Freeze-dried, Fourier-transform infrared spectroscopy

Figure 12 The correlation of storage stability with protein structure as determined by Fourier transform infrared spectroscopy (FTIR) apparent first-order rate constants for aggregation of freeze dried rlL-2. (O) 45°C storage. ( ) 29°C storage. (Data from [67].)...

Nuclear magnetic resonance spectroscopy ( C CP/MAS Solid State NMR) and Fourier transform infrared spectroscopy (FT-IR) were also performed for the freeze dried NOM sample. The results were both very noisy and paramagnetic compounds such as iron and manganese interfered with the - C NMR analysis. After 20 h of run time the sample showed mostly alkyl and alkyl-oxygen carbon, thus very little aromatic compounds. 

Freeze drying Drying of a wet sample along the sublimation curve of the solvent. The process avoids the direct liquid-gas transition observed in ordinary drying FTIR Fourier transform infrared spectroscopy... 

It would be most desirable to study lipid oxidation in intact food products without the extraction or sample preparation steps currently necessary (e.g., pelletization, freeze-drying). Perhaps improvements in techniques such as the Fourier transform infrared photoacoustic spectroscopy (Yang and Irudayaraj, 2000) will open such possibilities. 

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