Introduction to Isotope Dilution

PEth 16:0/18:1 was quantified after liquid-liquid extraction using two independent isotope dilution - liquid chromatography - tandem mass spectrometry methods.

An isotope dilution-liquid chromatography tandem mass spectrometry method (ID-LC/MS/MS) has been developed as a candidate reference method for the accurate measurement of major type B trichothecenes and conjugated deoxynivalenol mycotoxins in grain samples.

This contribution presents a new reference material, ASH-15, a flowstone that is dated here by isotope dilution (ID) thermal ionization mass spectrometry (TIMS) analysis using 37 sub-samples, 1–7  mg each.

We present a detailed map of the lithologies and structure of the Kuna Crest lobe, associated sheeted complex and satellite plutons, and their host rocks, using chemical abrasion−isotope dilution−thermal ionization mass spectrometry and laser ablation−inductively coupled plasma−mass spectrometry U-Pb zircon geochronology, element and isotope geochemistry, and Al-in-hornblende thermobarometry to conclude the following: (a) The 94.

Pseudo isotope dilution (PID) was suggested as a simple and practical approach for the correction of barium-related spectral interferences on the measurement of europium by inductively coupled plasma mass spectrometry (ICP-MS).

High-performance ion chromatography (HPIC) was used to separate the target elements from one another while sector-field inductively coupled plasma-mass spectrometry (SF-ICP-MS) was used for their determination relying on isotope dilution for calibration.

The matrix CRM developed was quantified using isotope dilution high-performance liquid chromatography coupled with tandem mass spectrometry.

In this study, we established a highly sensitive, specific, and quantitative method for the detection of the IDP homoanserine and its oxidized derivative 2-oxo-homoanserine via high-performance liquid chromatography tandem mass spectrometry coupled with a stable-isotope dilution method, and quantitatively analyzed its tissue distribution and age-related intra-brain distribution in C57BL/6J mice.

A set of 50 single-donor samples was assigned target values for concentrations of 25(OH)D2, 25(OH)D3, 3-epi-25-hydroxyvitamin D3 (3-epi-25(OH)D3), and 24R,25-dihydroxyvitamin D3 (24R,25(OH)2D3) using isotope dilution liquid chromatography – tandem mass spectrometry (ID LC-MS/MS).

The method applies QuEChERS extraction and isotope dilution gas chromatography coupled with tandem mass spectrometry (GC-MS/MS).

This paper presents an Isotope Dilution Liquid Chromatography-Mass Spectrometry (ID LC-MS) method developed for detection of melamine in powdered milk.

Furthermore, the aroma complexity of the fermentation product has been carefully identified applying a sensomic approach involving the use of gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and stable isotope dilution assay (SIDA) to identify and quantify aroma compounds.

Here we present high-precision chemical abrasion−isotope dilution−thermal ionization mass spectrometry zircon U-Pb ages for three newly discovered tuff layers interlayered with lava flows in the Kupukuziman and Kaipaizileike formations in the Keping area (Xinjiang, northwest China).

These assemblages are referable to the Playfordiaspora crenulata Palynozone interpreted as latest Permian in age on the basis of high precision Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry (CA-IDTIMS) dating of thin volcanic ash beds within and stratigraphically bracketing the unit.

Isotope dilution high-resolution gas chromatography high-resolution mass spectrometry for qualitative and quantitative analysis of PBDD/F congeners revealed that the mean PBDD/F mass concentrations were 271.

A method for the determination of 25 organochlorine pesticides (OCPs) in the atmosphere using isotope dilution high-resolution gas chromatography/high-resolution mass spectrometry (ID-HRGC/HRMS) was developed.

Here we developed an ultra-sensitive and accurate LC-MS/MS quantification method based on derivatization, isotope dilution, and solid phase extraction.

METHODS We used online solid-phase extraction coupled to isotope dilution high-performance liquid chromatography-tandem mass spectrometry after enzymatic hydrolysis of conjugates to quantify in 3038 samples the urinary concentrations of six neonicotinoid biomarkers: four parent compounds (acetamiprid, clothianidin, imidacloprid, thiacloprid) and two metabolites (N-desmethyl-acetamiprid, 5-hydroxy-imidacloprid).

In this paper, we report high-precision isotope dilution-negative-thermal ionization mass spectrometric (ID-N-TIMS) molybdenite Re-Os ages for the newly discovered, world-class Chalukou porphyry Mo deposit (reserves of 2.

Rhenium-osmium (Re-Os) dating of sulfide minerals, especially molybdenite, by isotope dilution-negative thermal ionization mass spectrometry (ID-NTIMS) yields demonstrably accurate, robust ages.

The objectives of this experiment were to evaluate and compare underivatized (UND) and precolumn derivatized (DER) methods for quantification of bovine plasma AA by isotope dilution ratio via liquid chromatography-electrospray ionization (ESI)-single quadrupole mass spectrometry.

Eight odorants predicted to contribute to Wagyu beef aroma were compared between Japanese Black cattle and Holstein cattle using a stable isotope dilution assay with GC–tandem quadrupole mass spectrometry.

Background To evaluate the impact of cold fermentation time on bagel rolls, the key aroma-active compounds in the volatile fractions obtained from three different bagel rolls through solvent assisted flavor evaporation (SAFE) were sequentially characterized by an aroma extract dilution analysis (AEDA), quantified by stable isotope dilution and analyzed by odor activity values (OAVs) respectively.

The changes in aroma-active compounds were determined by application of aroma extract dilution analysis in combination with gas chromatography-mass spectrometry/olfactometry for identification, and by stable isotope dilution assays for quantification.

In this study, a method for the accurate determination of 5-Me-THF in human plasma samples of various volumes was established using isotope dilution ultra-high performance liquid chromatography-mass spectrometry (ID-UPLC-MS).

The CDC clinical standardization program is developing a high throughput method using the gold-standard equilibrium dialysis (ED) procedure with isotope dilution ultra-high-performance liquid chromatography tandem mass spectrometry (ID-UHPLC-MS/MS).

The current study aimed: (i) to external validate total body water (TBW) and extracellular water (ECW) derived from athlete and non‐athlete predictive equations using radioisotope dilution techniques as a reference criterion in male and female athletes; (ii) in a larger sample, to determine the agreement between specific and generalized equations when estimating body fluids in male and female athletes practicing different sports.

Body mass is measured with calibrated scales, volume with underwater weighing or air‐displacement plethysmography, total body water with isotope dilution, and osseous mineral mass by dual‐energy X‐ray absorptiometry.

In this work, a stable isotope dilution ultrahigh-performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) method was developed and validated for simultaneous determination of Nε-(carboxymethyl)lysine (CML), Nε-(carboxyethyl)lysine (CEL), and acrylamide (AA) in baked and fried foods.

In this nonclinical study, we have developed a highly sensitive and selective approach to measure free and total SN-38 and its glucuronidation metabolite (SN-38G) using stable isotope dilution (SID) ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS).

Here we report U-Pb age results for mantle-derived zircon from pyroxenite xenoliths in Oahu, Hawaii, using laser ablation inductively coupled plasma mass spectrometry and isotope dilution - thermal ionization mass spectrometry.

Its effective closure temperature of 450–550 °C for the U-Pb system makes apatite an important natural medium-temperature thermochronometer that can be dated by both laser ablation inductively coupled plasma mass spectrometry (LA–ICP-MS) and isotope dilution thermal ionization mass spectrometry (ID–TIMS) techniques.

We report a liquid chromatography–isotope dilution mass spectrometry method for the simultaneous quantification of 131 intracellular bacterial metabolites of Clostridium autoethanogenum.

We present an isotope dilution mass spectrometry method (IDMS) for rapid and accurate quantification of the primary antigens, spike and nucleocapsid proteins.

The sRM was value assigned with an isotope dilution mass spectrometry-based candidate reference method calibrated using the certified pRM.

EDCs were measured using isotope dilution gas chromatography-high resolution mass spectrometry or high-performance liquid chromatography-tandem mass spectrometry, and inductively coupled plasma-mass spectrometry, respectively.

In total, 15 pesticide metabolites (diethyl phosphate; diethyl thiophosphate; dimethyl phosphate; diethyl thiophosphate; 2,4-dichlorophenoxyacetic acid; 3-phenoxybenzoic acid; 4-fluoro-3-phenoxybenzoic acid; coumaphos; diethyl dithiophosphate; malathion dicarboxylic acid; p-nitrophenol; cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid; 3,5,6-trichloro-2-pyridinol; N,N-diethyl-3-methylbenzamid and 2-isopropyl-4-methyl-6-hydroxypyrimidine) were separated using liquid chromatography coupled to a mass spectrometer and isotope dilution method for quantitation.

We analyzed the four urinary DEHP metabolites (mono-2-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP)) in 240 children aged 5–16 years, using isotope dilution GC-MS/MS.

Quantification was performed by stable isotope dilution analysis.

Quantitation of the 36 most important compounds by means of stable isotope dilution assays followed by a calculation of odor activity values on the basis of odor thresholds in corn starch revealed 2-acetyl-1-pyrroline, vanillin, the tautomers 2-acetyl-3,4,5,6-tetra-hydropyridine and 2-acetyl-1,4,5,6-tetrahydropyridine, 3-(methylthio)propanal, 2-propionyl-1-pyrroline, and methanethiol as the key aroma-active compounds.

Retinol isotope dilution (RID) was used to estimate TLR in Zambian women in the Rufunsa district; serum aliquots were selected for metabolomics based on adequate (TLR > 0.

OBJECTIVE This study assessed the efficacy of consuming VA-fortified rice, which delivered 500 µg retinol activity equivalents (RAEs)/d, on TBSs and estimated total liver VA reserves (TLRs) in Thai lactating women using the retinol isotope dilution (RID) test.

In this study, we developed a method for the traceable quantification of the peptide content using species-specific isotope dilution and ICP-MS/MS detection.

For this purpose, a method was employed for the single run speciation analysis of Cr(III) and Cr(VI) in rice samples using species-specific isotope dilution (SS-ID) and high performance liquid chromatography coupled to inductively coupled mass-spectrometry (HPLC-ICP-MS) and selective single run species complexation/derivatisation.

The nitrogen fixation contribution was estimated by 15N isotope dilution experiments.

The nitrogen fixation contribution was estimated by 15N isotope dilution experiments.

Quadruple isotope dilution (ID4) was coupled to the SD-SFDF-LPME method in order to alleviate matrix effects and promote accuracy/precision of the method.

The accuracy of method was evaluated by matrix matching and quadruple isotope dilution strategies.

Additionally, apatite grains that are present have failed to produce precise isotope dilution-thermal ionization mass spectrometer (ID-TIMS) results due to their high common lead content.

Whole-rock, feldspar and amphibole compositions were combined with zircon trace-element geochemistry and precise isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) U–Pb zircon crystallisation ages to arrive at a detailed, time-resolved record of chemical and physical changes within the voluminous, upper-crustal (∼2.

A new isotope dilution inductively coupled plasma mass spectrometry (ICPMS) method is developed to determine picomolar concentrations of titanium (Ti) in seawater.

A new Isotope Dilution (ID) method using a labelled reaction gas in ICP-DRC-MS has been established and a theoretical background for the method is given.

In this paper, we report high-precision isotope dilution-negative-thermal ionization mass spectrometric (ID-N-TIMS) molybdenite Re-Os ages for the newly discovered, world-class Chalukou porphyry Mo deposit (reserves of 2.

Chemical compositions, including high-precision isotope dilution–derived concentrations of selected highly siderophile elements (Re, Os, Ir, Pt, Se, Te), and Re-Os and Se isotope data support this hypothesis.

This report describes the development and validation of a high-throughput isotope dilution UHPLC-MS/MS method for measuring a major oxidative stress biomarker, 8-iso-prostaglandin F2α (8-isoprostane), in BAL fluid samples.

Therefore, we developed a high throughput isotope dilution LC-MS/MS method to simultaneously measure VEA and three other related tocopherols in aerosolized EVP samples.

An isotope dilution-liquid chromatography tandem mass spectrometry method (ID-LC/MS/MS) has been developed as a candidate reference method for the accurate measurement of major type B trichothecenes and conjugated deoxynivalenol mycotoxins in grain samples.

An isotope dilution method for determination of riboflavin in human plasma using LC-MS/MS has been developed and validated in this study.

We report a new 1850 ± 4 Ma (U-Pb isotope dilution–thermal ionization mass spectrometry [ID-TIMS] on baddeleyite) crystallization age for one dike and new paleomagnetic data for 34 dikes of which 8 have precise U-Pb ages.

Collectively, the two suites are better interpreted as a single magmatic event, termed the Michael- Shabogamo Gabbro (MSG), with ages ranging from 1425 to 1450 Ma, based on new U-Pb isotope dilution thermal ionization mass spectrometry baddeleyite ages of 144963, 143764 and 1435610 Ma, along with previously published ages.

METHODS Melphalan was quantified by stable-labeled isotope dilution analysis in whole blood by PS-MS/MS.

We measured the concentrations of choline and several metabolites using 1H single-voxel MRS of liver in vivo and using 2H-labeled isotope dilution MS of several choline metabolites in extracted plasma.

Herein, we propose a fast, simple, and low-cost analytical procedure for the traceable determination of Li concentration in human serum, based on the monitoring of the Li isotope dilution through the partially resolved isotope shift in its electronic transition around 670.

Herein, we propose a fast, simple, and low-cost analytical procedure for the traceable determination of Li concentration in human serum, based on the monitoring of the Li isotope dilution through the partially resolved isotope shift in its electronic transition around 670.

Zircon ages, trace element compositions, and Hf and O isotopic compositions were obtained by both laser ablation ICP-MS and secondary ionization mass spectrometry in situ techniques and chemical abrasion isotope dilution-thermal ionization mass spectrometry techniques.

These assemblages are referable to the Playfordiaspora crenulata Palynozone interpreted as latest Permian in age on the basis of high precision Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry (CA-IDTIMS) dating of thin volcanic ash beds within and stratigraphically bracketing the unit.

A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions w of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum.

99987 n(233U)/n(U)) has been prepared and characterized for use as an isotope dilution mass spectrometry spike.

Carbonates that were previously considered impossible to date using isotope dilution methods may preserve radiogenic domains that can be dated using spatially resolved laser ablation geochronology techniques.

METHODS Ten obese adult spayed female dogs were included, and their body composition was determined by the deuterium isotope dilution method.

This paper presents an Isotope Dilution Liquid Chromatography-Mass Spectrometry (ID LC-MS) method developed for detection of melamine in powdered milk.

This paper has developed a method for the determination of aflatoxin M1 in milk powder by isotope dilution liquid chromatography–tandem mass spectrometry (ID-LC-MS/MS) with immunoaffinity extraction as the pretreatment method, which was validated and determined the content of aflatoxin M1 in milk powder accurately.

Quantitation of the 36 most important compounds by means of stable isotope dilution assays followed by a calculation of odor activity values on the basis of odor thresholds in corn starch revealed 2-acetyl-1-pyrroline, vanillin, the tautomers 2-acetyl-3,4,5,6-tetra-hydropyridine and 2-acetyl-1,4,5,6-tetrahydropyridine, 3-(methylthio)propanal, 2-propionyl-1-pyrroline, and methanethiol as the key aroma-active compounds.

A multi-mycotoxin LC-MS/MS method was developed to quantify 13 free and modified Alternaria toxins in different beer types by applying a combination of stable-isotope dilution assays (SIDAs) and matrix-matched calibration.

Quantification was performed by stable isotope dilution analysis.

With the chemical purity of SENS-1 established, it was then used as the primary standard for reverse isotope dilution analysis, where the concentration of selenomethionine in SEES-1 was determined to be 1556 ± 60 μg g−1 (k = 2).

Results: The patients in the hematologic tumor group had an increase in weight, height, body mass index, waist, hip, and arm circumference, subscapular skinfold thickness, and fat mass with the isotope dilution technique during chemotherapy.

Due to potentially inconsistent recoveries, which ranged from 60 to 87%, quantification was performed using the isotope dilution technique (ID).

The matrix CRM developed was quantified using isotope dilution high-performance liquid chromatography coupled with tandem mass spectrometry.

Isotope dilution high-resolution gas chromatography high-resolution mass spectrometry for qualitative and quantitative analysis of PBDD/F congeners revealed that the mean PBDD/F mass concentrations were 271.

The uranium amount per particle was determined using optical microscopy combined with Isotope Dilution Thermal Ionisation Mass Spectrometry (ID-TIMS).

These assemblages are referable to the Playfordiaspora crenulata Palynozone interpreted as latest Permian in age on the basis of high precision Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry (CA-IDTIMS) dating of thin volcanic ash beds within and stratigraphically bracketing the unit.

In the urine of twelve L-ZSF1 and twelve O-ZFS1 rats collected at the age of 20 weeks, we measured the concentration of native and modified amino acids by reliable previously validated stable-isotope dilution gas chromatography-mass spectrometry (GC-MS) approaches.

EDCs were measured using isotope dilution gas chromatography-high resolution mass spectrometry or high-performance liquid chromatography-tandem mass spectrometry, and inductively coupled plasma-mass spectrometry, respectively.

Here, we report a stable-isotope dilution GC-MS assay that allows studying reactions of nitrite in hemolysate.

We analyzed the four urinary DEHP metabolites (mono-2-ethylhexyl phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP)) in 240 children aged 5–16 years, using isotope dilution GC-MS/MS.

In this study, a method for the accurate determination of 5-Me-THF in human plasma samples of various volumes was established using isotope dilution ultra-high performance liquid chromatography-mass spectrometry (ID-UPLC-MS).

The CDC clinical standardization program is developing a high throughput method using the gold-standard equilibrium dialysis (ED) procedure with isotope dilution ultra-high-performance liquid chromatography tandem mass spectrometry (ID-UHPLC-MS/MS).

Demographic details, AAS sub-category, time from index acute aortic syndrome event and pDES concentrations measured by stable isotope dilution LC-MS/MS were recorded at baseline.

Busulfan was extracted and detected by performing stable-isotope dilution LC–MS/MS.

15N isotopically labeled acyl-ACPs generated in high amounts are used with an isotope dilution strategy to quantify the absolute levels of each acyl group attached to the acyl carrier protein scaffold.

The accuracy of method was evaluated by matrix matching and quadruple isotope dilution strategies.

The nitrogen fixation contribution was estimated by 15N isotope dilution experiments.

A difference in substrate channeling between CRABP-1 and CRABP-2 was also supported by isotope dilution experiments.

The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry.

We evaluate here the combination of two-dimensional liquid chromatography (2D-LC) in the multiple heart cutting mode and isotope dilution tandem mass spectrometry for the direct analysis of tryptic digests of serum samples.