| Precautions |
When a relatively high current or voltage is set during membrane transfer, there will be a noticeable heat - generation phenomenon, that is, the so - called Joule heating effect. This will cause the resistance of the transfer buffer to decrease, ultimately affecting the membrane - transfer efficiency, the buffering capacity of the transfer buffer, and in extreme cases of overheating, may even lead to the gel melting or adhering to the membrane. Since this product generates less heat during use, when performing membrane transfer at a constant current of 400 mA, simply using an ice box in the transfer tank for cooling is sufficient. If the entire transfer tank is placed in an ice bath for cooling simultaneously, the membrane - transfer effect will be even better. Additionally, it is advisable to pre - cool the prepared transfer buffer at 4°C or in an ice bath.
When using this product for membrane transfer, if the constant current is set at 400 mA, whether transferring 1 or 2 gels in the same transfer tank, the voltage is usually around 200 V at the beginning. During the membrane - transfer process, as the temperature of the transfer buffer gradually increases and the resistance decreases, the voltage is usually between 100 - 150 V at the end. The membrane - transfer efficiency is related to the electric field strength (represented by E) and the charge carried by the protein, and the electric field strength is mainly related to the voltage and the distance between the electrodes, that is, E = U/d.
Due to the differences in the brands and models of power supplies used for membrane transfer, on the one hand, there are significant differences in the maximum current, and on the other hand, the power also varies greatly. Generally, power supplies with higher power are relatively more expensive and more suitable for membrane transfer. For example, the maximum power of the Bio - Rad Powerpac Basic Power Supply is 75 W. When the constant current is set at 400 mA, once the voltage exceeds 187 V, it will exceed the maximum power of the power supply and trigger overload protection. Some power supplies will automatically reduce the voltage or current, while others will report an error and stop the membrane - transfer process. In case the membrane - transfer stops, it is necessary to lower the current or voltage, or choose a power supply with greater power.
During membrane transfer, the temperature of the transfer buffer, parameters of the gel (such as quantity, thickness, ion concentration, acrylamide concentration, etc.), the thickness of the filter paper, the number of transfer tanks used simultaneously, the ion concentration of the transfer buffer, the volume of the transfer buffer, and the number of times the transfer buffer has been used may all affect the current and voltage. If 2 or more transfer tanks need to be used simultaneously, it is recommended to use a high - current and high - power power supply, or set a lower current or voltage for a relatively long - time membrane transfer.
If an error occurs and the membrane - transfer stops, it is necessary to check whether there is voltage or current overload according to the situation, or other abnormal conditions such as too much or too little transfer buffer, short - circuit or open - circuit in the transfer tank.
This product is only for scientific research by professionals. It must not be used for clinical diagnosis or treatment, food, or pharmaceuticals, and should not be stored in ordinary residential areas.
For your safety and health, please wear a lab coat and disposable gloves when operating. |
Data sheet for OM750015