I have only purchased 100x PES membrane filters. I use methamphetamine through these filters and although I haven't tried nylon or PTFE, the PES filters with a .65 micron prefilter and a .22 micron secondary filter (yellow in colour), 13mm in size, works extremely well and most times it actually improves the quality of the drug immensely. It generally produces a cleaner high that is alot more speedy without losing the drugs other attributes. There was one occasion were I had some meth without the filter and it had no legs and didn't make anyone talkative. After a filtered mix, the same drug had me chatting from morning to night. There have been other occasions were I was told we were sold bad quality drugs and honestly through the filter, you couldn't tell the difference.
So you don't want the filter, for purification purposes to be any bigger than 13mm, otherwise the flowrate will be too quick and too much of the drug will be retained. so buy 13mm size filters and NOT 25mm. 13mm size filters are designed for sample sizes between 1ml and 10ml. I have studied the membrane materials that you can use and PVDF and PES seem to be the main ones you can use that you can get from this website that I get them from that is alot cheaper than the other websites. Its called Cobetter and they sell all sorts of filtration devices including most types of syringe wheel filters. As far as I know the best material to use would be regenerated cellulose which is certified for HPLC testing. The only thing I noticed about regenerated cellulose (RC) membranes is that they are extremely expensive and the have a high resistance to most chemical solvents, so if they were to work well, they would be very selective in allowing through only some chemical solvents; and they should in theory: allow through methamphetamine. I skimmed through an article on how to purify methamphetamine and it talked alot about preparing the sample for HPLC testing. So that's where I got the idea that the filters should be HPLC certified. If you search for filters on cobetter which are HPLC certified. Only a few come up. But the only ones that are hydrophilic (allows aqueous solutions through) that are available are PES, which are proven to work very well. You need the filters to be hydrophilic and NOT hydrophobic otherwise it wont pass aqueous solutions easily, nor will it filter drugs effectively. PVDF is said to work better for aqueous solutions and PES, for cell culture media but PES has a wide range of purposes. I probably wouldn't recommend PTFE because they are designed more for aggressive solvents. You want the membrane to have low protien binding, meaning that it retains less protien in the filter because methamphetamine is proteinaceous meaning that it is protein based so this is why you want it to have low protein binding. Next factor to consider is membrane wall fiber pore size (the pore size of the fibers within the membrane wall) which you want to be 5 microns which is ideal for methamphetamine and ideally you want the pore size to be consistent and you can get membranes that are certified for this too but this will make them more expensive. PVDF have a broad chemical compatibility and good for Sample filtration of biological samples and protein solutions prior to HPLC. So HPLC certified too. PVDF are suitable for aqueous solutions and sample filtration. They are available on cobetter with a dual layer .65uq to .22uq for better loading capacity and can handle a heavier push behind the solution before it clogs. Nylon is not an ideal material for membrane because it retains more protien because it has a higher protein binding and because methamphetamine is proteinaceous, you want a lower protein binding. So from the internet for syringe wheel filter membrane materials. I have found through my own research, the best to be PES or PVDF and PES have already been highly successful through many trials. Next time I buy filters, I will buy the graded PVDF filters to compare them with the graded PES ones I already have. You ideally want the filters to be certified for HPLC sample preparation and have a consistent membrane wall fiber size.
If anyone has actually tried nylon and PTFE filters and achieved positive results: I would like to hear their stories otherwise I will let you know how I go improving the quality of the drug, Methamphetamine, through PVDF filters when I get them. Both the PES and PVDF should filter out bacteria as this has more to do with the .22uq pore size than material type and I have seen from experience that this also includes cutters that are removed and produces a better hit as a result, sometimes adding another dimension to the effects of the drug. It should remove all sorts of nasty things, such as talc, non-soluble particles larger than .22uq, viruses, bacteria, cutter but they should not be re-used if you want to keep bacteria out and the only viruses they still allow through are hep c and hiv.
