Solvent Purification

Definition of solvent purification

Solvent purification is to remove the unwanted particles or impurities in the solvents or reagents by distillation, recrystallization or filtration. Solvent filtration is one of solvent purification techniques that is commonly used in pre-treatment of precise analysis like HPLC.

Most common grades for reagents & solvents

Organic solvents are widely used in many laboratory experiments in different purity grading. Below listed the most common grades.

• Guarantee Reagent, GR
• Reagent Grade, RG
• Analar Reagent, AR<
• American Chemical Society, ACS<
• United States Pharmacopoeia, USP
• Analysis
• Chromatography (HPLC, GC)

Solvent purification is essential for several analysis including mobile phase in HPLC (high performance liquid chromatograph) and LC-MS-MS (liquid chromatography-tandem mass spectrometry) to prevent impurities to effect experiment results or production rate.Such purification are often executed with vacuum filtration.

Solvent filtration process

Filtration is a technique used either to remove solid impurities from an organic solution by isolation the solids on the membranes. The membranes should be selected according to sample characteristics, removal rate, and filtration time.

Solvent filtration can be There are 2 common filtration methods, gravity filtration and vacuum filtration. Vacuum filtration uses pressure differences to accelerate filtration thus is generally much faster than gravity filtration.

Solvent filtration apparatus

A solvent filtration kit usually includes a chemical-resistant vacuum pump, a safety trap, a receiver flask and a set of filter holder.

A. Chemical resistant vacuum pump

Most solvent that require purification are organic solvents, acids and alkaline, thus considering safety of analysts and resistance of the pumps, chemical-resistant pumps are recommended.

All wetted parts including the air chamber, manifolds, and diaphragms of Rocker chemical-resistant pumps are made of high-resistance materials.
Rocker Chemker chemical-resistant vacuum pump–
Made of PTFE, provides highest resistance for corrosive chemicals.
Rocker C chemical-resistant vacuum pump –
All wetted parts are coated with PTFE, provides moderate resistance to lighter corrosive chemicals including alcohols and alkanes.

B. Receiver flask and filter holder

Borosilicate glass is the recommended material of receiver flask and filter holders used for solvent filtration in order to prevent damages caused by organic solvents and corrosive chemicals. Materials of the membrane support can be either fritted glass or stainless steel based on requirements.

Rocker VF Filtration Kits with benefits including:
– High temperature and chemical resistant borosilicate glass material
– Membrane support material selection: Fritted glass or stainless steel.
– Innovative spill-proof base: VF3、VF6、VF7

Solvent purification applications

• Mobile phase purification for HPLC、LC/MS/MS analysis.
  for example, Acetonitrile, methanol, and tetrahydrofuran.

References:

The Seven Most Common Grades for Chemicals and Reagents | Lab Manager
Purity and Grading (advtechind.com)
Difference Between Filtration and Purification