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Ion Exchange Media

DOWEX® Ion Exchange Resins

 

DOWEX® resins are made of spherical particles. The benefit for the user is a highly efficient exchange process, due to optimal flow-through kinetics because of the round (spherical) particles.

 

We offer a broad range of DOWEX® ion exchangers (anion and cation) featuring small particle sizes and narrow particle size distributions (50 - 100 mesh, 100 - 200 mesh, 200 - 400 mesh). In addition, analytical grade qualities of DOWEX® resins are available. These products are processed from original DOWEX® (»practical grades«) resins, following a proprietory procedure developed by us.

DOWEX® 1 - anion exchangers of type I, strongly basic:  
A series of gel ion exchangers based on styrene-DVB-copolymerisates of type I. Refers to U.S. Food Additive Regulations, Ref. 1.21.1148

 

Supplied form of all DOWEX® anionic resins:
pract. grade = Cl- form
analytical grade = Cl- form

Maximum working temperature for all DOWEX® anion resins listed:
100 °C for Cl- form
60 °C for OH- form

For other counter ions please inquire for special bulk production.

DOWEX® 50 W - cation exchangers, strongly acidic:
Spherical beads, sulfonated polystyrene/ DVB matrix.

Supplied form of all DOWEX® 50 W resins:
pract. = H+ form
analytical grade = Na+ form

Maximum working temperature for all DOWEX® cation resins listed:
120 °C for Na+ form
120 °C for H+ form

 

For other counter ions please inquire for special bulk production.
DOWEX® is a trademark of Dow Chemical Comp., Michigan, USA.

DOWEX® Ion Exchange Resins

SERDOLIT ® Ion Exchange Resins

Analytical Grade Qualities for the Laboratory

Ion exchangers are produced for technical purposes (practical grade). In this stage they contain a considerable amount of impurities which must be carefully removed for making them suitable for (bio)chemical purposes. In addition, smaller and better defined particle sizes are desirable. The SERDOLIT® resins have been purified with particular care to meet these requirements.

SERDOLIT ® Ion Exchange Resins

SERDOLIT ® Polymeric Adsorbent Resins

Whereas with ion exchangers (mainly) charged molecules can be adsorbed and/or separated, neutral adsorbent resins (Polymeric ADsorbents: SERDOLIT® PAD Resins) can be used for the extraction and in some cases even for separation of neutral, basic and acidic substances. This adsorption process often is performed with compounds which are dissolved in water or in a solution which does not contain too much of an organic solvent that might prohibit the interaction (van der Waals forces, hydrophobic, hydrogen bridges) between adsorbent and adsorbate.

We offer two types of SERDOLIT® PAD Resins: polar and apolar. The unpolar types (SERDOLIT® PAD I, II, III) are copolymerisates of polystyrene and DVB, whereas the polar is a polymerized methacrylic acid ester (SERDOLIT® PAD IV).

Apolar resins (PAD I - III) bind organics from water, polar SERDOLIT® PAD IV even from organic solvents. Unwanted substances (impurities, salts) are eluted with water, the enriched compound(s) with water mixable organic solvents. Their eluotropic forces are known from chromatographic experience. Acidic molecules are best eluted with basic eluents, basic molecules under acidic conditions.

SERDOLIT ® Polymeric Adsorbent Resins

SERDOLIT ® Chelating Resins

SERVACEL® Cellulose Ion Exchangers

Cellulose ion exchangers have a very loose hydrophilic network (no pores) with well separated charged groups. Ionic macro(bio)molecules are adsorbed to only a few sites which can be desorbed selectively under extremely mild conditions with high recoveries. pH stability is excellent between 3 and 12. Storage of DEAE-cellulose in 2 M NaOH for 4 months at 50 °C does not change capacity for proteins. In order to provide greater stability and pressure resistance, the cellulose matrix can be produced in »regenerated« microcrystalline form. Here the particles are granular and the amorphous (fibrous) part of the cellulose fibers is removed. For additional stabilization the fibers are crosslinked.
SERVACEL® CM 52 and DEAE 52 are microcrystalline and thus allow a more dense packing: a superior resolution can be obtained compared with fibrous material. In addition, they are supplied in pre-swollen form to facilitate handling: they are ready-to-use after equilibration with the selected buffer system. They do not require the time consuming "pre-cycling" procedure (washing with acid resp. alkali) which is necessary with cellulose ion exchangers supplied as dry powder.

CM-Cellulose - Cation exchangers (acidic type):
Cellulose is derivatized with CarboxyMethylchloride. The resulting weakly acidic high capacity exchanger can be used for neutral and basic proteins, peptides, lipids. 

DEAE-Cellulose - Anion exchangers (basic types):

DiEthylAminoEthyl-groups are covalently bound to the cellulose hydroxylic groups. This anion exchanger can be applied for the chromatography of proteins with neutral or
acidic isoelectric points (IP), which can easily be determined by isoelectric focusing electrophoresis (IEF). Serum components, enzymes, peptides, polysaccharides, RNA-types, viruses, lipids and ribosomes have been separated. DEAE cellulose is suitable for purification of nucleic acids.

SERVACEL® Cellulose Ion Exchangers


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