Question regarding TLC plates for dye identification

["Susan Heald" <healds@xxxxxxxxxxxxxx>]

Hi there,
We are working on a project and are primarily interested in identifying insect red dyes. Apparently, Schleicher and Schuell, the company whose polyamide TLC plates Dr. Schweppe recommended for identifying natural dyes, is no longer making or distributing this type of TLC plate.   We did find polyamide 6 TLC plates on a polyester support made by Macherey-Nagel and distributed by Alltech Associates Inc.  When we opened the box, we found that the polyamide coating was flaking off around the edges. In fact, the coating was so fragile, it was nearly impossible to cut the plates. There was poor separation and the coating developed craqueleur during drying. We have also seen old Macherey-Nagel plates that have a craqueleur. 

Has anyone experienced this problems with polyamide coated plates? Does anyone have alternatives to the Macherey-Nagel plates?

Also - we are having difficulty finding a supplier for Uranyl Acetate. We have looked at the following companies: Fisher, Alltech, Acros, Thomas, and Cole-Parmer. Does anyone know where we could find it or have suggestions for an alternative developing chemical?

Susan Heald, Textile Conservator
Dominique Cocuzza, Mellon Fellow in Textile Conservation
National Museum of the American Indian
Cultural Resources Center
4220 Silver Hill Road
Suitland, MD 20746
(301)238-6624 ext 6317
healds@xxxxxxxxxxxxxx