共查询到20条相似文献,搜索用时 0 毫秒
1.
液相色谱-同位素比质谱(LC-IRMS)是一种特征化合物同位素分析技术,该技术利用LC IsoLink接口设备实现液相色谱与同位素比质谱的联用,通过检测目标物质的稳定碳同位素比(δ13C),实现样品的产地来源与品质真实性鉴定。该文总结了IRMS与LC-IRMS技术的概况,以及过去20年LC-IRMS的发展历程;归纳整理了LC-IRMS在食品安全、生态与环境、生命科学及考古学等领域的应用情况;评述了LC-IRMS面临的技术局限、挑战及其未来的发展趋势。 相似文献
2.
Determination of priority organic micro-pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry 总被引:1,自引:0,他引:1
A multiclass method has been developed for screening, quantification and confirmation of organic micro-pollutants in water by gas chromatography coupled to mass spectrometry with a triple quadrupole analyzer. The work has been focused on the determination of more than 50 compounds belonging to different chemical families: 19 organochlorine and organophosphorus insecticides, 6 herbicides, 7 polychlorinated biphenyls, 16 polycyclic aromatics hydrocarbons, 2 brominated diphenyl ethers, and 3 octyl/nonyl phenols and pentachlorobenzene. Most of these analytes are included in the list of priority substances in the framework on European Water Policy.Analyte extraction was performed by solid phase extraction using C18 cartridges, and five isotopically labeled standards were added before extraction as surrogates. Analyses were performed by gas chromatography with tandem mass spectrometry (MS/MS) in electron impact mode. Accuracy and precision were evaluated by means of recovery experiments using water samples fortified at two concentration levels (25 and 250 ng L−1), with satisfactory results for most of analytes. The excellent selectivity and sensitivity reached in selected reaction monitoring mode allowed us satisfactory quantification and confirmation at levels as low as 25 ng L−1. Two MS/MS transitions were acquired for each analyte, using the Q/q intensity ratio as a confirmatory parameter. The method developed was applied to the analysis of surface, ground and wastewater samples collected from the Valencia Region (Spain).Analytical methodology using negative chemical ionization mode was also validated for the organochlorine compounds selected, showing a superior sensitivity and lower detection limits. 相似文献
3.
Geert Janssens Dirk Courtheyn Sven Mangelinckx Stéphanie Prévost Emmanuelle Bichon Fabrice Monteau Geert De Poorter Norbert De Kimpe Bruno Le Bizec 《Analytica chimica acta》2013
Although substantial technical advances have been achieved during the past decades to extend and facilitate the analysis of growth promoters in cattle, the detection of abuse of synthetic analogs of naturally occurring hormones has remained a challenging issue. When it became clear that the exogenous origin of steroid hormones could be traced based on the 13C/12C isotope ratio of the substances, GC/C/IRMS has been successfully implemented to this aim since the end of the past century. However, due to the costly character of the instrumental setup, the susceptibility of the equipment to errors and the complex and time consuming sample preparation, this method is up until now only applied by a limited number of laboratories. In this review, the general principles as well as the practical application of GC/C/IRMS to differentiate between endogenous steroids and exogenously synthesized homologous compounds in cattle will be discussed in detail, and will be placed next to other existing and to be developed methods based on isotope ratio mass spectrometry. Finally, the link will be made with the field of sports doping, where GC/C/IRMS has been established within the World Anti-Doping Agency (WADA) approved methods as the official technique to differentiate between exogenous and endogenous steroids over the past few years. 相似文献
4.
Guitton J Grand F Magat L Désage M Francina A 《Journal of mass spectrometry : JMS》2002,37(1):108-114
A simple method for the determination of nanomole amounts of (13)CO(2) generated from an in vitro reaction is reported. The incubation medium contains a known amount of unlabeled sodium bicarbonate and the gaseous (13)CO(2) enriches the atmosphere upon which a measurement of the isotopic enrichment ((13)CO(2)/(12)CO(2)) is made corresponding to a reverse isotope dilution. The quantification of the (13)CO(2) was performed by gas chromatography/isotope ratio mass spectrometry. This assay was validated in terms of linearity, accuracy and precision using three different substrates which produce (13)CO(2) either by enzymatic reaction [(13)C]urea, sodium [(13)C]formate) or by chemical reaction (sodium [(13)C]bicarbonate). Four calibration curves were tested for each (13)C-labeled substrate, allowing the quantification of (13)CO(2) from 25 pmol to 150 nmol. The dynamics of the assay were obtained as a function of the quantity of unlabeled sodium bicarbonate added to each sample. 相似文献
5.
Mathias Wind Helge Grunwald Klaus Gebhardt Klaus Illig Jochen Spickermann Claude Nuoffer Patrick Roussel Dominique Klauer Pascal Fullhardt Anne Schmitt-Hoffmann Michael Schleimer 《Journal of chromatography. A》2009,1216(18):3946-3953
The in vitro metabolic profile of BAL30630, an antifungal piperazine propanol derivative, which inhibits the 1,3-beta-d-glucansynthase, was investigated by incubation with microsomes of several species and with rat hepatocytes. For the spotting of the metabolites, mixtures of BAL30630 with a stable isotope (deuterium) labeled analogue were incubated. The metabolic pattern comprises several oxidized metabolites. Based on isotope exchange experiments, their structures could be assigned to epoxide- and hydroxylated metabolites. In hepatocyte incubations, several glucuronides formed from these oxidized metabolites could be observed. From the analysis of the metabolic pattern in microsomes, products of carbamate hydrolysis were characterized. This hydrolysis was highly species dependent. In activated incubations and in rat hepatocytes, those metabolites were further oxidized. In incubations without NADPH activation, the resulting hydrolytic metabolites could be enriched without the subsequent oxidation. Final structural elucidation of the metabolites was performed using accurate mass determination and isotope exchange experiments, in which incubations were analyzed by deuterium exchange and capillary HPLC–QTof-MS and MS/MS. The use of non-radioactive, stabile isotope labeled drug analogues in combination with isotope exchange studies was essential in particular for a defined assignment of the functional groups in the structures of the investigated metabolites. 相似文献
6.
José Robles-Molina 《Talanta》2010,82(4):1318-1324
In this work, we report the development and validation of an analytical method for the trace level determination of 14 selected (EU-directive) priority organic pollutants (namely, 1,2,3-trichlorobenzene (1,2,3-TCB), 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, hexachloro-1,3-butadiene, pentachlorobenzene, hexachlorobenzene, alachlor, α-hexachloro-cyclohexane (α-HCH), β-HCH, γ-HCH (lindane), δ-HCH, tetra-brominated diphenyl ether (tetra-BDE), penta-brominated diphenyl ether and hepta-brominated diphenyl ether) in wastewater samples from 5 different sewage treatment plants (STPs) located in Spain. The proposed methodology is based on liquid-liquid extraction with n-hexane followed by identification and confirmation of the selected pollutants by gas chromatography high-resolution mass spectrometry in selected ion recording acquisition mode. Recovery studies performed with spiked wastewater samples at two different concentration levels (0.1 and 1 μg L−1) gave mean recoveries in the range 80-120% (except for trichlorobenzenes, ca. with 50%) with RSD values below 10% in most cases, thus confirming the usefulness of the proposed methodology for the analyses of this kind of complex samples. The obtained detection limits in effluent wastewater matrices were in the low nanogram per liter range, with values as low as 0.09 ng L−1 for tetra-BDE and 0.3 ng L−1 for hexachlorobenzene. Finally, the proposed methodology was successfully applied to a monitoring study intended to characterize wastewater effluents of 5 different sewage treatment plants with different major activities (Industrial, Coastal, Urban). Most of the compounds targeted were detected in the ng L−1 range at concentrations ranging from 0.19 ng L−1 to 135 ng L−1 (hexachlorobenzene). 相似文献
7.
Toshiaki Yoshida 《Journal of chromatography. A》2009,1216(26):5069-5076
An analytical method was developed for the simultaneous measurement of 18 pyrethroids (allethrin, bifenthrin, cyfluthrin, cypermethrin, cyphenothrin, deltamethrin, empenthrin, fenpropathrin, furamethrin, imiprothrin, metofluthrin, permethrin, phenothrin, prallethrin, profluthrin, resmethrin, tetramethrin and transfluthrin) in indoor air. The pyrethroids were collected for 24 h using a combination of adsorbents (quartz fiber filter disk and Empore C18 disk), with protection from light, and then extracted with acetone, concentrated, and analyzed by GC/MS. They could be determined accurately and precisely (detection limits: ca. 1 ng/m3). The collected pyrethroid samples could be stored for up to one month at 4 °C in a refrigerator. 相似文献
8.
Authenticity assessment of flavoured strawberry foods was performed using headspace-solid phase microextraction (HS-SPME) coupled to gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). An authenticity range was achieved, investigating on the carbon isotope ratio of numerous selected aroma active volatile components (methyl butanoate, ethyl butanoate, hex-(2E)-enal, methyl hexanoate, buthyl butanoate, ethyl hexanoate, hexyl acetate, linalool, hexyl butanoate, octyl isovalerate, γ-decalactone and octyl hexanoate) of organic Italian fresh strawberries. To the author's knowledge, this is the first time that all these components were investigated simultaneously by GC-C-IRMS on the same sample. The results were compared, when applicable, with those obtained by analyzing the HS-SPME extracts of commercial flavoured food matrices. In addition, one Kenyan pineapple and one fresh Italian peach were analyzed to determine the δ(13)C(VPDB) of the volatile components common to strawberry. The δ(13)C(VPDB) values are allowed to differentiate between different biogenetic pathways (C(3) and CAM plants) and more interestingly between plants of the same CO(2) fixation group (C(3) plants). Additional analyses were performed on all the samples by means of Enantioselective Gas Chromatography (Es-GC), measuring the enantiomeric distribution of linalool and γ-decalactone. It was found that GC-C-IRMS and Es-GC measurements were in agreement to detect the presence of non-natural strawberry aromas in the food matrices studied. 相似文献
9.
Martínez Ocaña R Mena Granero A Egea Gonzalez FJ Garrido Frenich A Martínez Vidal JL Plaza Bolaños P 《Analytical and bioanalytical chemistry》2008,390(5):1413-1423
A multiresidue method for determining 22 polychlorinated biphenyls (PCBs) in air has been developed and validated by gas chromatography
(GC) coupled to tandem mass spectrometry (MS/MS) using a triple quadrupole analyzer (QqQ). The method was validated in terms
of both steps of sampling and analysis. The sampling method, which is based on active sampling using polyurethane foam (PUF)
as adsorbent, was validated by generating standard atmospheres. The retention capacity of this sampling sorbent allows up
to 5 m3 of air to be sampled without any breakthrough for most compounds. Two solvent extraction methods were compared: sonication
and Soxhlet extraction with a mixture of n-hexane:diethyl ether (95:5 v/v). Both extraction methods yielded similar results, but the first one required less solvent
and time. The method exhibited good accuracy (80.3–99.8%), precision (2.2–15.2%) and lower limits that allowed quantification
and confirmation at levels as low as 0.008 ng/m3. Finally, the method was applied to the analysis of PCBs in the air in areas near to a municipal solid-waste landfill and
directly above the refuse in the landfill, where it indicatedd the presence of some of the target compounds.
Figure General chemical structure of polychlorinated biphenyls 相似文献
10.
液相色谱/元素分析-同位素比值质谱联用法鉴定蜂蜜掺假 总被引:8,自引:0,他引:8
采用液相色谱/元素分析-同位素比值质谱联用法(LC/EA-IRMS)对国内蜂蜜掺假情况进行了研究。基于测定得到的38个纯正蜂蜜样品的碳同位素δ13C值数据,提出了纯正蜂蜜样品的δ13C值要求: 蛋白质和蜂蜜的δ13C差值(Δδ13CP-H)≥~0.95‰,果糖和葡萄糖的δ13C差值(Δδ13CF-G)在~0.64‰至0.53‰范围内,各个组分间的δ13C最大差值(Δδ13Cmax)<2.09‰。对150个日常检测样品、蜂农和蜂蜜供应商的蜂蜜样品分别采用本文建立的LC/EA-IRMS和国家标准方法(EA-IRMS)进行鉴定,LC/EA-IRMS方法检出58个掺有C3或C4植物糖浆的阳性样品,而EA-IRMS方法仅检出7个掺有C4植物糖浆的阳性样品,可见新方法大大提高了对蜂蜜掺假的鉴别能力。 相似文献
11.
12.
Determination of phthalate esters in Chinese spirits using isotope dilution gas chromatography with tandem mass spectrometry 下载免费PDF全文
Jing Wang Xiaomin Li Qinghe Zhang Jinping Xiong Hongmei Li 《Journal of separation science》2015,38(10):1700-1710
Phthalate esters are additives used in polyvinylchloride and are found as contaminants in many food products. An isotope dilution mass spectrometry technique has been developed for accurate analysis of 16 phthalate esters in Chinese spirits by adopting the 16 corresponding isotope‐labeled phthalate esters. The ethanol in the spirit sample was first removed by heating with a water bath at 100°C with a stream of nitrogen, after which the residue was extracted with n‐hexane twice. The phthalates collected were identified and quantified by gas chromatography with tandem mass spectrometry in multiple reaction monitoring mode. The spiking recoveries of 16 analytes ranged from 94.3 to 105.3% with relative standard deviation values of <6.5%. The detection limits for 16 analytes were <10.0 ng/g. The expanded relative uncertainties were from 3.0 to 14%. A survey was performed on Chinese spirits from the market. Six of the nine analyzed samples were contaminated by phthalates. Di‐n‐butyl phthalate and di‐2‐ethylhexyl phthalate showed higher detection frequency and concentrations. This isotope dilution gas chromatography with tandem mass spectrometry method is simple, rapid, accurate, and highly sensitive, which qualifies as a candidate reference method for the determination of phthalates in spirits. 相似文献
13.
Methyl-branched fatty acids (MBFAs) are the dominant form of fatty acid found in many bacteria. They are also found at low
levels in a range of foodstuffs, where their presence has been linked to bacterial sources. In this study we evaluated the
potential of compound-specific isotope analysis to obtain insights into the stable carbon isotope ratios (δ13C values in ‰) of individual MBFAs and to compare them to the stable carbon isotope ratios of straight-chain fatty acids in
food. Due to their low abundance in foodstuffs, the MBFAs were enriched prior to gas chromatography coupled to isotope ratio
mass spectrometric (GC–IRMS) analysis. After transesterification, urea complexation was used to suppress the 16:0 and 18:0
methyl esters that were dominant in the samples. Following that, silver-ion high performance liquid chromatography was used
to separate the saturated from the unsaturated fatty acids. The resulting solutions of saturated fatty acids obtained from
suet, goat’s milk, butter, and human milk were studied by GC–IRMS. The δ13C values of fatty acids with 12–17 carbons ranged from −25.4‰ to −37.6‰. In all samples, MBFAs were most depleted in carbon-13,
followed by the odd-chain fatty acids 15:0 and 17:0. 14:0 and 16:0 contained the highest proportions of carbon-13. The results
from this study illustrate that MBFAs have distinctive δ13C values and must originate from other sources and/or from very different substrates. These measurements support the initial
hypothesis that δ13C values can be used to attribute MBFAs to particular sources. 相似文献
14.
Patrick J. A. Hill Neil R. Banerjee Arshad Ali Iffat Jabeen Gordon R. Osinski Fred J. Longstaffe 《Journal of mass spectrometry : JMS》2019,54(8):667-675
We present a procedure for the determination of the isotopic ratios of silicon and oxygen from the same aliquot of anhydrous silicate material. The sample is placed in a bromine pentafluoride atmosphere as it is heated with a CO2 laser system releasing silicon tetrafluoride and oxygen gasses. The oxygen gas is then purified to remove other reaction by‐products through several liquid nitrogen traps before being captured onto a molecular sieve and transferred to an isotope ratio mass spectrometer. The silicon tetrafluoride gas is then purified using a supplementary line by repeatedly freezing to ?196°C with liquid nitrogen and then thawing with an ethanol slurry at ?110°C through a series of metal and Pyrex traps. The purified gas is then condensed into a Pyrex sample tube before it is transferred to an isotope ratio mass spectrometer for silicon isotope ratio measurements. This system has silicon yields of greater than 90% for pure quartz, olivine, and garnet standards and has a reproducibility of ±0.1‰ (2σ) for pure quartz for both oxygen and silicon isotope measurements. Meteoritic samples were also successfully analyzed to demonstrate this system's ability to measure the isotopic ratio composition of bulk powders with precision. This unique technique allows for the fluorination of planetary material without the need for wet chemistry. Though designed to analyze small aliquots of meteoritic material (1.5 to 3 mg), this approach can also be used to investigate refractory terrestrial samples where traditional fluorination is not suitable. 相似文献
15.
In the last decade compound-specific stable isotope analysis (CSIA) has evolved as a valuable technique in the field of environmental
science, especially in contaminated site assessment. Instrumentation and methods exist for highly precise measurements of
the isotopic composition of organic contaminants even in a very low concentration range. Nevertheless, the determination of
precise and accurate isotope data of environmental samples can be a challenge. Since CSIA is gaining more and more popularity
in the assessment of in situ biodegradation of organic contaminants, an increasing number of authorities and environmental
consulting offices are interested in the application of the method for contaminated site remediation. Because of this, it
is important to demonstrate the problems and limitations associated with compound-specific isotope measurements of environmental
samples. In this review, potential pitfalls of the analytical procedure are critically discussed and strategies to avoid possible
sources of error are provided. In order to maintain the analytical quality and to ensure the basis for reliable stable isotope
data, recommendations on groundwater sampling, and sample preservation and storage are given. Important aspects of sample
preparation and preconcentration techniques to improve sensitivity are highlighted. Problems related to chromatographic resolution
and matrix interference are discussed that have to be considered in order to achieve accurate gas chromatography/isotope ratio
mass spectrometry measurements. As a result, the need for a thorough investigation of compound-specific isotope fractionation
effects introduced by any step of the overall analytical method by standards with known isotopic composition is emphasized.
Finally, we address some important points that have to be considered when interpreting data from field investigations.
Figure CSIA Principal (Carbon) 相似文献
16.
A gas chromatography-tandem quadrupole mass spectrometry (GC-MS/MS) method for the determination of twelve priority pesticides, and transformation products (e.g. metabolites) specified in the EU Baby Food Directive 2003/13/EC is described. Prior to GC-MS/MS analysis, co-extractives were removed from acetonitrile extracts using dispersive solid phase extraction with octadecyl (200 mg) and primary secondary amine (50 mg) sorbents. The clean up proved essential for the satisfactory long-term chromatographic performance during the analysis of a range of representative commercially pre-prepared baby food samples. Extracts spiked with pesticides at 1-8 microg kg(-1), yielded average recoveries in the range 60-113% with relative standard deviations less than 28%. 相似文献
17.
18.
A precise and accurate stable isotope dilution liquid chromatography/tandem mass spectrometry method for the analysis of intracellular homocysteine has been developed. An internal standard, [(2)H(8)]-homocystine, was added to cell pellets from EA.hy 926 cells grown in culture under low and high folate concentrations. D,L-dithiothreitol was used to reduce cellular homocystine to homocysteine. Cellular proteins were precipitated by the addition of formic acid in acetonitrile. After centrifugation, a portion of the supernatant was analyzed by liquid chromatography/tandem mass spectrometry. Using a Supelcosil cyano column with an Applied Biosystems API 4000 triple quadrupole mass spectrometer, the SRM transitions for homocysteine (m/z 136 to m/z 90) and [(2)H(4)]-homocysteine (m/z 140 to m/z 94) were monitored. The method was validated by conducting five replicate analyses on three different days at four different concentrations (concentrations at the lower limit of quantitation and expected lower quartile, mid-range and upper quartile). The limit of detection was 2 ng/10(6) EA.hy 926 cells. Using this method, the intracellular homocysteine concentration in EA.hy 926 cells ranged from 10 to 36 ng/10(6) cells. 相似文献
19.
We report a method for determining plasma und urinary [(15)N]urea enrichments in an abundance range between 0.37 and 0.52 (15)N atom% (0-0.15 atom% excess (APE) (15)N) using a dimethylaminomethylene derivative. Compared with conventional off-line preparation and (15)N analysis of urea, this method requires only small sample volumes (0.5 ml of plasma and 25 microl of urine). The (15)N/(14)N ratio of urea derivatives was measured by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Two peaks were separated; one was identified by gas chromatography/mass spectrometry (GC/MS) as the complete derivatized urea. Calibration of the complete urea derivative was performed by linear regression of enrichment values of known standard mixtures. Replicate standard (6-465 per thousand delta(15)N) derivatizations showed a relative standard deviation ranging from 0.1 to 7%. In order to test the feasibility of the method, human subjects and rats ingested a single meal containing either 200 mg of [(15)N]glycine (95 AP (15)N) or 0.4 mg of [(15)N]-alpha-lysine (95 AP (15)N), respectively. Urine and plasma were collected at hourly intervals over 7 h after the meal intake. After (15)N glycine intake, maximum urinary urea (15)N enrichments were 330 and 430 per thousand delta(15)N (0.12 and 0.16 APE (15)N) measured by GC/C/IRMS, whereas plasma [(15)N]glycine enrichments were 2.5 and 3.3 APE (15)N in the two human subjects 2 h after the meal. (15)N enrichments of total urine and urine samples devoid of ammonia were higher enriched than urinary [(15)N]urea measured by GC/C/IRMS, reflecting the presence of other urinary N-containing substances (e.g. creatinine). In rats plasma urea (15)N enrichments were 15-20 times higher than those in urinary urea (10-20 per thousand delta(15)N). The different [(15)N]urea enrichments observed after ingestion of [(15)N]-labeled glycine and lysine confirm known differences in the metabolism of these amino acids. 相似文献
20.
建立了氨基酸同位素稀释液相色谱-串联质谱法准确测定合成肽段绝对含量的方法。实验中对合成肽段的纯度进行了表征,色谱纯度表征结果为99%以上,质谱纯度为90%以上。在肽段溶液中加入13C标记的氨基酸后进行酸溶液水解时间的优化,水解后的氨基酸直接经液相色谱分离和质谱检测,结果表明肽段中的被测氨基酸在150 ℃、6 mol/L HCl溶液水解4~6 h就可以达到水解平衡。每个肽段选择两个或两个以上的被测氨基酸,测得随机选择的5种合成肽段的绝对含量为62.07%~88.18%,测定结果的相对标准偏差小于8%,相对误差小于5%,均满足定量要求。除常用的被测氨基酸苯丙氨酸、缬氨酸、异亮氨酸外,还考察了选择赖氨酸和精氨酸作为被测氨基酸的可行性,实验结果表明增加精氨酸为被测氨基酸是可行的,从而进一步增加了方法的普适性。该方法的建立避免了色谱法定量时氨基酸衍生化处理带来的副反应影响及操作繁琐等问题,提高了肽段含量测定的准确度和精密度,为肽段含量的准确测定提供了一种新的方法。 相似文献