کیسه دیالیز 14-12 کیلو دالتن با عرض 29mm

Properties

They show good chemical resistance against numerous
solvents, e.g.:
• Alcohols
• Esters
• Ketones
• Hydrocarbons
• Halogenated hydrocarbons
• Formic acid, acetic acid, diluted strong acids (e.g. 5% HCl)
• Dimethylsulfoxide, Pyridine
• 30% hydrogen peroxyde
• Silicon oil

They are not ressistant against strong acids and strong alkalis.

The tubings are stable between pH 5 – 9 and can be stored for long term in this range,
provided microbial degradation is prevented (see below). Dialysis (1 – 2 days) can
even be performed in the pH range of 2 – 12.
The tubings can be sterilized by autoclave. Once moistened, shey should not be
allowed to dry out unless reglycerinated. Tubings containing aqueous solutions can be
frozen.
All dialysis tubings made on the basis of cellulose are sensitive against Cellulase and
Cellulase producing microorganisms, especially when moistened. Therefore they have
to be stored refrigerated in aqueous media supplemented with 0.05% Na-azide or
other anti-microbial substances.
VISKING and SERVAPOR dialysis tubings have a molecular weight cutt-off (MWCO)
of 12000 – 14000, that means: proteins of this size are excluded from the membrane
at about 90% and do not penetrate through the pores. Beside the molecular weight,
the three-dimensional form, the charge and the state of hydration are important factors
which influence the penetration of a protein through the membrane. To be sure that
proteins do not diffuse through the membrane into the outer medium, one should not select a MWCO of the tubing which is closely below the molecular weight of the
protein.

Adsorption of protein is below 1 ng/g dry weight of the tubing.

Handling

To avoid contamination (e.g. with nucleases), tubings should only be touched with
gloves.

The tubings are delivered dry. They are treated with glycerol as humectant to prevent
them from drying out.

Due to the manufacturing process, they contain traces of heavy
metals (<50 ppm) and sulfur compounds (<0.3%).

For most biochemical applications,
it is suggested to remove these compounds by boiling and washing.

Several methods

have been described in the literature, e.g.:
1) Boiling successively (each time 15 minutes) in 5% Na2CO3, 50 mM EDTA pH 8,
and dist. water; between each step, the tubings have to be rinsed with dist. water

2) Boiling 30 minutes in 10 mM EDTA pH 7.5. Storage at 4° C in 1 mM EDTA pH 7.5

3) Heating to 70° – 80° C for 2 hours in heavy metal free water with occasional gentle
stirring.

The water is decanted and this procedure is repeated 3 more times.

The tubings are stored in heavy metal free water or in water with Na-azide

It is advisable to prepare a larger stock in one of these ways and to store it in the
refrigerator.

Before use, tubings have to be thoroughly washed with dist. water.
The samples are filled with a pipette into the tubings – closed at the lower end with a
clamp.

Closing by knots is not recommended, as it may damage the membrane and
result in loss of material during dialysis.
As the volume of the protein solution will increase during the dialysis process due to
penetration of water, the tubing should be filled only by 2/3.
For dialysis, the tubing, closed on both ends, is placed into a sufficiently large vessel
filled with buffer and stirred on a magnetic stirrer. Depending on the concentration
gradient and the requirements of the following procedures, we recommend 1 – 3 buffer
exchanges.