In experiments to test the stability of authentic AsA (final concentration 0.1 μM) in the presence of EDTA or CaCl2 exudation buffers less than 5% oxidation was observed in either case over 90 min (data not shown).
Due to the lack of the authentic reference material, concentrations of NVP-AUY922 glucuronide were reported as analyte/internal standard peak area ratios.
In most cases, polyphenol contents of foods before and after processing were determined by high-performance liquid chromatography (HPLC) where identities could be verified with reference to authentic standards, and concentrations could be reliably calculated from chromatographic peak areas.
Although absolute concentrations cannot be determined without generating calibration equations like those above for every NP, which would require the use of authentic standards of known concentration for all 137 appropriate compounds, the general concentration ranges for these NPs are estimated to be 1 100 nM.
Due to the lack of authentic standards and low concentration of metabolites, the current study only presents qualitative data.
The average ion abundance of [M H] m/z = 336.06 for each sample was plotted as a linear function of the concentration of authentic hmdCMP added.
A calibration curve was constructed with different concentrations of authentic l-ascorbic acid (0.020 0.12 mg/mL) as the standard.
The ratios of the peak areas of the analytes added into post-extracted blank plasma and the peak areas of pure authentic standards at equivalent concentrations were measured and defined as the matrix effect (ME).
No isotopically labeled cyclic di-GMP was available, so cyclic di-GMP in cell extracts was quantified by spiking cell extracts (stationary phase) with known concentrations of authentic cyclic di-GMP and compared against un-spiked extracts.
For calibration curves, solutions containing certain concentrations of authentic DNA bases (0.0, 2.0, 5.0, 10.0, 20.0, and 50.0 μg/mL) were subjected to HPLC-UV analysis.
Calibration was performed on a daily basis with authentic standards at multiple concentrations, and the experimental standards were diluted so that the areas of all peaks fell within the calibration range.
