Note: If one is testing the purity of a sample of veterinary liquid Nembutal, remove 6ml of liquid for testing and measure the exact volume using one of the graded pipettes. Add distilled water and proceed as described above.
Note: The quoted concentration on the bottle of the Nembutal to be tested is usually 65mg/ml. The original weight of the salt would be 6 x 65 = 390mg, and if pure ,would precipitate 350mg.
Set aside the dried pentobarbital crystals for use in the melting point test (MPT).
Note: The ACT Test is shown in the video ‘Purity Testing for Nembutal Powder’ but that the volumes used in the video differ slightly from the text description. In the video, only 200mg of powder was used for the test, and the process of serial dilution using small 5ml vinegar samples was not employed. This process of serial dilution and filtration avoids the possibility of re-absorbtion of the precipitate by over dilution, and the use of a larger (500mg) sample gives greater ACT test accuracy.
b) The Melting Point Test (MPT)
A pure test sample is expected to have a clearly-defined specific melting point. The melting point can be determined by using a thin-walled glass capillary tube to heat a small sample and then recording the temperature at which the sample melts (and changes colour).
For Nembutal, the test must be carried out on the free acid - not the sodium salt. Items needed for the test include a sealed glass capillary tube, thermometer (mercury or digital) with a range > 1500
C, and a glass container of cooking oil that can be heated slowly on the stove.
