bicarb test for coke purity
Sorry about the mindboggling. I wasn't actually suggesting using post reaction pH as measurement of purity. It seems like far too much work, although there is some merit to the idea....anyway I digress again - (slaps face and reminds self these 2-3am mornings will end post exam week when normal sleeping patterns return)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is probably the best you can hope to do without specialized stuff. To do better would require a bunch of different solvents, phys info on coke and some good lab technique. However, in the hands of an experienced person, this techniques can be done in the time it takes to make a good coffee (well OK then, if you had to grind the beans by hand!!
First establish there is no amphetamine by testing it with Marquis. If there is, it will react the same as coke and add to the final weight.
Weigh 1 gram of speed free coke using scales with a resolution no less than 0.01 resolution. Ideally these should be 0.001 or better. Anyway, the commonly seen 0.1g gram scales are not suitable or you'll only get a purity factor + - 10% (e.g. 60-69.9% + or -1%). The more accurate the measurement, of course the more meaningful the result will be.
Next is to liberate the free base using sodium bicarbonate
Mix ~1 part bicarbonate to 3 parts coke. Put in a small glass vial and add ~5-10 ml of warm water. Heat in a water bath (pot on the stove). It will start to fizz, but keep heating until fizzing stops and all is dissolved. Jiggle it to help. What doesn't dissolve is not something you want anyway. If something is left, and just in case the amount of water is too low, add a few extra mls of water and rewarm, but don't overdo it.
Let it cool and small rocks (sometimes a single large one will crystallize out of solution. Wait until it is completely cooled and tip onto a paper towel and dry.
**Take these rocks and dissolve in a small amount of zippo lighter fluid. Filter and keep the fluid. Leave in the air to evaporate and the rocks will remain.
Weigh the rocks with the same accuracy of scale. Even if the coke was 99.999999999999% pure, it will now weigh less. This is normal. You have just taken off ~11% of the weight by removing the HCl part.
For arguments sake, lets say the freebase coke now weighs 0.65g
Multiply this by 1.12 to give the original weight of cocaine HCl as 0.72.8g. This means the coke was roughly 72.8% pure
To get your coke back to the sniffable salt, dissolve in zippo, stir while adding HCl drop-wise until crystals cease to appear. It's good idea to brush up on some basic crystallization techniques before attempting this.
Summary:
Weigh Coke
Add bicarb
Heat slowly not to boiling
Cool when fizzing ceases (put your ear to it and listen closely)
Dry rocks on paper towel
Dissolve in zippo, then filter and evap zippo**
Reweigh
Percentage purity = weight of freebase x 1.12 x 100%
Re- acidify if required
** This step can be omitted, or others included to remove a greater selection of possible contaminants.