Buck M500 - Sample Preparation Techniques for Infra-Red using the Buck M-500 Spectrometer; Sample Preparation Techniques

Sample Preparation Techniques for Infra-Red using the Buck M-500 Spectrometer
Basic and Advanced Operation
1. For Water-free, SOLID ORGANIC powder samples =
 Dissolve ~100 mg of material in 1 – 2 ml of solvent (Methanol, Ethanol, Methylene Chloride,
Chloroform, Acetone, Hexane or Freon-113).
 Using an eye-dropper, place a drop or two on a clean salt (NaCl) plate and let the solvent
evaporate, leaving a CAST FILM of the sample.
 Make a CAST FILM of the material on the PLC-11M Prism Cell (after collecting a
Background scan on the empty, clean crystal).
 Scan the sample and process normally.
 Place ~100 mg of material in an agate mortar & pestle, add several drops of NUJOL (light
mineral oil) and mix well for a minute or two.
 Put a drop of this “dispersion on a clean salt plate and spread thin with a second salt plate to
create a thin MULL of the sample.
 Subtract (or ignore) the hydrocarbon bands around 1480 & 1375 cm
-1
.
2. For Water-free, LIQUID ORGANIC solutions, gels or pastes =
 Place a drop or two of material on a clean salt plate and spread thin with another salt plate to
make a SMEAR FILM of the sample.
 Dilute the materials with a compatible solvent and make a CAST FILM on a clean salt plate
using a drop or 2 of the solution.
 Using the PLC-11M Prism Cell, take a Background scan first, then deposit the sample on the
crystal.
 Take a scan of the sample and process normally.
3. For Solid POWDERS that are not soluble in any solvent (inorganics) =
 Put ~10 – 50 mg of the finely powdered, DRY sample in an agate mortar & pestle, add ~250
mg of dry Potassium Bromide (KBr) and grind well together for 1 – 2 minutes.
 Place ~100 mg of the mixture in a KBr DIE and press into a pellet using a Carver Press for the
13mm die or a pair of wrenches for the 7 mm mini-Press to form a clear pellet. Vacuum is
recommended.
 Place ~100 mg of material in an agate mortar & pestle, add several drops of NUJOL (light
mineral oil) and mix well for a minute or two.
 Put a drop of this “dispersion on a clean salt plate and spread thin with a second salt plate to
create a thin MULL of the sample.
 Subtract (or ignore) the hydrocarbon bands around 1480 & 1375 cm
-1
.
 Using the NUJOL MULL preparation, place the material on the PLC-11M Prism Cell and scan
normally.
4. For SYNTHETIC POLYMER & PLASTIC materials = (Pellets, films, irregular shapes)
 If the material is soluble in hot SOLVENT, prepare a CAST FILM of the sample by dissolving
small cuttings or shavings of the Polymer in a test tube or small beaker of warm solvent (use a
water bath on a hotplate). Swirl to keep material moving and speed dissolution.
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