Nuclear magnetic resonance sample purity

Peak purity can be assessed with a higher degree of certainty only by additional analysis using a significantly different chromatographic mode. The collected sample should also be analyzed by techniques that can be sensitive to minor structural differences such as nuclear magnetic resonance (NMR) spectroscopy [29-31]. 

The experimental apparatus, as shown in Figure 11-1, was a standard molecular beam machine with a heated pulsed valve for vaporization of the non-volatile species and for supersonic cooling. Samples of 1-methyluracil, 1,3-dimethyluracil and thymine were purchased from Aldrich Co. and used without further purification. The sample 1,3-dimethylthymine was synthesized from thymine following a literature procedure [33], and its purity was checked by nuclear magnetic resonance (NMR) and infrared absorption (IR) spectroscopy. The heating temperatures varied for different samples 130°C for DMU, 150°C for MU, 180°C for DMT, and 220°C for thymine. No indication of thermal decomposition was observed at these... 

Sample Handling. Forensic Sciences Blood Analysis Explosives Systematic Drug Identification. Nuclear Magnetic Resonance Spectroscopy Techniques Nuclear Overhauser Effect. Pharmaceutical Analysis Drug Purity Determination Sample Preparation. 

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