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Table 6 FTIR measurement advice for three-dimensional polymeric objects

From: Non-invasive identification of polymers in cultural heritage collections: evaluation, optimisation and application of portable FTIR (ATR and external reflectance) spectroscopy to three-dimensional polymer-based objects

ATR clampedATR handheldER
To make good contact with the ATR crystala, ensure flat or convex surface selected
Use a card barrier to project object surface from being marked by the clamp
To make good contact with the ATR crystala, ensure:
– Consistent pressure applied to object (standing upright over FTIR may assist)
– Sample does not shift (may be useful for another person to operate the computer)
If unable to apply consistent pressure, select lower number of co-added scans
Select appropriate aperture size:
– Small for irregular or curved surfaces (present convex surface)
– Medium or large if surface is flat
Support the object with blocks
Use the camera to ensure object is in focus
Do not shift or bump during measurement
If required, increase co-added scans to improve spectral quality
  1. aAn initial pre-scan allows the operator to evaluate whether good contact has been achieved resulting in a good quality spectrum