N e e d fast, flexible c h r o m a t o g r a p h y ?
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 always get a good "picture" with Johns-Manville Chromosorb 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 and won'tadsorbcomponentsbeing passed through. You get uniform results, optimum reproducibility, and good flow of carrier gas without excessive pressure drop. C h r o m o s o r b combines o p t i m u m surface area with high uniformity. For reduction of fines, all grades are water-screened to close tolerances.
Packing is easy. I t s 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 gas phase c h r o m a t o g r a p h y or where inertness is needed . . . Chromosorb Typical Properties Calcined diatomaceous earth aggregate. Color light pink Free Fall Density—lbs./cu. ft. (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
JOHNS-MANVILLE
For c h r o m a t o g r a p h i c studies . . . Chromosorb W Typical Properties Flux calcined diatomaceous earth aggregate. Color white Free Fall Density—lbs./cu. ft. (avg.) 15-16 Specific Gravity—true 2.30 Water Absorption—cc./gr. (avg.) 4.0-5.0 Moisture—% by weight, maximum 1.0 pH (avg.) 8-10 Surface Area (BET Method)—sq. m./gr. (avg.) 3-4
For fine n i t r a t i o n of liquids i n 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.
JOHNS-MANVILLE
JM
P R O D U C T S
Circle No. 153 on Readers' Service Card
VOL. 3 1 , NO. 6, JUNE1959
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