The wheel filter is composed of two parts, housing, and membrane, which can be made of different materials. Usually, housing of PTFE syringe filter is polypropylene pp with stable properties and resistant to various solvents or nylon polyamide.What we call a water system/organic system should be classified according to the material of the filter membrane, which is suitable for filtering aqueous solutions (for life sciences) and organic solutions (for chemistry). The organic system is able to filter the aqueous solution well, but the water system may be dissolved by the organic solvent, as it is not suitable for the organic system filtration.
First, use a needle tube with a luer lock syringe filter to repeatedly suck distilled water, then ultrasound for about 20 minutes, then soak in distilled water for more than 5 hours, take it out, and dry at about 40 degrees. Don't bake the gasket, just let it dry naturally.
A. Rinse it with running water ten times repeatedly, and dry (After that, we have to dry it. We also use the gasket to dry. The discoloration has little effect. The oven temperature is usually set to 56 degrees because EDAT is often dissolved).
B. Soak in 1% hydrochloric acid overnight (at least 6h or more).
C. Rinse it with running water ten times and wash it with distilled water twice, then install the filter membrane under high pressure or dry for later use.
The cap of HEPA syringe filter should not be soaked in acid liquid but should be soaked in NaOH for 6-12 hours, or boiled for 20 minutes. Two filter membranes should be installed before packaging. When installing the filter membranes, pay attention to the light side up (concave upwards), then Loosen the screw slightly, put it in an aluminum box, in a pressure cooker sterilize it for 30min, and dry it for later use. Note that the screw should be tightened immediately when taking it out of the clean bench.
Now, we know the clean method of the wheel filter, but how we disinfection the wheel filter?
Before high pressure, soak the filter membrane in three-distilled water for at least half an hour. In addition, do not overtighten the filter membrane when installing it. The filter membrane has front and back sides, with the light side facing down and the rough side facing up, which saves effort when filtering. It is practical immediately after high pressure. The filter should not be high pressure twice. The filter membrane is generally placed in two layers. I think this is more secure.
The filter membrane is generally placed in two layers. The upper filter membrane is 0.4 microns, the lower one is 0.22 microns, and both layers are 0.22 microns. After soaking for 10-20 minutes, put it into the filter (note that the side must not leak). After installation, wrap the filter with a cloth and then sterilize it. Note that the filter membrane should be perpendicular to the ground so that the membrane will not be broken even if the pressure is high.
Wheel filter should be soaked in distilled water for more than 3 hours or overnight (the purpose of soaking is to prevent the filter membrane from rupturing), and then put on the filter screen with the smooth side facing up. When the wheel filter is screwed, it is only necessary to screw on and airtight. Lift up and wrap the liquid outlet with sulfuric acid paper. Then wrap the filter in kraft paper. The filter should be tightened when in use, but pay attention to uniform force.(1) First soak in dilute hydrochloric acid for about one hour.
Note that if the wheel filter cannot be used up once, it cannot be sterilized a second time to prevent damage to the filter membrane.