An Improved Method for Visualizing TLC Plates Using Iodine Far some years now we have used s simple variation on the classic method of visualizing thin-layer chromatogiaphy (TLC) plates by letting them stand in a sealed tank containing crystals of iodine. Iadine is a popular visualizing agent because it is easv to use. inexoensive.. and eives useful results most of the time.' .. U'hilr lookhg fur n means 18, wrunlm some natural pndurts thar did not quench the fluoresctnt indw,ator in the silica rrl un prrparntivr l'I.C plates, we found that by cowring ail but a m a l l strip at the edge of the plate w i t h a pircc d'&.cs and spr~nklmgsolid iudinp un thp r q n w d itnp wp were a b k to tlnd rhp d r i ~ r r dbands and rrmove thcrn ,sacriticit,: thr v1sua117edlwrri~nof C O U I P P ~ .The disadvantage with solid iodine was that it spread pwrly, lcft m:mv dark sptlti and war ottrns~veto usroutside ofthe hood. The prublem was iulvpd by shaking rocether 0.21, g uf wdmp and 2.5 g uf 80-mrsh sil~cagel in a small jar with a scrrw-on cover.Thr mlxture 1s ~ n ~ r ~ amnk l l v and hasdiscrrnahlr ~articlrsoiiodinr but ditrr a ddv i,r so, all thr i d i n e ha.
