Supposedly its ridiculously difficult to remove the levamisole, from what I have read but Im sure a lot of us would be interested to find out. Someone would have to determine if levamisole was in their coke to start with, and then test it again after its purified. If anyone wants to test, the method doesnt look too complicated:
Step 1. Set up 2 test vials (we use disposable spectrophotometer cuvettes—the only requirement is that they’re clear and can hold 3.5 mL or more). The first vial is for testing your sample, the second vial is a control for comparison.
Step 2. Add a small (about 20 mg) sample of powder- or crack-cocaine to the bottom of the first vial (the vial with the sample), but not the second (the control vial). If the sample is crack, you must dissolve it with a few drops of 50 percent (w/v) citric acid. The addition of citric acid is optional for powder cocaine. It will not affect the test either way.
Step 3. Add 2.25 mL of reaction buffer to each tube. The reaction buffer should be made before starting and consists of 1M diethanolamine and 0.5mM MgCl2 adjusted to pH 9.8 with HCl. We typically make this by the liter. It can be stored at room temperature for several months in glass bottles.
Step 4. Add 0.25 mL of 150 mM fresh para-nitrophenyl phosphate solution, OR a stabilized substrate like Pierce 1-step pNPP, to each vial. We use Pierce 1-step pNPP because we tested it for stability (4 weeks at room temp in the dark, no change from baseline) and because it claims to have no toxic components.
Step 5. Add 2.5 units of bovine kidney alkaline phosphatase to each vial. This enzyme is sold in “units” (typically by the kU which is 1000 units). One unit of enzyme is the amount needed to produce one micromole of p-NP from p-NPP each minute.
We re-hydrate the enzyme at a concentration of 1.25 units per microliter in an enzyme buffer containing 50 mM Tris-Cl, 100 mM NaCl, and that has been adjusted to pH 8.0 with HCl. The enzyme buffer should be prepared in advance. We usually make 250-500mL of buffer at a time. The buffer will stay good for years if stored in a glass bottle, and once rehydrated the enyzme solution will stay good for “several months” at 4°C per the original characterizing paper.
We pipette 2 uL (2.5 units) onto disposable plastic cuvette caps that fit our test vials. The caps are then freeze-dried—using a vacuum pump with a cold trap—and packaged with silica gel dessicator packets in a tightly sealed container until ready for use. If using liquid enzyme solution stored in the fridge, freeze drying is not necessary.
Step 6. Place the caps on the top of each tube and press down to seal.
Step 7. Mix the contents of the tubes by turning upside down and back several times, wait 30 seconds while watching carefully.
Possible results:
1) If the second tube does not turn yellow, something went wrong. Repeat the test.
2) If the first tube does not change in 30 seconds or develops a yellow colour more slowly than the second tube, Levamisole is present.
3) If both tubes turn yellow at the same rate, Levamisole is not present.
Sensitive to 0.25—0.5% Levamisole (weight/weight).
From this site:
http://levamicoke.info/