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Dialysis Tubing





Micro dialyzer, Dialysis tubing, Wet type Membrane and  Dialysis Accessories

Micro Dialyzer

Dialysis tubing

Wet type Membrane

Dialysis accessories


Instructions for Dialysis Tubing


1. Calculate length of tubing needed by referencing vol/cm  on side of box. Allow at least 10% additional length to allow for expansion/contraction of sample. Also allow an additional 2-4cm on either end for tubing clamps.

2. Soak tubing in distilled water for 20minutes, and rinse thoroughly in clean distilled water.

3. Clamp one end of tubing, and inject sample into the open end. Clamp the other end of the tubing, and immerse the filled tube in dialysis buffer solution.

4. When dialysis is complete, remove tube from buffer solution, release one clamp, and remove sample.


Sensitive Assay Membrane Pre-treatment


If trace amounts of sulfur or heavy metals will interfere with your procedure, the membrane should be prepared as described below;

1. Wearing gloves, cut the dialysis membrane into the desired length and soak in distilled water for 15 minutes.

2. Heat the pre-cut membrane for 30 minutes, while stirring, to 80 C in a large volume of 10 mM sodium bicarbonate.

3. Transfer the membranes into a 10 mM Na2EDTA solution and soak for 30 minutes.

4. Replace solution with distilled water and stir for 30 minutes at 80 C.

5. Allow membrane to cool down, and store in a refrigerator in a 0.05% sodium azide solution, or a 0.10% sodium benzoate solution. Alternatively, a 20-50% ethanol solution may be used. Tubing must always remain submersed.

6. Before use, wash tubing inside and out with distilled water and condition in dialysis buffer (if necessary, tubing may be sterilized).

7. Secure clamp on one end of membrane. Buffer or water should be placed inside the bag to ensure integrity of the seal. Check integrity of the tubing and clamps.

8. Pour out test solution and load sample (For concentrated salt samples, leave space in the tubing to allow for net flow of water into the sample and to prevent tubing from bursting.)

9. Immerse dialysis tubing in beaker or flask containing a large volume (usually 100 to 1000-fold that of the sample) of the desired buffer and dialyze for several hours at the desired temperature with gentle stirring. NOTE: Low-molecular weight salts and buffers (e.g.,TrisCl and KPO>4) equilibrate within 3 hours with stirring. Equilibration times for viscous samples will be longer.

10. Change the dialysis buffer as necessary. Usually two dialysis buffer changes are sufficient. When CsCl is removed from equilibrium density gradient-banded DNA, two equilibrations against a 1000-fold volume excess of buffer will decrease CsCl concentration 106-fold, to a still-significant 5 M, and it may be necessary to change buffer a third time.

11. Remove dialysis tubing from buffer, remove clamp from one end, and remove sample with a pipet.


Dialysis Membrane


Dialysis membrane is regenerated cellulose tubing prepared by the viscose process from cotton linters, one of the purest naturally occurring cellulose sources. Dialysis membrane contains water, glycerol as a humectant, and small quantities of sulfur compounds, primarily as polysulfides (approximately  0.1%). The sulfides normally need not be considered unless spectral measurements of retentate or dialysate are required. Both the glycerol and sulfides may be removed by proper washing.

Dialysis membrane rolls are over wrapped in bags of polyethylene film in order to conserve moisture. The membrane will lose some of its flexibility and possibly pinhole during handling if allowed to lose moisture to the air. In order to avoid this possibility, it is recommended that unused tubing be rewrapped in the polyethylene bag or other air-tight moisture proof container, and stored in a cool location.

Dialysis membrane tubing can be used for laboratory dialysis and ultrafiltration. Normal molecular weight cut-off is generally reported by investigators to be 12,000 to 14,000. However, molecular weight is not the only factor in molecular transfer. The shape and size of the molecule is important. Various buffer solutions should be tried because the charge of the molecule can be altered by the pH of the media. Also, tension in two directions will increase pore size. Once thoroughly wetted, the membrane should not be allowed to dry out as the subsequent shrinkage will decrease the pore size. Wetted membrane should be stored in water containing either benzoic acid or formaldehyde.

Films-packaging division technical service purification treatment for dialysis membrane
The materials in the dialysis tubing other than cellulose (cotton linters) which are present in more than trace amounts are glycerin and sulfur compounds. The glycerin can be removed by washing the tubing in running water for 3-4 hours. Removal of sulfur compounds may be accomplished by treating the tubing with sodium sulfide solution (0.3%) at 80. For 1 minute, wash with hot water(60)for 2 minutes, followed by acidification with sulfide acid (0.2%), and washing with hot water to remove the acid.


Technical Information


Level of contaminants:
- Sulfur compounds: less than 0.3%
- Heavy metals(atomic number greater than 36): less than 50ppm

pH stability range: 5 to 9

Chemical Compatibility
- Cellulose has good compatibility with many salts such as CaCl2, (NH4 )2SO4 and aqueous organic solvents commonly used in molecular biology/enzymology such as: isopropanol, ethanol and acetone.

Temperature Registance
- Dialysis Tubing can be boiled or sterilized by autoclave but should not be allowed to dry out unless reglycerinated. Tubings that contain aqueous solutions can be frozen.

Microbial Resistance
- Dialysis Tubings are sensitive to cellulose activty particularly when they are humidified. Growth of cellulolytic micro-organisms can be prevented by keeping the tubings in water containing benzoate, benzoic acid, formaldehyde or pentachlorophenol.

Protein Adsorption
- Protein adsorption of Dialysis Tubing is less than 1 nanograms/gram of dry Dialysis Tubing.

Enzymology: desalting / buffer changes / trace inhibitor removal / enzyme immobilization
Molecular biology: buffer changes

- Boil this tubing in water before use in order to remove contaminants. This does not modify the molecular weight cut-off. Use clips to close the tubing.
- Allow stirring to increase dialysis efficiency.
- Test different pH buffers for dialysis as the shape and the charge influence osmotic separations
- Use within 36 hours after soaking otherwise an antimicrobial will be required.
- Touch with hands.
- Use strong alkalis. Use solutions containing active cellulose.
- Tie the tubing. This can modify the molecular cut-off weight near the tie.


Chemical Resisitance Chart

Good Chemical Resisitance



Acetic acid





Hydrochloric acid(diluted 5%)

Ammonium hydroxide(diluted)

Hydrogen peroxide(30%)

Amyl acetate

Isopropyl alcohol

Amyl alcohol



Lactic acid

Benzyl alcohol

Methyl alcohol(98%)

Boric acid

Methyl chloride

Butyl acetate

Nitric acid(diluted 5%)

Butyl alcohol


Carbon tetrachloride


Chloracetic acid

Perchloric acid(25%)






Phosphoric acid(25%)


Potassium hydroxide(med conc 25%)

Ethyl acetate


Ethyl alcohol(95%)

Silicone oil

Ethylene glycol

Sulfuric acid(diluted 5%)



Formic acid(25%)





Fair Chemical Resistance

Ammonium hydroxide(med conc)

Hydrofluoric acid(25%)

Dimethyl formamide

Sodium hydroxide(diluted 5%)


Sodium hydroxide(med conc 25%)

Ethylene oxide

Sulfuric acid(med conc 25%)


Not Recommended

Chromic acid


Hydrochloric acid(med conc 25%)

Sodium hydroxide(conc 50%)

Iodine solutions

Trichloroacetic acid(25%)



Not a guarantee of chemical compatibility. Test under your own conditions.



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