Although conventional gas chromatography mass spectrometry (GC/MS) provides relatively high efficiency separations, the analysis of some complex, natural-matrix samples may require the use of even higher resolution approaches. Comprehensive two-dimensional gas chromatography (GC x GC) is an emerging high-resolution technology which uses coupled GC columns to achieve separations that are not possible by conventional GC. Separations in the “first dimension” that are carried out on a long GC column are directed via a modulator to a short GC column with different selectivity (the “second dimension”), and are detected by time of flight mass spectrometry (TOF-MS). Because the entire sample is represented in the analysis, the technique is described as “comprehensive.” Efforts at NIST are being directed toward the study of issues related to quantitation by GC x GC/TOF-MS, and to the value assignment of complex matrix Standard Reference Materials. A particular emphasis is being placed on metabolomics and environmental applications.
The development of robust analytical methods remains one of the most important (and costly) parts of chemical metrology. The resolution of targeted constituents is requisite for accurate and precise measurements. High-resolution separation technologies provide several advances over conventional approaches: (1) increased capabilities for the analysis of complex samples; (2) easier and less costly method development; (3) more robust methods that remain in control even if changes over time result in de-optimization; (4) more accurate and precise metrology. The Analytical Chemistry Division has a variety of measurement efforts that involve the analysis of complex matrix samples. GC x GC/TOF-MS will provide high-resolution separations that will be used for both qualitative and quantitative analysis.
Additional Technical Details:
GC columns are being strategically chosen for use in the first and second dimensions to assess the separation capabilities of the GC x GC technique for metabolomics research and environmental applications. Three initial applications are being studied: (1) determination of amino acids (with different derivatization methods), (2) determination of cholesterol (using a traditional derivitization method), and (3) determination of PAHs.
Start Date:October 1, 2008
Lead Organizational Unit:mml
Related Programs and Projects:
Fundamental Chemical Metrology
Optimization of the Standard Additions Method Using Monte Carlo Simulation
Mercury Vapor Pressure Correlation
High-Precision Isotopic Measurements and Standards
Potential Primary Measurement Tool for the Quantification of DNA
Studies of Micro-Scale Heterogeneity of Solid Reference Materials
Improving High-Performance ICP-OES Determinations Using Exact Matching
Evaluation of Independent High-Precision Assay Procedures for a High-Purity Primary Standard Reagent
Molecular Simulation of Alkylsilane Stationary Phases in Liquid Chromatography