Front Cover: Streamlined microfluidic analysis of phosphopeptides using stable isotope‐labeled synthetic peptides and MRM‐MS detection

2018 ◽  
Vol 39 (24) ◽  
Author(s):  
J. Deng ◽  
F. Ikenishi ◽  
N. Smith ◽  
I. M. Lazar
Keyword(s):  
Stable Isotope ◽  
Synthetic Peptides ◽  
Front Cover ◽  
Ms Detection ◽  
Microfluidic Analysis

scholarly journals Streamlined microfluidic analysis of phosphopeptides using stable isotope‐labeled synthetic peptides and MRM‐MS detection

2018 ◽  
Vol 39 (24) ◽  
pp. 3171-3184 ◽  
Author(s):  
Jingren Deng ◽  
Fumio Ikenishi ◽  
Nicole Smith ◽  
Iulia M. Lazar
Keyword(s):  
Stable Isotope ◽  
Synthetic Peptides ◽  
Ms Detection ◽  
Microfluidic Analysis

scholarly journals Evaluation of a Stable Isotope-Based Direct Quantification Method for Dicamba Analysis from Air and Water Using Single-Quadrupole LC–MS

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3649 ◽  
Author(s):  
Manoj Ghaste ◽  
Nicholas C. Hayden ◽  
Matthew J. Osterholt ◽  
Julie Young ◽  
Bryan Young ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Water Samples ◽  
Detection Method ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Sample Collection ◽  
Selected Ion Monitoring ◽  
Ms Detection ◽  
Direct Quantification

Dicamba is a moderately volatile herbicide used for post-emergent control of broadleaf weeds in corn, soybean, and a number of other crops. With increased use of dicamba due to the release of dicamba-resistant cotton and soybean varieties, growing controversy over the effects of spray drift and volatilization on non-target crops has increased the need for quantifying dicamba collected from water and air sampling. Therefore, this study was designed to evaluate stable isotope-based direct quantification of dicamba from air and water samples using single-quadrupole liquid chromatography–mass spectrometry (LC–MS). The sample preparation protocols developed in this study utilize a simple solid-phase extraction (SPE) protocol for water samples and a single-step concentration protocol for air samples. The LC–MS detection method achieves sensitive detection of dicamba based on selected ion monitoring (SIM) of precursor and fragment ions and relies on the use of an isotopically labeled internal standard (IS) (D3-dicamba), which allows for calculating recoveries and quantification using a relative response factor (RRF). Analyte recoveries of 106–128% from water and 88–124% from air were attained, with limits of detection (LODs) of 0.1 ng mL−1 and 1 ng mL−1, respectively. The LC–MS detection method does not require sample pretreatment such as ion-pairing or derivatization to achieve sensitivity. Moreover, this study reveals matrix effects associated with sorbent resin used in air sample collection and demonstrates how the use of an isotopically labeled IS with RRF-based analysis can account for ion suppression. The LC–MS method is easily transferrable and offers a robust alternative to methods relying on more expensive tandem LC–MS/MS-based options.

Front Cover: New Approaches for Absolute Quantification of Stable‐Isotope‐Labeled Peptide Standards for Targeted Proteomics Based on a UV Active Tag

PROTEOMICS ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2070081
Author(s):  
Karsten Schnatbaum ◽  
Victor Solis‐Mezarino ◽  
Daniil Pokrovsky ◽  
Frederike Schäfer ◽  
Dennis Nagl ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Absolute Quantification ◽  
Targeted Proteomics ◽  
Front Cover ◽  
New Approaches

scholarly journals Light contamination in stable isotope-labelled internal peptide standards is frequent and a potential source of false discovery and quantitation error in proteomics

2021 ◽  
Author(s):  
Mogjiborahman Salek ◽  
Jonas D Foerster ◽  
Wolf-Dieter Lehmann ◽  
Angelika B Riemer
Keyword(s):  
Mass Spectrometry ◽  
Stable Isotope ◽  
Biological Samples ◽  
Synthetic Peptides ◽  
Isotopic Enrichment ◽  
Internal Standards ◽  
False Discovery ◽  
Potential Source ◽  
Internal Peptide ◽  
Detection And Quantification

In mass spectrometry-based proteomics, heavy internal standards are used to validate target peptide detections and to calibrate peptide quantification. Here we report light contamination present in heavy labelled synthetic peptides of high isotopic enrichment. Application of such peptides as assay-internal standards potentially compromises the detection and quantification especially of low abundant cellular peptides. Therefore, it is important to adopt guidelines to prevent false-positive identifications of endogenous light peptides as well as errors in their quantification from biological samples.

scholarly journals Front Cover: Late‐Stage Hydrocarbon Conjugation and Cyclisation in Synthetic Peptides and Proteins (ChemBioChem 10/2021)

ChemBioChem ◽  
2021 ◽  
Vol 22 (10) ◽  
pp. 1686-1686
Author(s):  
Aline D. Araujo ◽  
Huy T. Nguyen ◽  
David P. Fairlie
Keyword(s):  
Late Stage ◽  
Synthetic Peptides ◽  
Front Cover
Sign in / Sign up

Export Citation Format

Share Document