Using MicroMounts™ and MicroLoops™ for Small Molecule and Inorganic Crystallography

Mitegen's products are much easier to use and give less background scatter than glass fibers and other mounting tools common in small molecule crystallography. Choose the "SM" versions of our MicroMounts and MicroLoops allow small molecule data collection at large inclination angles relative to incident X-ray beam, without beam scattering by the supporting stainless steel rod.

Select a MicroMount or MicroLoop with a sample aperture size slightly smaller than the crystal size. This will help minimize background X-ray scatter.

Cut the stainless steel rod (if necessary) to a desired length using our cutters or other cutters designed for spring-temper steel. Use the millimeter scale on the label of the product box, lining up the end of the pin with the right end of the scale.

Insert the rod into a goniometer base (our B4 base is most popular for small molecule applications) using a small amount of, e.g., Dow-Corning #976V high vacuum grease or Duco Cement hold it in place. The stainless steel rod can also be inserted into a 0.7 mm mechanical pencil for easy handling during crystal mounting.

Scoop or place the crystal into the sample aperture. The crystal can be held in place using a tiny amount of, e.g., contact adhesive, applied using a small (25 gauge or smaller) tungsten or molybdenum wire. Alternatively, a small drop of ethyl cellulose dissolved in ethyl acetate can be placed on the crystal/mount and allowed to evaporate, providing a thin polymer film that holds the crystal in place.

If mounting samples from solution, please read our notes for macromolecular crystallography and mounting small crystals.

To make the ethyl cellulose/ethyl acetate mixture:

Mix 300 micrograms ethyl cellulose in 75 ml of ethyl acetate.

Slowly heat the mixture (with boiling chips) to the boiling point in a fume hood, and boil gently for 5 minutes. Let cool to room temperature. Be sure to read warnings about each component. Ethyl acetate can be dangerous at temperatures above 77 C.

Both components are available from many US suppliers.

ethyl acetate:

     J.T. Baker (1-800-582-2537)

ethyl cellulose: (Be sure to specify powder or granule form.)

     Island Group 516-746-2100

     Rotuba 908-486-1000

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