I am working on synthesizing and then purifying peptides using the SPPS system. After purification of the peptide, the peptide powder is obtained using a freeze dryer. When measuring the powder, the static electricity is so severe that it is impossible to measure properly. After freeze drying, ask for advice on how to reduce the static electricity of the powder. The buffers used for purification are 0.1% TFA in water and ACN.
The charges on your peptides are part of that challenge, it's a very difficult one to change. The simple solutions are good earthing, including for the personnel in the lab, but including all the lab furniture and equipment, care in choice of lab tools like spatula - some plastics make things worse, and use of anti static generator in critical areas, like at weighing station.
Kind regards,
Rob
Dear Lee Hwa Hyen , as Mr. Darrington said, statically charged products are really problematic in case of their realization, especially in your case to hold a lyophilization small amount product.
One good solution may be photoionization treatment of the final products, but for this you may need special equipment in your hand.
https://www.hamamatsu.com/resources/pdf/etd/Photoionizer_TAPP1084E.pdf
Water (2-5%) can dissipate the tribo-charge. Other approaches use grounding the equipment or apply an opposite charge to the surface of the equipment. You need to determine the charge on your particles. During lyophilization you end up with amorphous material; therefore, you need a two step drying process to avoid tribo-charging.
Dear Dr. Andrei Blasko , thank you for your suggestion. It is interesting to know about two step drying process. Is this a redissolving and redrying process to reduce the charging?
No, the two step process does not involve redissolving the solid. After drying to a certain level of water content, there is a second drying with different lyophilization parameters to remove the remaining water. After the first stage, the water content helps dissipate the static electricity. Start around 5% water content and optimize it for your purpose. You can also do an experiment with the tribo-charged powder subjecting it to different %RH values to find out the minimum water content that eliminates the charge.
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