Need fast, flexible chromatography?
Chromosorb, inert column-packing aggregate, is a specially treated grade of J-M Celite*, the diatomaceous silica that was used in earliest gas chromatography studies.
You a l w a y s get a g o o d "picture" with J o h n s - M a n v i l l e C h r o m o s o r b A s an aggregate in gas-liquid partition chromatography, J - M Chromosorb® gives high partitioning effect with maximum number of theoretical plates. Good resolution is obtained because it is chemically inert a n d won't adsorb components being passed through. You get uniform results, optimum reproducibility, and good flow of carrier gas without excessive pressure drop. Chromosorb combines o p t i m u m surface area with high uniformity. For reduction of fines, all grades are water-screened t o close tolerances.
Packing is easy. Its physical stability and non-adsorption let you re-use the same column packing again and again. For further information, contact the dealer nearest you. *Celite is Johns-Manville's registered trade mark for its diatomaceous silica products.
For chromatographic studies .a Chromosorb W Typical Properties Flux calcined diatomaceous earth aggregate. Color Free Fall Density—lbs./cu. f t . (avg.) Specific Gravity—true Water Absorption—cc./gr. (avg.) Moisture—% by weight, maximum pH (avg.) Surface Area (BET Method)—sq. m./gr. (avg.)
For gas phase c h r o m a t o g r a p h y or w h e r e inertness is needed . . . Chromosorb Typical Properties Calcined diatomaceous earth aggregate. Color light pink Free Fall Density— lbs./cu. f t . (avg.) 20-23 Specific Gravity—true 2.15 Water Absorption—cc./gr. (avg.) 2.4 Moisture—% by weight, maximum 1.0 pH (avg.) 6-7 Surface Area—sq. m./gm. (avg.) 3-5
white 15-16 2.30 4.0-5.0 1.0 8-10 3-4
For fine filtration of liquids in laboratory application...Celite Analytical Filter Aid Quality diatomite, calcined at high temperatures and acid-washed to remove organic and inorganic impurities. Filters out all types of precipitates, including the difficult-to-handle gelatinous and semi-colloidal materials, and produces brilliantly clear filtrates at high flow rates.
J O H N S MANVILLE
JOHNS-MANVILLE
JM P R O D U C T S
Circle No. 163 on Readers' Service Card
VOL. 33, NO. 7, JUNE 1961
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