Trace Level Detection of Chemical Weapons Convention Compounds by Two-Dimensional C13-NMR Spectroscopy using a Cryogenic Probehead and H1-Detection Techniques
Abstract
Two-dimensional H1-C13 heteronuclear single quantum correlation (HSQC) and fast-heteronuclear multiple quantum correlation (HMQC) pulse sequences were implemented using a cryogenic probehead for detecting Chemical Weapons Convention compounds in complex mixtures. The H1-C13 correlations of target analytes at < or = 25 micrograms/mL were easily detected in a sample where the H1 solvent signal was ~58,000 fold more intense than the analyte H1 signals. The problem of overlapping signals typically observed in conventional H1 spectroscopy was essentially eliminated, while H1 and C13 chemical shift information could be derived quickly and simultaneously from the resulting spectra. The fast-HMQC pulse sequence generated magnitude mode spectra suitable for detailed analysis in ~4.5 h, and can be used to efficiently screen a large number of samples. The HSQC pulse sequence on the other hand, required roughly twice the acquisition time to produce suitable spectra. These spectra, however, were phase sensitive, contained considerably more resolution, and proved to be superior for detecting analyte H1-C13 correlations. Use of the pulse sequences considerably improves the performance of NMR spectroscopy as a complementary technique for the screening, identification, and validation of chemical warfare agents and other small molecule analytes in complex mixtures and environmental samples.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2009
- Accession Number
- ADA507477
Entities
People
- David B. Cullinan
- Terry J. Henderson
Organizations
- Edgewood Chemical Biological Center