红外谱的样品制备-液体和固体

Sample Preparation for IR Spectra - Liquids & Solids

Bio-Rad's laboratories have prepared and analyzed thousands of samples by means of infrared spectroscopy. These samples range from commercial products like polymer beads and liquid surfactants to high purity organic compounds suitable for their standards collection. A wide variety of techniques have been developed by spectroscopists and spectral technicians in order to  obtain  high-quality  infrared  spectra  from  these  diverse materials.   The   purpose   of   this   Application   Note   is   to communicate   Bio-Rad’s   knowledge   of   infrared   sample preparation  to  you.  In  this  Application  Note,  selection  of technique based on physical characteristics of the sample will be discussed.

The  information  desired  from  a  spectrum  largely  determines how  the  compound  is  to  be  prepared  for  examination.    A
compound in the crystalline state generally yields a spectrum which has more absorption bands than the spectrum of the same compound when examined in the liquid state or in solvent solution.   The  absorption  bands  in  the  spectrum  of  a  solid compound,  examined  in  the  crystalline  state,  or  a  liquid compound, examined in the pure concentrated form (neat), are found, usually, at lower frequencies than the absorption bands in the spectrum of the same compound when it is examined in the vapor state or in solvent solution.  The degree of absorption band  shifts  depends  upon  the  presence  or  absence  of intermolecular and intramolecular forces.