U.S. flag

An official website of the United States government

PubAg

Main content area

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

Search

1,590  Search Results

« Previous | 1 - 20 of 1,590 |
Number of results to display per page

Search Results

1. Legacy and emerging per- and polyfluoroalkyl substances (PFASs) in Australian biosolids

Author:
Moodie, Damien; Coggan, Timothy; Berry, Kathryn; Kolobaric, Adam; Fernandes, Milena; Lee, Elliot; Reichman, Suzie; Nugegoda, Dayanthi; Clarke, Bradley O.
Source:
Chemosphere 2021 v.270 pp. 129143
ISSN:
0045-6535
Subject:
isotope dilution technique,   etc   ; biosolids; industrial wastes; perfluorocarbons; phosphates; sulfonates; watersheds;     Show all 7 Subjects
Abstract:
... Biosolids samples were collected from 19 Australian WWTPs during 2018 that cover a range of catchment types (urban, rural, industrial waste discharges) and treatment technologies. Samples were analysed for 44 PFAS using isotope dilution and alkaline extraction coupled with quantification with LC-MS/MS. The Σ₄₄PFAS mean concentration was 260 ng/g dry weight (dw) and ranged between 4.2 and 910 ng/g ...
DOI:
10.1016/j.chemosphere.2020.129143

2. Furfuryl alcohol is a precursor for furfurylthiol in coffee

Author:
Cerny, Christoph; Schlichtherle-Cerny, Hedwig; Gibe, Romelo; Yuan, Yuan
Source:
Food chemistry 2021 v.337 pp. 128008
ISSN:
0308-8146
Subject:
isotope dilution technique,   etc   ; cations; food chemistry; furfural; furfuryl alcohol; odor compounds; oxidation; stable isotopes;     Show all 8 Subjects
Abstract:
... This study investigated the role of furfuryl alcohol (FFA) in the formation of furfurylthiol (FFT), the most important odorant in roasted coffee, using in-bean and spiking experiments. Green beans were spiked with FFA, and after roasting FFT was quantified by stable isotope dilution analysis. The FFT level in the roasted beans increased dose-dependently with addition of FFA. Additionally, beans we ...
DOI:
10.1016/j.foodchem.2020.128008

3. Polychlorinated naphthalenes (PCNs) in food products in Latvia: Congener-specific analysis, occurrence, and dietary exposure of the general population

Author:
Zacs, D.; Perkons, I.; Pasecnaja, E.; Bartkevics, V.
Source:
Chemosphere 2021 v.264 pp. 128460
ISSN:
0045-6535
Subject:
isotope dilution technique,   etc   ; body weight; carbon; chemical species; dietary exposure; fish; toxicity; toxicology; Latvia;     Show all 9 Subjects
Abstract:
... A study was performed to evaluate the dietary exposure of the Latvian population to polychlorinated naphthalenes (PCNs). Based on the toxicological characteristics, provisional levels of occurrence, congener patterns, and the availability of analytical standards, twenty-six congeners were included in the analysis. Considering the planar structure of PCNs, an analytical protocol on the basis of des ...
DOI:
10.1016/j.chemosphere.2020.128460

4. A new highly enriched 233U reference material for improved simultaneous determination of uranium amount and isotope amount ratios in trace level samples

Author:
Essex, Richard M.; Williams, Ross W.; Rogers, Kayron T.; Hexel, Cole R.; Parsons-Davis, Tashi; Treinen, Kerri C.
Source:
Talanta 2021 v.221 pp. 121638
ISSN:
0039-9140
Subject:
isotope dilution technique,   etc   ; atomic absorption spectrometry; ion exchange; mass spectrometry; plutonium; radionuclides; reference standards; titration; uranium;     Show all 9 Subjects
Abstract:
... A highly-enriched ²³³U reference material (>0.99987 n(²³³U)/n(U)) has been prepared and characterized for use as an isotope dilution mass spectrometry spike. An ion exchange separation was performed on 1 g of high purity ²³³U to further reduce trace amounts of contaminant Pu in the material. The purified ²³³U was then prepared as a master solution which was analyzed for molality of uranium by modi ...
DOI:
10.1016/j.talanta.2020.121638

5. Trends and Levels of Perfluorinated Compounds in Soil and Sediment Surrounding a Cluster of Metal Plating Industries

Author:
Na, Situ; Hai, Reti; Wang, Xiaohui; Li, Nankun
Source:
Soil & sediment contamination 2021 v.30 no.4 pp. 423-435
ISSN:
1549-7887
Subject:
isotope dilution technique,   etc   ; organic carbon; perfluorooctane sulfonic acid; perfluorooctanoic acid; sediment contamination; sediments; soil; ultra-performance liquid chromatography;     Show all 8 Subjects
Abstract:
... The occurrence of 16 perfluorinated compounds (PFCs) in soil and sediment from the surroundings of a metal plating industrial park was investigated. The PFCs were quantified using isotope dilution ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS). The ranges of the most commonly detected nine PFCs were 1.71–16.3 ng g⁻¹ dry weight (dw) and 4. ...
DOI:
10.1080/15320383.2020.1863908

6. Stand out from matrix: Ultra-sensitive LC−MS/MS method for determination of histamine in complex biological samples using derivatization and solid phase extraction

Author:
Hu, Xiaolan; Bian, Xiqing; Gu, Wan-Yi; Sun, Baoqing; Gao, Xiang; Wu, Jian-Lin; Li, Na
Source:
Talanta 2021 v.225 pp. 122056
ISSN:
0039-9140
Subject:
isotope dilution technique,   etc   ; anaphylaxis; asthma; blood serum; derivatization; histamine; humans; ionization; mast cells; patients; sampling; solid phase extraction;     Show all 12 Subjects
Abstract:
... The determination of low abundant endogenous components is a challenge for the clinical samples. Histamine, a crucial endogenous component, fulfils various regulatory and mediatory functions in human, and the change of content is a critical index for the diagnosis of some diseases, especially allergy, asthma, and anaphylactic shock. However, it is challenging to detect histamine because of the low ...
DOI:
10.1016/j.talanta.2020.122056

7. Determination of seventeen free amino acids in human urine and plasma samples using quadruple isotope dilution mass spectrometry combined with hydrophilic interaction liquid chromatography – Tandem mass spectrometry

Author:
Öztürk Er, Elif; Özbek, Belma; Bakırdere, Sezgin
Source:
Journal of chromatography 2021 v.1641 pp. 461970
ISSN:
0021-9673
Subject:
isotope dilution technique,   etc   ; chemical species; detection limit; humans; hydrophilic interaction chromatography; isotopes; tandem mass spectrometry; urinalysis; urine;     Show all 9 Subjects
Abstract:
... Taking into account the growing demand for new analytical procedures that are appropriate for analysis of complex biological samples with increased sensitivity, accuracy and precision, a novel analytical method was described for the determination of underivatized amino acids in human plasma and urine samples. The presented analytical procedure involved the direct analysis of urine samples and the ...
DOI:
10.1016/j.chroma.2021.461970

8. A novel isotope dilution UHPLC-ESI-MS/MS method for the quantification of 3-monochloropropane-1,2-diol in Caco-2 cell transport and receiving buffers

Author:
Zhao, Yang; Araujo, Magali; Flynn, Thomas J.; Mapa, Mapa S.T.; Mossoba, Miriam E.; Sprando, Robert L.
Source:
Food additives & contaminants 2021 v.38 no.3 pp. 361-370
ISSN:
1944-0057
Subject:
isotope dilution technique,   etc   ; acetic acid; acetonitrile; alpha-chlorohydrin; electrospray ionization mass spectrometry; human cell lines; intestinal secretions; tandem mass spectrometry;     Show all 8 Subjects
Abstract:
... A routine, selective and sensitive ultra-high performance liquid chromatography-electrospray ionisation tandem triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS) method was developed and validated for the quantification of 3-monochloropropane-1,2-diol (3-MCPD) in Caco-2 cell transport buffer (FaSSIF-V2, the second version of a fasted state simulated intestinal fluid) and receiving buffer (HBSS, ...
DOI:
10.1080/19440049.2021.1873426

9. Determination of 3-iodothyronamine (3-T1AM) in mouse liver using liquid chromatography-tandem mass spectrometry

Author:
Li, Zhong-Min; Miller, Manuel; Gachkar, Sogol; Mittag, Jens; Schriever, Sonja C.; Pfluger, Paul T.; Schramm, Karl-Werner; De Angelis, Meri
Source:
Journal of chromatography 2021 v.1165 pp. 122553
ISSN:
1570-0232
Subject:
isotope dilution technique,   etc   ; detection limit; ligands; liquid chromatography; liver; metabolites; mice; pharmacodynamics; stable isotopes; tandem mass spectrometry; thyroxine;     Show all 11 Subjects
Abstract:
... 3-iodothyronamine (3-T₁AM) has been suggested as a novel chemical messenger and potent trace amine-associated receptor 1 ligand in the CNS that occurs naturally as endogenous metabolite of the thyroid hormones. Discrepancies and variations in 3-T₁AM plasma and tissue concentrations have nonetheless caused controversy regarding the existence and biological role of 3-T₁AM. These discussions are at l ...
DOI:
10.1016/j.jchromb.2021.122553

10. Simultaneous Determination of Acrylamide, 5-Hydroxymethylfurfural, and Heterocyclic Aromatic Amines in Thermally Processed Foods by Ultrahigh-Performance Liquid Chromatography Coupled with a Q Exactive HF-X Mass Spectrometer

Author:
Gao, Jing-Xuan; Qin, Lei; Wen, Shu-Yao; Huang, Xu-Hui; Dong, Xiu-Ping; Zhou, Da-Yong; Zhu, Bei-Wei
Source:
Journal of agricultural and food chemistry 2021 v.69 no.7 pp. 2325-2336
ISSN:
1520-5118
Subject:
isotope dilution technique,   etc   ; acrylamides; chemical species; computer software; electrospray ionization mass spectrometry; food chemistry; hydroxymethylfurfural; spectrometers; ultra-performance liquid chromatography;     Show all 9 Subjects
Abstract:
... In this study, a rapid and reliable method based on ultrahigh-performance liquid chromatography coupled with Q Exactive HF-X mass spectrometry (UHPLC-QE/MS) was established for the simultaneous quantification and validation of acrylamide, 5-hydroxymethylfurfural, and 14 heterocyclic aromatic amines in thermally processed foods. With the optimization of the pretreatment method, all 16 hazardous com ...
DOI:
10.1021/acs.jafc.0c06743

11. The Dynamic of Nitrogen Uptake from Different Sources by Pea (Pisum sativum L.)

Author:
Wysokinski, Andrzej; Lozak, Izabela
Source:
Agriculture (Basel) 2021 v.11 no.1
ISSN:
2077-0472
Subject:
isotope dilution technique,   etc   ; Pisum sativum; agriculture; cultivars; dynamics; fertilizers; flowers; isotopes; length; nitrogen; peas; research; root nodules; soil; temperature;     Show all 15 Subjects
Abstract:
... Nitrogen uptake from various sources by plants capable of biological reduction of N₂ in symbiotic systems with root nodule bacteria is influenced by many factors. The aim of the study was to examine the influence of the development stage and variety of pea (Pisum sativum L.) cultivated in years with different temperature and precipitation conditions on the dynamics of nitrogen uptake from the atmo ...
DOI:
10.3390/agriculture11010081

12. Characterizing the emissions of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) from electric arc furnaces during steel-making

Author:
Shen, Xuejing; Yang, Qiuting; Shen, Jia; Yang, Lili; Wang, Minxiang; Yang, Yuanping; Liu, Guorui
Source:
Ecotoxicology and environmental safety 2021 v.208 pp. 111722
ISSN:
0147-6513
Subject:
isotope dilution technique,   etc   ; dibenzofuran; dioxins; ecotoxicology; electric arc; gas chromatography; mass spectrometry; quantitative analysis; steel; temperature; toxicity; China;     Show all 12 Subjects
Abstract:
... The amount of steel produced using electric arc furnaces (EAFs) has been increasing in recent years. In this study, stack gases from EAFs in steelmaking plants were analyzed to determine if they are also dominant sources of polybrominated dibenzo-p-dioxin and dibenzofuran (PBDD/F) emissions in China. Isotope dilution high-resolution gas chromatography high-resolution mass spectrometry for qualitat ...
DOI:
10.1016/j.ecoenv.2020.111722

13. Changes in the key aroma compounds of matsutake mushroom (Tricholoma matsutake Sing.) from Canada during pan-frying elucidated by application of the sensomics approach

Author:
Pueschel, Veronika A.; Schieberle, Peter
Source:
European food research & technology 2021 v.247 no.1 pp. 51-65
ISSN:
1438-2377
Subject:
isotope dilution technique,   etc   ; Tricholoma matsutake; evaporation; flavor; food research; mushrooms; odor compounds; odors; pan frying; solvents; stable isotopes; Canada;     Show all 12 Subjects
Abstract:
... A distillate obtained by solvent extraction and solvent-assisted flavor evaporation (SAFE) from raw, unprocessed matsutake mushrooms (Tricholoma matsutake Sing.) from Canada were analyzed by application of the aroma extraction dilution analysis (AEDA). Twenty-eight aroma-active compounds were detected in the flavor dilution (FD) factor range of 4–4096 among which (E)-methyl cinnamate (sweet, fruit ...
DOI:
10.1007/s00217-020-03606-9

14. Chiral analysis of cis-2-methyl-4-propyl-1,3-oxathiane and identification of cis-2,4,4,6-tetramethyl-1,3-oxathiane in wine

Author:
Wang, Xingchen; Capone, Dimitra L.; Roland, Aurélie; Jeffery, David W.
Source:
Food chemistry 2021 v.357 pp. 129406
ISSN:
0308-8146
Subject:
isotope dilution technique,   etc   ; acetaldehyde; assays; enantiomers; food chemistry; gas chromatography-mass spectrometry; headspace analysis; information; odor compounds; odors; optical isomerism; solid phase microextraction; stable isotopes; wines;     Show all 14 Subjects
Abstract:
... cis-2-Methyl-4-propyl-1,3-oxathiane (cis-2-MPO), arising from 3-sulfanylhexan-1-ol (3-SH) and acetaldehyde, was recently identified in wine, but the enantiomeric distribution was unknown. Such information could reveal influences on wine aroma, given the impact of chirality on odorant molecules. Herein, a stable isotope dilution assay employing headspace solid-phase microextraction with chiral gas ...
DOI:
10.1016/j.foodchem.2021.129406

15. Quantification of glyphosate and other organophosphorus compounds in human urine via ion chromatography isotope dilution tandem mass spectrometry

Author:
Schütze, Andre; Morales-Agudelo, Pilar; Vidal, Meghan; Calafat, Antonia M.; Ospina, Maria
Source:
Chemosphere 2021 v.274 pp. 129427
ISSN:
0045-6535
Subject:
isotope dilution technique,   etc   ; biomarkers; carcinogenicity; diet; glyphosate; humans; ion exchange chromatography; metabolites; moieties; phosphates; stable isotopes; standard deviation; tandem mass spectrometry; urine;     Show all 14 Subjects
Abstract:
... Organophosphorus pesticides are the most used pesticides in the United States. Most organophosphorus pesticides are composed of a phosphate (or phosphorothioate or phosphorodithioate) moiety and a variable organic group. Organophosphorus pesticides are scrutinized by regulatory bodies and agencies because of their toxicity or suspected carcinogenicity. Upon exposure, organophosphorus pesticides an ...
DOI:
10.1016/j.chemosphere.2020.129427

16. Development of isotope dilution-liquid chromatography/tandem mass spectrometry for the accurate determination of type-A trichothecenes in grains

Author:
Gab-Allah, Mohamed A.; Choi, Kihwan; Kim, Byungjoo
Source:
Food chemistry 2021 v.344 pp. 128698
ISSN:
0308-8146
Subject:
isotope dilution technique,   etc   ; accuracy; acetonitrile; chemical species; food chemistry; isotopes; liquid chromatography; measurement; solid phase extraction; tandem mass spectrometry; trichothecenes; water;     Show all 12 Subjects
Abstract:
... We report the development of a highly accurate method based on isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) for the simultaneous determination of four major type-A trichothecenes in cereal grains. Uniformly labeled [¹³C] analogues of the target analytes were used as internal standards. An expedient sample preparation procedure was established. After extraction with ...
DOI:
10.1016/j.foodchem.2020.128698

17. Determination of patulin in apple juice by amine‐functionalized solid‐phase extraction coupled with isotope dilution liquid chromatography tandem mass spectrometry

Author:
Li, Xianjiang; Ma, Wen; Zhang, Qinghe; Li, Hongmei; Liu, Huwei
Source:
Journal of the science of food and agriculture 2021 v.101 no.5 pp. 1767-1771
ISSN:
0022-5142
Subject:
isotope dilution technique,   etc   ; adsorbents; agriculture; apple juice; detection limit; laws and regulations; liquid chromatography; patulin; polymers; quality control; solid phase extraction; sugars; tandem mass spectrometry;     Show all 13 Subjects
Abstract:
... BACKGROUND: Patulin is a mycotoxin that mainly contaminates apple juice, which is a typical high sugar matrix. Many different adsorbents have been utilized to develop a sample pretreatment method to minimize the matrix interference from apple juice. RESULTS: A simple and reliable extraction method for the determination of patulin in apple juice has been developed. The sample preparation involves a ...
DOI:
10.1002/jsfa.10790

18. Cloud point extraction coupled with ultrasound-assisted back-extraction for determination of trace legacy and emerging brominated flame retardants in water using isotopic dilution high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry

Author:
Zhou, Xia; Gao, Yan; Zhang, Qinghe; Li, Xiuqin; Li, Hongmei
Source:
Talanta 2021 v.224 pp. 121713
ISSN:
0039-9140
Subject:
isotope dilution technique,   etc   ; detection limit; extraction; flame retardants; liquids; mass spectrometry; pressure; repeatability; sampling; standard deviation; temperature; ultrasonic treatment; volume; water;     Show all 14 Subjects
Abstract:
... Isotopic dilution high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry method was developed for determination of seven legacy and emerging brominated flame retardants (BFRs) in water using cloud point extraction coupled with ultrasound-assisted back-extraction. The effects of different experimental conditions on the recovery and matrix effect dur ...
DOI:
10.1016/j.talanta.2020.121713

19. New sample preparation method to analyse 15 specific and non-specific pesticide metabolites in human urine using LC-MS/MS

Author:
Fišerová, Petra Stuchlík; Kohoutek, Jiří; Degrendele, Céline; Dalvie, Mohamed Aqiel; Klánová, Jana
Source:
Journal of chromatography 2021 v.1166 pp. 122542
ISSN:
1570-0232
Subject:
isotope dilution technique,   etc   ; 2,4-D; coumaphos; creatinine; dicarboxylic acids; environmental monitoring; humans; liquid chromatography; malathion; p-nitrophenol; pesticide metabolites; solid phase extraction; spectrometers; thiophosphate; urine;     Show all 15 Subjects
Abstract:
... This study presents a novel sample preparation method for the determination of both specific and non-specific pesticide metabolites in human urine samples. The method combines a deconjugation step with QuEChERS-based method and solid-phase extraction. In total, 15 pesticide metabolites (diethyl phosphate; diethyl thiophosphate; dimethyl phosphate; diethyl thiophosphate; 2,4-dichlorophenoxyacetic a ...
DOI:
10.1016/j.jchromb.2021.122542

20. Species Interactions and Nitrogen Use during Early Intercropping of Intermediate Wheatgrass with a White Clover Service Crop

Author:
Li, Shoujiao; Jensen, Erik Steen; Liu, Nan; Zhang, Yingjun; Dimitrova Mårtensson, Linda-Maria
Source:
Agronomy 2021 v.11 no.2
ISSN:
2073-4395
Subject:
isotope dilution technique,   etc   ; Thinopyrum intermedium subsp. intermedium; Trifolium repens; agronomy; biomass; dry matter accumulation; intercropping; interspecific competition; nitrogen; nitrogen fertilizers; soil; sole cropping;     Show all 12 Subjects
Abstract:
... Perennial grain crops intercropped with legumes are expected to use nitrogen (N) resources efficiently. A pot experiment using the ¹⁵N isotope dilution method demonstrated interspecific competition and use of N from the soil and N₂ fixation in intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, IWG) and white clover (Trifolium repens L., WC) intercrops at five species-re ...
DOI:
10.3390/agronomy11020388