A Gas Chromatography‐Molecular Rotational Resonance Spectroscopy Based System of Singular Specificity

2019 ◽  
Vol 59 (1) ◽  
pp. 192-196 ◽  
Author(s):  
Daniel W. Armstrong ◽  
Mohsen Talebi ◽  
Nimisha Thakur ◽  
M. Farooq Wahab ◽  
Alexander V. Mikhonin ◽  
...  
Author(s):  
M. Farooq Wahab ◽  
Saba Aslani ◽  
Alexander V. Mikhonin ◽  
Justin L. Neill ◽  
Daniel W. Armstrong

2019 ◽  
Vol 132 (1) ◽  
pp. 198-202 ◽  
Author(s):  
Daniel W. Armstrong ◽  
Mohsen Talebi ◽  
Nimisha Thakur ◽  
M. Farooq Wahab ◽  
Alexander V. Mikhonin ◽  
...  

2015 ◽  
Author(s):  
Brent J. Harris ◽  
Robin L. Pulliam ◽  
Justin L. Neill ◽  
Matt T. Muckle ◽  
Roger Reynolds ◽  
...  

1969 ◽  
Vol 23 (6) ◽  
pp. 575-581 ◽  
Author(s):  
Stuart Armstrong

A number of recent review articles have summarized the application of Molecular Rotational Resonance (MRR) spectroscopy to the area of molecular structure determinations and described how these applications have applied to chemistry. This article will briefly review this established area of MRR spectroscopy and describe two developments that offer the promise of expanding the applicability of MRR spectroscopy. The first development was the observation that some large molecules (by MRR standards) give a series of relatively intense, equally spaced bands that can be quickly recorded and assigned. The other development has been in the theory, procedures, and instrumentation required for accurate intensity measurements. These two developments, examples of each, and the implication of each for use by chemists, as well as molecular structure determinations, will be discussed. Spectrometers that are being used for studies in this established area and the two newer areas will be described in the Appendix.


Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3651
Author(s):  
Natalia Drabińska ◽  
Piotr Młynarz ◽  
Ben de Lacy Costello ◽  
Peter Jones ◽  
Karolina Mielko ◽  
...  

Urinary volatile compounds (VCs) have been recently assessed for disease diagnoses. They belong to very diverse chemical classes, and they are characterized by different volatilities, polarities and concentrations, complicating their analysis via a single analytical procedure. There remains a need for better, lower-cost methods for VC biomarker discovery. Thus, there is a strong need for alternative methods, enabling the detection of a broader range of VCs. Therefore, the main aim of this study was to optimize a simple and reliable liquid–liquid extraction (LLE) procedure for the analysis of VCs in urine using gas chromatography-mass spectrometry (GC-MS), in order to obtain the maximum number of responses. Extraction parameters such as pH, type of solvent and ionic strength were optimized. Moreover, the same extracts were analyzed using Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), to evaluate the applicability of a single urine extraction for multiplatform purposes. After the evaluation of experimental conditions, an LLE protocol using 2 mL of urine in the presence of 2 mL of 1 M sulfuric acid and sodium sulphate extracted with dichloromethane was found to be optimal. The optimized method was validated with the external standards and was found to be precise and linear, and allowed for detection of >400 peaks in a single run present in at least 50% of six samples—considerably more than the number of peaks detected by solid-phase microextracton fiber pre-concentration-GC-MS (328 ± 6 vs. 234 ± 4). 1H-NMR spectroscopy of the polar and non-polar extracts extended the range to >40 more (mainly low volatility compounds) metabolites (non-destructively), the majority of which were different from GC-MS. The more peaks detectable, the greater the opportunity of assessing a fingerprint of several compounds to aid biomarker discovery. In summary, we have successfully demonstrated the potential of LLE as a cheap and simple alternative for the analysis of VCs in urine, and for the first time the applicability of a single urine solvent extraction procedure for detecting a wide range of analytes using both GC-MS and 1H-NMR analysis to enhance putative biomarker detection. The proposed method will simplify the transport between laboratories and storage of samples, as compared to intact urine samples.


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