Separation of Plant Growth Regulating Substances on Silica Gel Columns.

The preparation of the silica gel is similar to the method of Bulen, et al (2) for organic acid chromatography. Silicic acid (Mallinckrodt's 100 mesh analytical reagent) is prepared, generally in one pound batches. by repeatedly washing it in distille(d water, and decanting the fine particles that do not settle out of suspension after an arbitrarily chosen period of 15 minutes. After the silicic acid (silica gel) is free of very fine particles that greatly impede solvent flow through the column, it is (Iried to constant weight at 100° C. A glass column 1.4 cm inside diameter and 30 cm long, Nvith a 250 ml solvent reservoir on one end and stopcock on the oth1er, is used to support the silica gel be(l. A smiiall plug of fine glass wool at the bottom of the column prevents the silica gel from entering the stopcock. An 8.0 g sanmple of the dried silica gel is hydrated with 5.0 ml of 0.5 M formic acid. This hydrated sample is suspended in a small amount of the 0.2 % butyl alcohol eluting solvent (petroleum ether: n-hutyl alcolhol saturated wvith 0.5 M formic acid-99.8: 0.2), poured into the column, and packed with air pressure applied to the top of the column. This results in a column of silica gel approximately 13 cm long. The sample to be analyzed is placed on top of the column in one of three ways: I. The finely ground tissue sample is mixed with 0.5 g of silica gel which lhas previously been hydrated Nith 0.4 ml of 0.5 MXT