Further attractive products to complete your chromatography laboratory can be found on our Chromatography page! The template results in 39 spotting positions. Application and Evaluation Guide for TLC plates biostep ® (DESAGA) This template can be used with TLC plates up to 200 x 200 mm. It has 19 markings with 10 mm spacing. Holes are provided for marking the starting line and the standard separation distance of 100 mm. The good hand rest permits spotting, writing and line ruling with minimum effort required. The R f -values can be read-off directly on the template. The marked circular areas ranging from 3 to 200 mm 2 permit immediate comparison of spot sizes without further aids.