetate (20 microM) in water (solvent A) and in methanol (solvent B). The samples were run on-line with a Micromass Quattro Micro triple quadrupole mass spectrometer in positive electrospray ionisation mode using multiple reaction monitoring (MRM). The detection limits of the procedure varied from 50 to 0.009 pg/microL for filter samples and from 75 to 0.04 pg/microL for fungal culture samples. As the method includes few and non-labourious sample treatment steps, it should allow for a high throughput of samples. 相似文献
19.
A high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry (HPLC/ESI-MS/MS) method has been developed for the simultaneous determination of eflucimibe, a powerful acyl-coenzyme A cholesterol O-acyltransferase (ACAT) inhibitor, and its main metabolites, in plasma. The ESI and MS/MS parameters were investigated and optimised for each of the four compounds in the positive ion mode. Plasma samples were deproteinised by precipitation with acetonitrile and directly analysed by HPLC/ESI-MS/MS in less than 4 min. Quantitation was performed in the multiple reaction monitoring (MRM) mode for highest sensitivity, selecting the protonated molecules [M+H](+) as precursor ions. The method was demonstrated to be specific and sensitive, and a linear response was observed within a 1-25 ng/mL concentration range. Correlation coefficients (r(2)) greater than 0.9960 were obtained by least-squares regression, and limits of detection down to 0.2 ng/mL were calculated. Therefore, this HPLC/ESI-MS/MS method appears to be an efficient tool, able to provide valuable information for a pharmacological purpose. 相似文献
20.
Schmidt AC Herzschuh R Matysik FM Engewald W 《Rapid communications in mass spectrometry : RCM》2006,20(15):2293-2302
In order to develop a liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) method for identification and quantification of polar metabolites of explosives using a triple quadrupole system, the mass spectrometric ionisation and fragmentation behaviour of different nitrophenols, nitro- and aminonitrobenzoic acids, nitrotoluenesulfonic acids, and aminonitrotoluenes was investigated. Due to their different molecular structures, the substances concerned showed a very different ionisation efficiency in the ESI process. Interestingly, 2,4-dinitrobenzoic acid yielded no mass signals in the Q1 scan suggesting a thermal decarboxylation in the ion source, whereas the corresponding 3,5-isomer showed a high ionisation yield. Using negative ionisation polarity, carboxylic, phenolic, and sulfonic acid groups were deprotonated resulting in molecular anions, which could be fragmented in a collision cell. A pronounced dependency of the produced fragment ion series on the kind and position of substituents at the nitrobenzene ring (ortho effects) was observed and exploited for the development of substance-specific detection methods in the multiple reaction monitoring mode. In case of benzoic and sulfonic acids, decarboxylation and desulfonation, respectively, were observed as the most frequent fragmentation reactions. Furthermore, besides loss of NO(2), NO fragmentation occurred and preceded a decarbonylation of the benzene ring. The expulsion of the open-shell molecules NO and NO(2) led to a variety of distonic radical anions. 相似文献