PubAg

Main content area

You searched for: Subject "isotope dilution technique" Remove constraint Subject: "isotope dilution technique"
Start Over

Search

1,325  Search Results

« Previous | 1 - 20 of 1,325 |
Number of results to display per page

Search Results

1. Re-certification of hydroxyvitamin D standards by isotope pattern deconvolution

Author:
Pitarch-Motellón, J.; Roig-Navarro, A.F.; Le Goff, C.; Cavalier, E.; Fabregat-Cabello, N.
Source:
Journal of chromatography 2019 v.1120 pp. 89-94
ISSN:
1570-0232
Subject:
isotope dilution technique,   etc   ; blood serum; humans; isotopes; liquid chromatography; mass spectrometry; metabolites; vitamin D;     Show all 8 Subjects
Abstract:
... Vitamin D testing in analytical clinical laboratories has been experiencing a rapid increase of demand over the last years, as it plays a key role in several disorders. Due to the narrow ranges of medical significance regarding its concentration levels in human serum, accurate and precise determinations of vitamin D metabolites are required.We present an isotope dilution mass spectrometry quantifi ...
DOI:
10.1016/j.jchromb.2019.04.043

2. Eliminating Preparation of Multisample External Calibration Curves and Dilution of Study Samples Using the Multiple Isotopologue Reaction Monitoring (MIRM) Technique in Quantitative LC-MS/MS Bioanalysis

Author:
Gu, Huidong; Zhao, Yue; DeMichele, Marissa; Zheng, Naiyu; Zhang, Yan J.; Pillutla, Renuka; Zeng, Jianing
Source:
Analytical chemistry 2019 v.91 no.13 pp. 8652-8659
ISSN:
1520-6882
Subject:
isotope dilution technique,   etc   ; biomarkers; isotope labeling; isotopes; liquid chromatography; liquid-liquid extraction; monitoring; tandem mass spectrometry;     Show all 8 Subjects
Abstract:
... Preparation of multisample external calibration curves and dilution of study samples are critical steps in bioanalytical sample processing for quantitative liquid chromatography–tandem mass spectrometry (LC-MS/MS) based bioanalysis of small-molecule compounds, biotherapeutics, and biomarkers, but they can be time-consuming and prone to error. It is highly desired to simplify or eliminate these two ...
DOI:
10.1021/acs.analchem.9b02136

3. Glutamine Side Chain ¹³C═¹⁸O as a Nonperturbative IR Probe of Amyloid Fibril Hydration and Assembly

Author:
Wu, Haifan; Saltzberg, Daniel J.; Kratochvil, Huong T.; Jo, Hyunil; Sali, Andrej; DeGrado, William F.
Source:
Journal of the American Chemical Society 2019 v.141 no.18 pp. 7320-7326
ISSN:
1520-5126
Subject:
isotope dilution technique,   etc   ; amyloid; glutamine; hydrogen bonding; infrared spectroscopy; isotope labeling; models; neurodegenerative diseases; peptides; toxicity;     Show all 10 Subjects
Abstract:
... Infrared (IR) spectroscopy has provided considerable insight into the structures, dynamics, and formation mechanisms of amyloid fibrils. IR probes, such as main chain ¹³C═¹⁸O, have been widely employed to obtain site-specific structural information, yet only secondary structures and strand-to-strand arrangements can be probed. Very few nonperturbative IR probes are available to report on the side- ...
DOI:
10.1021/jacs.9b00577

4. Development of a fast and efficient analytical technique for the isotopic analysis of fission and actinide elements in environmental matrices

Author:
Roach, Benjamin D.; Fenske, Emilie K.; Ilgner, Ralph H.; Hexel, Cole R.; Haverlock, Tamara J.; Giaquinto, Joseph M.
Source:
Journal of chromatography 2019 v.1587 pp. 155-165
ISSN:
0021-9673
Subject:
isotope dilution technique,   etc   ; actinides; automation; ion exchange chromatography; platinum; rapid methods; rare earth elements; spectrometers; uncertainty;     Show all 9 Subjects
Abstract:
... An automated separation–direct analysis scheme has been developed to determine both the concentration and isotopic composition of a suite of elements down to the low picogram level in a complex silicon-based matrix. With the ultimate goal of performing rapid analysis of materials with non-natural isotopic compositions, RAPID (Rapid Analysis of Post-Irradiation Debris) consists of a high-pressure i ...
DOI:
10.1016/j.chroma.2018.12.029

5. Strategies for Accurate Quantitation of Volatiles from Foods and Plant-Origin Materials: A Challenging Task

Author:
Sgorbini, Barbara; Cagliero, Cecilia; Liberto, Erica; Rubiolo, Patrizia; Bicchi, Carlo; Cordero, Chiara
Source:
Journal of agricultural and food chemistry 2019 v.67 no.6 pp. 1619-1630
ISSN:
1520-5118
Subject:
isotope dilution technique,   etc   ; chamomile; chromatography; foods; furans; gases; headspace analysis; solvents; stable isotopes;     Show all 9 Subjects
Abstract:
... The volatile fraction of foods and of plant-origin materials provides functional information on sample-related variables, and gas-phase extractions are ideal approaches for its accurate chemical characterization. However, for gas-phase sampling, the usual procedures adopted to standardize results from solvent extraction methods are not appropriate: headspace (HS) composition depends on the intrins ...
DOI:
10.1021/acs.jafc.8b06601

6. Critical assessment of hexavalent chromium species from different solid environmental, industrial and food matrices

Author:
Séby, F.; Vacchina, V.
Source:
Trends in analytical chemistry 2018 v.104 pp. 54-68
ISSN:
0165-9936
Subject:
isotope dilution technique,   etc   ; chromium; food matrix; soil; wastes;     Show all 5 Subjects
Abstract:
... The accurate determination of Cr(VI), the most hazardous form of chromium, is an analytical challenge because of its facility to be reduced during all steps of the analytical procedure. This review presents a synthesis of the available studies for the analysis of Cr species in different solid samples (soils/wastes, working atmosphere, industrial and food samples). A particular attention has been p ...
DOI:
10.1016/j.trac.2017.11.019

7. Simultaneous detection of 4(5)-methylimidazole and acrylamide in biscuit products by isotope-dilution UPLC-MS/MS

Author:
Wu, Chunjian; Wang, Li; Guo, Xiaobing; Li, He; Yu, Shujuan
Source:
Food control 2019 v.105 pp. 64-70
ISSN:
0956-7135
Subject:
isotope dilution technique,   etc   ; acrylamides; chemical species; methanol; monitoring; reversed-phase liquid chromatography; tandem mass spectrometry; ultra-performance liquid chromatography; uncertainty;     Show all 9 Subjects
Abstract:
... An ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous analysis of 4(5)-methylimidazole (4-MI) and acrylamide (AA) in biscuit products. The samples were extracted with methanol followed by dispersive primary secondary amine clean-up. The analytes were separated by reverse phase liquid chromatography, detected by tandem mass spect ...
DOI:
10.1016/j.foodcont.2019.04.039

8. Selenoneine is a major selenium species in beluga skin and red blood cells of Inuit from Nunavik

Author:
Achouba, Adel; Dumas, Pierre; Ouellet, Nathalie; Little, Matthew; Lemire, Mélanie; Ayotte, Pierre
Source:
Chemosphere 2019 v.229 pp. 549-558
ISSN:
0045-6535
Subject:
isotope dilution technique,   etc   ; Inuit; demethylation; erythrocytes; foods; liquid chromatography; marine mammals; metabolites; methylation; selenium; tandem mass spectrometry; toxicity; Quebec;     Show all 13 Subjects
Abstract:
... Nunavimmiut (Inuit of Nunavik, Northern Quebec, Canada) exhibit a high selenium (Se) status because of their frequent consumption of marine mammal foods. Indirect evidence from our previous studies had suggested that selenoneine – a novel selenocompound – may be accumulating in the blood of Nunavimmiut. We used a liquid-chromatography/inductively coupled tandem mass spectrometry (LC-ICP-MS/MS) met ...
DOI:
10.1016/j.chemosphere.2019.04.191

9. Concentration of mercury species in hair, blood and urine of individuals occupationally exposed to gaseous elemental mercury in Asturias (Spain) and its comparison with individuals from a control group formed by close relatives

Author:
Queipo-Abad, Silvia; González, Pablo Rodríguez; Martínez-Morillo, Eduardo; Davis, W. Clay; García Alonso, José Ignacio
Source:
The Science of the total environment 2019 v.672 pp. 314-323
ISSN:
0048-9697
Subject:
isotope dilution technique,   etc   ; accidents; blood; fish consumption; heat exchangers; mercury; methylmercury compounds; occupational exposure; seafoods; urine; zinc; Spain;     Show all 12 Subjects
Abstract:
... Between November 19th, 2012 and December 3rd, 2012, 50 workers were intoxicated with gaseous Hg in San Juan de Nieva (Asturias, Spain) during the maintenance of a heat exchanger of a zinc manufacturer. We have quantified the concentration of methylmercury (MeHg), ethylmercury (EtHg) and Hg(II) in blood, hair and urine samples of those individuals taken three years after the accident. Blood, hair a ...
DOI:
10.1016/j.scitotenv.2019.03.367

10. Characterization of the Key Aroma Compounds in the Crust of Soft Pretzels by Application of the Sensomics Concept

Author:
Schoenauer, Sebastian; Schieberle, Peter
Source:
Journal of agricultural and food chemistry 2019 v.67 no.25 pp. 7110-7119
ISSN:
1520-5118
Subject:
isotope dilution technique,   etc   ; air; aldehydes; breads; color; ethanol; flavor; lipids; odor compounds; odors; pastries; phenylacetic acid; pyrazines; stable isotopes;     Show all 14 Subjects
Abstract:
... Soft pretzels show a uniform brown crust color and elicit a characteristic aroma that is clearly different from those of other small types of bread. Data on the odorants responsible for this unique aroma are scarcely available. Application of aroma extract dilution analysis (AEDA) on an extract (distillate) obtained from the crust of freshly baked soft pretzels followed by identification experimen ...
DOI:
10.1021/acs.jafc.9b02601

11. GC-ICP-MS/MS Instrumental Setup for Total and Speciation Sulfur Analysis in Gasolines using Generic Standards

Author:
Freije-Carrelo, Laura; García-Bellido, Javier; Calderón-Celis, Francisco; Moldovan, Mariella; Encinar, Jorge Ruiz
Source:
Analytical chemistry 2019 v.91 no.11 pp. 7019-7024
ISSN:
1520-6882
Subject:
isotope dilution technique,   etc   ; chromatography; detection limit; detectors; flow injection analysis; gasoline; petroleum; quantitative analysis; reference standards; sulfur; tandem mass spectrometry;     Show all 11 Subjects
Abstract:
... Quantitative characterization of sulfur-containing petroleum derivatives is mainly limited by the large number of potential targets present and the matrix effects suffered due to the high-carbon-containing matrices. Herein we describe the instrumental modifications required in a commercial GC-ICP-MS/MS instrument, and their corresponding optimization, for turning it into a compound-independent qua ...
DOI:
10.1021/acs.analchem.9b01199

12. Viruslike Element-Tagged Nanoparticle Inductively Coupled Plasma Mass Spectrometry Signal Multiplier: Membrane Biomarker Mediated Cell Counting

Author:
Yuan, Rong; Ge, Fuchun; Liang, Yong; Zhou, Yang; Yang, Limin; Wang, Qiuquan
Source:
Analytical chemistry 2019 v.91 no.8 pp. 4948-4952
ISSN:
1520-6882
Subject:
isotope dilution technique,   etc   ; atomic absorption spectrometry; bacteriophages; biomarkers; early diagnosis; folate receptors; multipliers; nanoparticles; neoplasm cells; neoplasms;     Show all 10 Subjects
Abstract:
... Although rare cancerous cells are considered as more objective indications for a precise early diagnosis of cancers, accurate counting of them still is a spirited challenge. We reported a signal multiplication strategy by constructing element-tagged viruslike nanoparticles (VLNPs) with a precise number of atoms for a membrane biomarker mediated higher sensitive cell counting using inductively coup ...
DOI:
10.1021/acs.analchem.9b00749

13. Characterization of the Flavor Properties of Dark Chocolates Produced by a Novel Technological Approach and Comparison with Traditionally Produced Dark Chocolates

Author:
Chetschik, Irene; Pedan, Vasilisa; Chatelain, Karin; Kneubühl, Markus; Hühn, Tilo
Source:
Journal of agricultural and food chemistry 2019 v.67 no.14 pp. 3991-4001
ISSN:
1520-5118
Subject:
isotope dilution technique,   etc   ; acids; aldehydes; chocolate; cluster analysis; esters; flavor; odor compounds; odors; pyrazines; sensory evaluation; stable isotopes;     Show all 12 Subjects
Abstract:
... Dark chocolates produced by a novel technological approach (NCs) were characterized in comparison with those traditionally produced (TCs) by sensory evaluation, gas chromatography-olfactometry in combination with aroma extract dilution analysis, quantitation of the aroma-relevant chocolate odorants by stable isotope dilution assays, and calculation of the odor activity values (OAVs). The results o ...
DOI:
10.1021/acs.jafc.8b06800

14. Characterization of the Key Aroma Compounds in Yeast Dumplings by Means of the Sensomics Concept

Author:
Sahin, Buket; Schieberle, Peter
Source:
Journal of agricultural and food chemistry 2019 v.67 no.10 pp. 2973-2979
ISSN:
1520-5118
Subject:
isotope dilution technique,   etc   ; dough; evaporation; flavor; odor compounds; odors; phenylethyl alcohol; solvents; stable isotopes; starch; vanillin; wheat; yeasts;     Show all 13 Subjects
Abstract:
... The key odorants in the volatile fraction isolated from a steamed yeasted wheat dough (yeast dumpling) by solvent assisted flavor evaporation (SAFE) were characterized by an aroma extract dilution analysis (AEDA). The 29 aroma-active compounds were located within the flavor dilution (FD) factor range of 8–512. Among them, the highest FD factors were found for 2- and 3-methylbutanoic acid, 4-hydrox ...
DOI:
10.1021/acs.jafc.9b00556

15. Key Odorants from the Fermentation Broth of the Edible Mushroom Ischnoderma resinosum

Author:
Wickramasinghe, Purni C. K.; Munafo, John P.
Source:
Journal of agricultural and food chemistry 2019 v.67 no.7 pp. 2036-2042
ISSN:
1520-5118
Subject:
isotope dilution technique,   etc   ; Ischnoderma; benzaldehyde; culture media; flavor; liquid state fermentation; mushrooms; odor compounds; odors; stable isotopes;     Show all 10 Subjects
Abstract:
... Eighteen odorants were identified by applying aroma extract dilution analysis in the liquid fermentation broth of the edible mushroom Ischnoderma resinosum (P. Karst). Eight compounds with flavor dilution factors ≥16 were quantitated in a 16-day sample using stable isotope dilution assays. Odor activity values (OAV) revealed anise-smelling 4-methoxybenzaldehyde (OAV; 1639), vanilla-smelling 3,4-di ...
DOI:
10.1021/acs.jafc.8b06766

16. Determination of elevated levels of nitrate in vegetable powders by high-precision isotope dilution GC–MS

Author:
Pagliano, Enea; Mester, Zoltán
Source:
Food chemistry 2019
ISSN:
0308-8146
Subject:
isotope dilution technique,   etc   ; antioxidant activity; beets; drying; gas chromatography-mass spectrometry; headspace analysis; kale; nitrates; powders; spinach;     Show all 10 Subjects
Abstract:
... A high-precision isotope dilution GC–MS method was employed for the determination of nitrate in processed vegetables. The samples were extracted in water, derivatized with triethyloxonium tetrafluoroborate and analyzed by headspace GC–MS (15 samples/hour). The method was applied to estimate the effect of drying on the content of nitrate in vegetables. The absolute amount of nitrate in a spinach sa ...
DOI:
10.1016/j.foodchem.2019.02.048

17. Complete validation according to current international criteria of a confirmatory quantitative method for the determination of nitrofuran metabolites in seafood by liquid chromatography isotope dilution tandem mass spectrometry

Author:
Øye, Britt Elin; Couillard, Felicia Dawn; Valdersnes, Stig
Source:
Food chemistry 2019 v.300 pp. 125175
ISSN:
0308-8146
Subject:
isotope dilution technique,   etc   ; Codex Alimentarius; Crustacea; fatty fish; food production; imports; liquid chromatography; metabolites; nitrofurantoin; quantitative analysis; seafoods; tandem mass spectrometry; washing;     Show all 13 Subjects
Abstract:
... Despite the ban of nitrofurans (NFs) for use in food production in many countries in the 1990s, NF metabolites in food are still regularly detected during import control testing. We have developed a confirmatory routine method for the detection and quantification of NF metabolites in seafood using LC-MS/MS and validated the method according to the strict criteria in European legislation and Codex ...
DOI:
10.1016/j.foodchem.2019.125175

18. Post-mortem diagnosis of kidney impairment: An experimental study

Author:
Maskell, Peter D.; Penney, Elizabeth; Smith, Paul R.; Hikin, Laura J.; Morley, Stephen R.
Source:
Forensic science international 2019 v.301 pp. 271-277
ISSN:
0379-0738
Subject:
isotope dilution technique,   etc   ; creatinine; death; drug excretion; drugs; epidemiology; glomerular filtration rate; ketosis; kidney diseases; kidneys; mass spectrometry; metabolites; necropsy; toxicity;     Show all 14 Subjects
Abstract:
... The determination of the role that drugs may have played in a death is an important part of the investigation into unexplained deaths. Renal impairment may lead to a reduction in drug excretion rate and therefore an accumulation of drugs or metabolites, leading to possible toxic or lethal effects. Creatinine levels are known to be stable in the post mortem period and in life can give an indication ...
DOI:
10.1016/j.forsciint.2019.05.034

19. Quantitation of benzene in flavourings and liquid foods containing added cherry-type flavour by a careful work-up procedure followed by a stable isotope dilution assay

Author:
Frank, Stephanie; Hofmann, Thomas; Schieberle, Peter
Source:
European food research & technology 2019 v.245 no.8 pp. 1605-1610
ISSN:
1438-2377
Subject:
isotope dilution technique,   etc   ; benzaldehyde; benzene; carcinogenicity; cherries; drinking water; flavor; flavorings; food research; foods; liquids; odor compounds; raw materials; solid phase microextraction; stable isotopes;     Show all 15 Subjects
Abstract:
... The exposure of humans to the aromatic hydrocarbon benzene should be minimized due to its carcinogenicity. Previous studies have reported on the presence of benzene, in particular in foods with added cherry aroma compounds, in particular benzaldehyde. To allow a reliable quantitation of benzene, a stable isotope dilution assay using (²H₃)benzene as the internal standard was developed and solid pha ...
DOI:
10.1007/s00217-019-03267-3

20. A quantitative method to detect human exposure to sulfur and nitrogen mustards via protein adducts

Author:
Pantazides, Brooke G.; Quiñones-González, Jennifer; Rivera Nazario, Danisha M.; Crow, Brian S.; Perez, Jonas W.; Blake, Thomas A.; Johnson, Rudolph C.
Source:
Journal of chromatography 2019 v.1121 pp. 9-17
ISSN:
1570-0232
Subject:
isotope dilution technique,   etc   ; Lewis acids; biomarkers; blood serum; cysteine; humans; liquid chromatography; nitrogen; peptidase K; proteins; quantitative analysis; solid phase extraction; sulfur; tandem mass spectrometry; tripeptides;     Show all 15 Subjects
Abstract:
... Sulfur and nitrogen mustards are internationally banned vesicants listed as Schedule 1 chemical agents in the Chemical Weapons Convention. These compounds are highly reactive electrophiles that form stable adducts to a variety of available amino acid residues on proteins upon exposure. We present a quantitative exposure assay that simultaneously measures agent specific protein adducts to cysteine ...
DOI:
10.1016/j.jchromb.2019.05.005