Chromatographic Alumina



Our selection includes Aluminas for:

Open Column Chromatography

Activity Super I Standard Activity I Activity II-III Alumina R Alumina for Dioxin Analysis

Pressure Driven Chromatography

MPLC Flash Chromatography

Alumina for TLC

Alumina for TLC

Sorbent Technologies offers a complete selection of aluminum oxide (alumina) products for column chromatography. All of these products are standardized according to Brockmann methods to ensure quality and reproducibility. Aluminas are ideal for natural product extraction, purification & decolorization, heavy metal removal, cleanup, and more.

We offer the best selection of standardized aluminas with defined activities, pH values (acid, base, neutral), and particle distributions (MPLC, Flash, Gravity). All of our aluminas are manufactured using GMP standards ensuring the highest performance and lot-to-lot reproducibility with no scale-up limitations.

Our selection includes Aluminas for:

  • Standard Chromatographic Techniques: Flash Chromatography, Classic Column Chromatography, MPLC, HPLC, TLC, and DCC.
  • Special Techniques: Removal of Peroxides from Solvents, Purification of Solvents for UV-Spectroscopy, Natural Product Purification and Decolorization, Heavy Metals Removal, Clean-up, Dioxin analysis, and Technique of Isotopes.
  • Custom Aluminas: Modifiable porosities, surface area, and particle distributions, Colloidals. Inquire.

Determination of Activity using the Brockmann and Schodder Test

The Brockmann and Schodder test is a simple and reliable method to determine the activity of adsorbents. A standardized volume of pairs of test dyes dissolved in a standard solvent is applied to a standardized column. After chromatographic development, the activity is shown by the way the test dyes are separated or not separated.

The following dye mixtures are used:

I Azobenzene (AB) and p-Methoxyazobenzene (MAB)
II p-Methoxyazobenzene (MAB) and Sudan yellow (SG)
III Sudan yellow (SG) and Sudan red (SR)
IV Sudan red (SR) and p-Aminoazobenzene (AAB)
V p-Aminoazobenzene (AAB) and p-Hydroxyazobenzene (HAB)

20 mg of each of the two dyes of an individual pair is weighed into 50 ml of the solvent.

A mixture of one part of pure benzene and four parts of pure petroleum ether (bp 50 - 70°C) (v/v) is used as solvent for the test dyes and as eluent for the chromatographic development.

10 ml of the appropriate test dye solution is carefully applied to the top of a 15 mm diameter column, filled to exactly 50 mm in height with the adsorbent to be tested. Then the column will be eluted with 20 ml of the eluent. The activity grades can be determined according to the diagram.

It has been suggested that a modification to the Brockmann and Schodder method be made in that using columns of 100 - 150 mm length be used instead of exactly 50 mm high adsorbent beds. On these columns no elution occurs. To determine the activity grade, the migration distance of the test dye in front is measured. The activity grade is then given by the number of the pair of test dyes. In addition with the distance, in mm from top of the column to the front of the foremost migrated dye.

In the example, test dye solution #I is used and azobenzene migrates 45 mm. The activity grade of the adsorbent is I/45 mm.

AluminapH Approx.ActivityLOI Approx.Particle Dist.Water Soluble Matter Approx.Bulk Density Approx.Surface Area Approx.
Super I-Acidic4.5Super I1.3%50-200µm0.1%0.8g/mL200m2/g
Super I-Neutral7.5Super I1%50-200µm0.1%0.8g/mL200m2/g
Super I-Basic10Super I1%50-200µm0.1%0.8g/mL200m2/g
Standard Act. I-Acidic4.5Act I1.7%50-200µm0.1%0.8g/mL150m2/g
Standard Act. I-Neutral7.5Act I1.7%50-200µm0.1%0.8g/mL150m2/g
Standard Act. I-Basic10Act I1.7%50-200µm0.1%0.8g/mL150m2/g
Act. II-III10Act II-III-50-200µm-0.8g/mL-
Alumina N for Flash Chromatography7.4--32-63µm0.2%0.8g/mL200m2/g
Alumina B-Super I for Dioxin Analysis10-0.7%50-200µm0.1%0.8g/mL200m2/g
Alumina R4.3--50-200µm-0.8g/mL-

Deactivation of Alumina:

Deactivation allows the chromatographer the flexibility and freedom to deactivate alumina to the precise activity level required for their specific application. Alumina may be deactivated by the addition of polar media, perferabley water, but also alcohols such as glycol or glycerol.

Sorbent Technologies' standardized aluminas are based on a deactivation scale (see chart). Alumina Super I is starndardized to such a high degree that all three surface types of aluminas, (acid, basic, neutral) show an identical initial activity, and when deactivated with equal amounts of deactivator (e.g., water), they reach the same lower activity status. The percent of water addition is based upon weight/weight relationships. Activity level is according to Brockmann/Schodder.

Deactivation Procedure:

  1. Weigh a known quantity of alumina and place into a tightly sealed vessel.
  2. Add the required amount of water (by weight or volume.)
  3. Shake the mixture in the closed vessel until all lumps disappear.
  4. Allow the mixture to cool (preferably overnight.)
  5. The container should remain tightly closed to retain activity level and can be stored for later use.
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