I did thin layer chromatography to identify different types of fructan-type carbohydrates using butanol, acetic acid, isopropanol and water as the eluent (8:4:7:3, respectively). I let the first plate to run for 1.5 hours until the plate lanes got wet, and the second plate was run for 5 hours, after which I dried the film at room temperature for 2 hours. The plates were developed by spraying with a solution of 2 g diphenylamine, 2 ml of aniline dissolved in 82 ml of acetone and 15 ml of phosphoric acid at 100 °C for 10 min. However, the solute standard bands appear as poorly defined big spots that overlap among them. Can an expert advice on how I can improve my method to get well-defined chromatographic TLC bands?