Rockland and other manufacturers often supply antibodies in buffers that contain sodium azide. While preservatives like azide are generally warranted in that they extend the shelf life of an antibody and protect the antibody against contaminating growth, they can prevent the immediate use of the antibody in a limited number of specialized assays. For example, sodium azide can interfere with assays involving cell culture. Sodium azide will also inhibit the enzyme horseradish peroxidase if the antibody is not diluted before use. Rockland never adds sodium azide to peroxidase conjugated antibodies.
Fortunately sodium azide can be easily removed from the buffer by dialysis. When doing this, care should be taken not to dilute the antibody solution too much without adding protective protein.
Dialysis can be performed either with dialysis tubing for large amounts or via centrifugation for small samples (AMICON and other companies make several very convenient devices for this purpose).
Note: Most methods will result in some loss of protein during transfer by adherence to surfaces.
Note: Azide can also be removed using gel filtration column based methods. For example, Sephadex G25 column system will effectively remove the azide.
Rockland Immunochemicals Inc.Limerick, PA 19468E-mail: email@example.comPhone: 800.656.7625