Introduction to Stable Isotope Dilution

Fourteen substances were quantitated by stable isotope dilution analysis (SIDA) and further two odorants via internal standard method, all of them revealed odor activity values (OAVs; ratio of concentration to odor threshold) ≥1.

The ethyl esterified peptides in sake were quantitated using stable isotope dilution analysis and additional quantitation of (pGlu)L was performed using an external standard method.

Nine odor-active constituents, which were previously detected in those woods, were quantified using stable isotope dilution analysis (SIDA).

In the present study, the pattern of dual phosphorylation of extracellular signal‐regulated kinase (ERK) is profiled on the TEY motif using stable isotope dilution (SID)‐selective reaction monitoring (SRM) mass spectrometry (MS) to elucidate the order and magnitude of endogenous ERK phosphorylation in cellular model systems.

Lastly, a quantitative TLC-FAPA-MS method using stable isotope dilution analysis was developed and applied to the quantification of caffeine in energy drinks.

Voided feces were analyzed using stable isotope dilution gas chromatography‐mass spectrometry to determine fecal concentrations of SCFAs.

A total of 10 neonics were quantified in ultratrace amounts (ng/kg) using stable isotope dilution, with calibration curves spanning 4 orders of magnitude.

Quantitation of all 28 aroma compounds by stable isotope dilution assays (SIDA) and calculation of odor activity values (OAV) confirmed 2-ACPY, 4-HDF, and phenylacetic acid as key contributors to the pretzel aroma profile.

The total body water and bone mineral content were estimated using the stable isotope dilution method and dual energy X-ray absorptiometry, respectively, at the same time points.

Compounds with FD ≥ 64 were quantitated by stable isotope dilution assays (SIDAs), and odor activity values (OAVs) were calculated.

Moreover, using the stable isotope dilution method, we showed evidence for the endogenous formation of CHH in red blood cells exposed to hydrogen peroxide.

Stable isotope dilution analysis (SIDA) and internal standard method were applied to quantitate 42 odorants, revealing 35 compounds in concentrations above their respective odor thresholds in SDTS and 29 compounds in VDTS, respectively.

Tissue-specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps with stable isotope dilution, while muscle oxygen fluxes were measured with high resolution respirometry.

Here, we present the development and validation of a sensitive method using stable isotope dilution liquid chromatography coupled with mass spectrometry for determining various folates in plasma.

Quantitation of the most odour-active compounds by means of stable isotope dilution assays, followed by calculation of odour activity values (OAV, ratio of concentration to odour threshold), revealed concentrations above the threshold level for 20 compounds in the unroasted and 24 compounds in the roasted beans.

A systematic quantitation of selected odorants using stable isotope dilution analysis (SIDA) was performed in six native cold-pressed rapeseed oils with desired retention of bioactives and desired sensorial attributes (“positive controls”, PCs), in nine native cold-pressed rapeseed oils eliciting a fusty/musty off-flavor (OFs), and in two rapeseed samples, from which two of the nine fusty/musty OFs were pressed.

In positively screened samples, we quantified paclitaxel, 3’-p-hydroxypaclitaxel, and 6α-hydroxypaclitaxel by stable isotope dilution-LC-HRMS.

The 21 odorants were quantitated by stable isotope dilution assays (SIDA), and a subsequent calculation of odor activity values (OAV; ratio of concentration to odor threshold) revealed 3-methyl-1-butanol ( malty), 2-phenylethanol ( honey-like), trans-4,5-epoxy-( E)-2-decenal ( metallic), 2,3-butanedione ( buttery), 3-methylbutanoic acid ( sweaty), ( E)-2-nonenal ( cucumber-like), 1-octen-3-one ( mushroom-like), and 3-(methylthio)-propanal ( potato-like) as the most important contributors to the overall aroma of the dumpling.

The occurrence of glucose-derived β-carboline alkaloids tangutorid E (Tan E) and tangutorid F (Tan F) as well as their dehydroxy-derivatives (DH-Tan E/F) was investigated in a broad variety of foodstuffs by LC-MS/MS-based stable isotope dilution analysis (SIDA).

In the present study, a method for quantitation of methionine, methionine sulfoxide, and methionine sulfone by a stable isotope dilution assay using HILIC-ESI-MS/MS was established.

Subsequent quantitation using stable isotope dilution assay analysis (SIDA) and calculation of odor activity value (OAV) revealed 22 compounds with OAV>1; with the highest OAV value for 3-methylbutanal with malty odor (6660), 2 methyl butanal with malty odor (4560), methional with boiled potato odor (2047), 3-hydroxy-4,5-dimethyl-2(5H)-furanone with lovage-like odor (1233), dimethyl trisulfide with cabbage odor (475), 2-phenylethanol with rosy odor (414), β-damascenone with boiled apples (200), vanillin with vanilla odor (184), 4-hydroxy-2,5-dimethyl-3(2H)-furanone with caramel odor (172) and phenylacetladehyde with honey odor (100).

Eight compounds with flavor dilution factors ≥16 were quantitated in a 16-day sample using stable isotope dilution assays.

Further, we succeeded in quantifying the peptides in the serum of pregnant women using stable isotope dilution.

By combining the improved robustness and coverage with stable isotope dilution (SID) techniques, advantages of the separate assays can now be realized in a single run, thereby improving the throughput of this type of analysis.

After DEHA was administered to four healthy volunteers (107-164 µg/kg body weight (bw)), urine samples were continuously and completely collected for 48 h and analyzed for the specific oxidized monoester metabolites mono-2-ethyl-5-hydroxyhexyl adipate (5OH-MEHA), mono-2-ethyl-5-oxohexyl adipate (5oxo-MEHA), and mono-5-carboxy-2-ethylpentyl adipate (5cx-MEPA), as well as for the non-specific hydrolysis product adipic acid (AA) using stable isotope dilution analysis.

This method, stable isotope dilution assay (SIDA), was used to accurately determine DON levels in 196 sorghum samples representing 98 different accessions.

Method development was conducted and stable isotope dilution employed, using AFB1-D3 for aflatoxins and OTA-D5 for ochratoxins.

We have modified the stable isotope dilution HPLC-ESI-MS/MS method previously described by Qu (Qu et al.

Quantification is performed by stable isotope dilution analysis, using deuterium-labeled standards of each of the three metabolites.

Therefore, 18 selected aroma compounds were determined in rice and wheat breads by stable isotope dilution assays (SIDA) to elucidate differences in the sensory characteristics, concentrations and odor activity values (OAV).

Objective: In this study, stable isotope dilution assay (SIDA) was compared with a matrix-matched calibration method for the quantification of mycotoxins in four different commercially available commodities and two reference materials.

Selected odorants, including those with FD factors ≥16, were quantitated by stable isotope dilution assays (SIDAs), and odor activity values (OAVs) were determined.

For the first time, total folate content and vitamer distribution in microalgae were analyzed by stable isotope dilution assay (SIDA) using LC-MS/MS, which has demonstrated its superiority with respect to folate quantification.

In the present study, we quantified by stable isotope dilution gas chromatography–mass spectrometry (GC–MS) the concentration of free (f) and total (t) ADMA, Arg, hArg, lysine (Lys) and the sum of citrulline (Cit) and ornithine (Orn) (6 M HCl, 20 h, 110 °C) in serum samples of apparently healthy elderly subjects (n = 27; age, 31–105 years) who were tested for Hp infection.

Two approaches were compared: a stable isotope dilution (SID) method- used as a reference and a modified SID (mSID) procedure.

This review article focuses on volatile vapor-phase quantitation methods (internal standard normalization, standard addition, stable isotope dilution assay, multiple headspace extraction) and their suitability in different applications.

Accordingly, solid-phase extraction (SPE), in combination with a stable isotope dilution assay (SIDA) and subsequent gas chromatography–mass spectrometry (GC–MS) for analysis of methyl-, ethyl-, and n-propylparaben (MeP, EtP, and n-PrP), was found to be well-suited, with recoveries ranging from 93 to 99%.

To allow a reliable quantitation of benzene, a stable isotope dilution assay using (2H3)benzene as the internal standard was developed and solid phase microextraction (SPME) was used for volatile isolation followed by GC × GC–TOFMS analysis.