This paper presents and proves an algorithm to calculate the isotopic composition of individual (nominal) isotopic peaks. From this information one can calculate the accurate masses of isotopic peaks. This opens the way to use accurate mass measurements to determine chemical compositions of compounds using non-mono-isotopic peaks. The algorithm is computationally efficient and rigorously correct in the absence of roundoff error. Highly effective error correction strategies are described to detect and correct computational errors arising in practical calculations. Results from theoretical calculations of isotopic masses for a krypton inclusion complex agreed well with experimental measurements.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jasms.2003.08.011 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Microscale Spatiotemporal Variation of Reactive Oxygen Species in the Charosphere: Underlying Formation Mechanism and Their Role in CO Emission.
Environ Sci Technol
January 2025
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China.
Charosphere, a highly active zone between biochar and surrounding soil, is widely present in agricultural and wildfire-affected soils, yet whether reactive oxygen species (ROS) are produced within the charosphere remains unclear. Herein, the production and spatiotemporal evolution of charosphere ROS were explored. In situ ROS capture visualized a gradual decrease in ROS production with increasing distance from the biochar/soil interface.
View Article and Find Full Text PDFSelected Ion Extraction of Peptides with Heavy Isotopes and Hydrogen Loss Reduces the Type II Error in Plasma Proteomics.
ACS Omega
January 2025
Department of Chemistry and Biology, Faculty of Science, Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
Naturally occurring peptides display a wide mass distribution after ionization due to the presence of heavy isotopes of C, H, N, O, and S and hydrogen loss. There is a crucial need for sensitive methods that collect as much information as possible about all plasma peptide forms. Statistical analysis of the delta mass distribution of peptide precursors from MS/MS spectra that were matched to 63,077 peptide sequences by X!TANDEM revealed Gaussian peaks representing heavy isotopes and hydrogen loss at integer delta mass values of -3, -2, -1, 0, +1, +2, +3, +4, and +5 Da.
View Article and Find Full Text PDFUnveiling the role of saltmarshes as coastal potassium sinks: A perspective from porewater-derived potassium exchange.
Sci Total Environ
February 2025
Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China. Electronic address:
Saltmarshes serve as repositories for various metal species, primarily due to vegetation removal and mineralization processes. However, the significance of potassium (K), one of the three major nutrients (nitrogen, phosphorus, and K) essential for plant growth, has often been overlooked, particularly in the context of saltmarshes where the mechanisms of K transport via porewater exchange remain poorly understood. To address this knowledge gap, we conducted field observations and laboratory analysis, and developed a Rn mass balance model to quantify K fluxes via porewater exchange under physical, biological, and anthropogenic drivers.
View Article and Find Full Text PDFA Novel Liquid Chromatography-Tandem Mass Spectrometry Method to Quantify Tryptophan and Its Major Metabolites in Serum to Support Biomarker Studies in Patients with Cancer Undergoing Immunotherapy.
Molecules
December 2024
Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806 Poznań, Poland.
Tryptophan (TRP) is an essential amino acid crucial for the production of many bioactive compounds. Disturbances in TRP metabolism have been revealed in various diseases, many of which are closely related to the immune system. In recent years, we have focused on finding blood-based biomarkers of successful immunotherapy in cancer.
View Article and Find Full Text PDFSeasonal agricultural activities and monsoon shifts drive fluctuations in nitrogen levels in eutrophic coastal waters: A case study of Xiangshan Bay, China.
Mar Pollut Bull
January 2025
Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China.
Xiangshan Bay, one of China's most eutrophic semi-enclosed bays, was studied to examine the seasonal distributions of salinity, temperature, nutrients, and nitrate isotopes (δN and δO) to elucidate seasonal variations in nitrate sources and the key factors driving nitrogen level fluctuations. Based on nitrate δN (6.1-8.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!