How To Select A Thin-Film Sample Support Material

As a guide, the adjacent chart relates % Transmittance through a thin-film substance vs. analyte-line energy, KeV, and Wavelength, in Angstrom units.

  • Select the analyte-line of interest in either KeV or Angstrom units
  • At the point of extrapolated intersection of each curve, read the % Transmittance. The greater the % Transmittance value the lower the absorption will be. This may be translated into other factors such as lower elemental detection limits and shorter integration times.
  • Select the thin-film substance with the highest % Transmittance value.
  • Consider the Degradation Resistanceassignments to the thin film sample support substance for the sample types to be analyzed.

Degradation Resistance Of Thin-film Substances

CHEMICAL MYLAR or HOSTAPHAN POLY- CARBONATE Etnom-S POLY- PROPYLENE POLY- IMIDE PROLENE ULTRA- POLYESTER
Acid, dilute or weak G G G E N G G
Acids, conc. G G G E N E G
Alcohols, aliphatic N G G E G E N
Aldehydes U F F E E E U
Alkalies, conc. N N G E E E N
Esters N N F G G G N
Ethers F N F N U N F
Hydrocarbon, aliphatic G N E G E G G
Hydrocarbon, aromatic N N E N E N N
Hydrocarbon, halogenated F N F N F N F
Ketones N N G G G G N
Oxidizing agents F N F F N F F

E=Excellent, G=Good, F=Fair, N=Not recommended, U=Unknown

Shaded columns represent thin-film window materials determined “Unsuitable for analyzing sulfur in diesel fuel, gasoline and other petroleum products containing aromatic hydrocarbons,” ASTM D-4294-03 and ASTM D-6445-99 (2004), in addition to other testing procedures.

IMPORTANT: The degradation resistance of thin-films contained in the above illustration is provided as a matter of information purposes only and is not intended to preclude actual testing and suitability of use and applications. The responsibility of acceptance and safety resides totally with the user.

 
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