SPE Cartridge - Classification and recommendation

Classification 

According to principle of reaction, SPE is divided into the following three categories.

  1. Normal-phase extraction- Adsorbents used in normal phase extraction is polar. 
  2. Reversed-phase extraction- The sorbent and the target analytes by reversed-phase extraction is usually the non-polar or weak polar, relying mainly on non-polar and non-polar interactions, is a fan of Edward force or dispersion force.
  3. Ion exchange extraction- is relying on the interaction between target analytes and sorbent.

 

Selection

Select proper sorbent according to the difference between target analytes and disruptors such as polar, molecular weight and pKa, etc.

Sample Properity Sample class Suggesting Cartridge
Dissolve in Organic Reversed Phase Sorbent (e.g. methanol) CN, C18/18A, PSA, HLB
  Normal Phase Sorbent/Bonding (e.g. methanol/water) NH2, Diol, PSACarb-GCB-NH2 Carb-GCB/PSA 
  Normal Phose Sorbent (e.g. hexane) Silica, Florisil, Alumina, SLE
Dissolve in Water Cation SCX, C8/SCX, MCXPRS
  Anion SAX, C8/SAX, MAX
  Reversed Phase Sorbent (e.g. non-ion type)

C18/18A, C8, MCX, HLB

For reverse phase, normal phase and adsorption type SPE cartridges, the quantity of target analytes to SPE sorbent ratio is generally not more than 5%. For ion exchange SPE cartridges, need to consider the ion exchange capacity.  Provide the conventional ion exchange capacity of Starlab is about 0.3meq/g, the following table for SPE cartridges capacity parameters

 

Specification

Maximum Sample Load

Volume

Minimum Elution volume

50-100mg

2.5mg-5mg

1mL

100-200μL

100-200mg

5mg-10mg

3mL

200-500μL

200mg-1g

10mg-50mg

6mL

500μL-6mL

500mg-2g

25mg-100mg

12mL

3mL-10mL

 

Merlin Scientific SPE Cartridges are made of medical grade PP and forming in one time. Frits are made of UHMW-PE.