for faster sharper separations. Here are four new products from the same silicic acid stream that has produced our Silicic Acid AR 100 mesh . . . the sorbent so often specified in chromatographic literature.

For the fast flow you want in large columns, there are two new SilicAR® CC sorbents in the coarser particle size (100-200 mesh). For maximum resolution in small columns, you'll want to try the two finer sizes (200-325 mesh).

Try all four. SilicAR products are so uniform that you can scope a separation, using SilicAR TLC sorbents on a thin layer plate, and get equivalent Rf values with SilicAR CC sorbents in small and large columns. These new sorbents offer you dependable Mallinckrodt quality, including tight control of organic contaminants.

Naturally, we'll continue to offer our popular Silicic Acid AR 100 mesh. But try these new classified SilicARs in your columns, too. Order from your Mallinckrodt distributor. For product data, write Department JW, Mallinckrodt Chemical Works, St. Louis, Mo. 63160.

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MALLINCKRODT CHEMICAL WORKS St . Louis · New York · Los A n g e l e s

Four new Mallinckrodt silicic acid sorbents...

CLASSIFIED

14 C & Ε Ν