Carbon Adsorbents: Physical Characteristics and Selection Guide

The following information is gathered to assist chemists and method developers in locating the proper specialty carbon adsorbent for their use. Additional assistance can be obtained by contacting our Technical Service group at techservice@sial.com.

• Physical Characteristics of Our Specialty Adsorbents – easy-to-use chart that shows the approximate surface area, pore volume, pore diameter, and free fall density for each of our specialty carbon adsorbents
• Carbon Adsorbent Cross-Reference – handy table to find replacements for many adsorbents, including some that are discontinued
• Carbon Adsorbent Selection Based on Analyte Size – bed order suggestions for multi-bed air monitoring tubes
• A Tool for Selecting an Adsorbent for Thermal Desorption Applications – Technical Report with detailed adsorption/desorption characteristics of fifteen of our specialty carbon adsorbents, plus nine other adsorbents

Physical Characteristics of our Specialty Carbon Adsorbents

To view the approximate surface area, pore volume, pore diameter, micropore diameter, and free fall density for each of our specialty carbon adsorbents, simply click the graphic below. Also indicated is the type of adsorbent (CMS, SGPC, GCB, etc.), the shape (spherical or granular), and whether it is scalable. Included are all our Carboxen^®, Carbosieve^®, Graphsphere™, Carbotrap^®, and Carbopack™ adsorbents. Additional assistance can be obtained by contacting our Technical Service group.

Adsorbent Cross-Reference Guide

Use this easy-to-use cross-reference table to find our recommendations for non-Supelco adsorbents, including some that are discontinued.

Adsorbent	Supelco Recommendation
Ambersorb 347	Carboxen 564
Ambersorb 563	Carboxen 563
Ambersorb 572	Carboxen 572
Anasorb CMS	Carboxen 564, Carboxen 1000, Carbosieve S-III
Anasorb CSC	Coconut charcoal
Anasorb GCB1	Carbotrap B, Carbopack B
Anasorb GCB2	Carbotrap C, Carbopack C
Anasorb 708	Chromosorb 1081
Anasorb 727	Amberlite XAD-4
Anasorb 747	Carboxen 564, Carboxen 1000, Carbosieve S-III
CarboBlack B	Carbotrap B, Carbopack B
CarboBlack C	Carbotrap C, Carbopack C
Carbograph 1	Carbotrap B, Carbopack B
Carbograph 2	Carbotrap C, Carbopack C
Carbograph 3	Carbotrap F, Carbopack F
Carbograph 4	Carbopack Z
Carbograph 5	Carbotrap X, Carbopack X
Carbosphere	Carboxen 1000
Graphpac-GC	Carbotrap B, Carbopack B
Purosieve	Carboxen 1000
Spherocarb	Carboxen 1000
Tenax GC	Tenax TA1
1 Supelco offers this adsorbent, but is not the manufacturer.

Carbon Adsorbent Selection Based on Analyte Size

To assist with the selection of our specialty carbon adsorbents, this table below lists some general guidelines based on analyte size. For multi-bed tubes, use the weaker adsorbent in front of the stronger adsorbent to protect it (this will keep analytes from adsorbing on a bed too strong, resulting in poor analyte release during desorption). For example, use Carbotrap C in front of Carbotrap B.

Relative Analyte Size1	Adsorptive Strength	Recommended Adsorbents (listed highest to lowest surface area)
C20+	Weakest to  Strongest	Carbotrap F, Carbopack F
C12-C20		Carbotrap C, Carbopack C
C9-C14		Carbotrap Y, Carbopack Y
C5-C12		Graphsphere 2027, Graphsphere 2029, Carbotrap B, Carbopack B, Graphsphere 2016, Graphsphere 2017
C3-C9		Carbotrap X, Carbopack X, Carbopack Z
C2-C5		Carboxen 1012, Carboxen 1034, Carboxen 1000, Carboxen 1008, Carboxen 1026, Carbosieve G, Carboxen 1005, Carboxen 572, Carbosieve S-II, Carboxen 1003, Carbosieve S-III, Carboxen 1032, Carboxen 1030, Carboxen 1006, Carboxen 1018, Carboxen 1010, Carboxen 1021, Carboxen 563, Carboxen 1001, Carboxen 569, Carboxen 1033, Carboxen 564
1 Analyte size relative to n-alkanes. Consider all atoms, not just carbon. For example, even though 1,2-dichloroethane is a C2, the two chlorine atoms give it a relative size between C4 and C5.

A Tool for Selecting an Adsorbent for Thermal Desorption Applications

Detailed adsorption/desorption characteristics of fifteen of our specialty carbons plus nine other adsorbents, depicted in twenty-four easy-to-follow color-coded tables, are shown in A Tool for Selecting an Adsorbent for Thermal Desorption Applications (T402025 HTA). To download your no-charge copy of this Technical Report, simply click the graphic of the report cover.