Interpretation of Polystyrene Standard

• 1). Acquire an infrared spectrum of the polystyrene reference film standard on the FTIR that is to be calibrated. This is done by simply placing the film in the beam path of the instrument and using the "scan" command. Depending on the instrument and methodology used, a background or "blank" scan may be acquired first and subtracted from the standard scan.
  
  
• 2). Have the FTIR software locate the major absorption peaks on the resulting PS spectrum and list the peak positions in reciprocal centimeters overlaid on the spectrum or in a separate document.
  
  
• 3). Examine the position of the peaks in the PS standard spectra. The spectra should have well-defined absorption peaks at the following approximate wave numbers: 3060, 2850, 1944, 1601, 1583, 1154 and 1028 cm^-1. The exact positions expected for these peaks will be detailed in the calibration certificate accompanying the PS standard.
  
  
• 4). Ensure that the absorption peaks in the PS standard spectrum are within the confidence intervals given for each peak in the standard calibration certificate. For example, if the certificate states that the 1944 cm^-1 peak should appear at 1944 +/- 0.6 cm ^-1, ensure that the spectrum has a peak in this range. If all peaks in the spectrum appear in the appropriate range, the FTIR instrument may be considered properly calibrated with respect to wavelength accuracy.