Circular Chromatography of Inks Circular chromatography provides a very convenient and rapid method of demonstrating the principles of paper chromatography. The use of Petri dishes makes it possible for every student to carry out his own experiment at very low cost. The filter paper is placed on a Petri dish. A small piece of rolled filter paper about 2 em long is inserted through a small hole in the center of a circular piece of filter paper to make contact between the solvent and the paper. The use of dyes or inks permits the student to visualize the actual process of separation. A very inexpensive and convenient sourceof dyesis theink from the fiber-tip color marker pens avdablefromallstationery shops. These come in a large variety of assorted colors and can be transferred directly to the circular paper by drawing a line and repeating if necessary. No mixing, solution, or extraction is required. Chromatography is carried out on Whatman No. 1 paper with propanol:ammonia. (25%):water 8:2:2. Separation is very rapid; the black color resolving into six clearly defined zones and the browns into three components. With radially slatted paper it is possible to chromatograph five different samples at the same time. ALFREDS. C. WAN OF SINGAPORE UNIVERSITY 3 SEPOYLINES,SINGAPORE
Volume 49, Number
5, May 1972
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335
