Presumptive Tests for Cocaine

There are a number of presumptive tests for cocaine available from the literature. These are described below. 6.3.1.1 The Cobalt Isothiocyanate Test Although there are several presumptive tests available for cocaine and related compounds, none alone is specific to cocaine itself. A very simple test for cocaine is the addition of the material under investigation to a 2 (wt vol) solution of cobalt isothiocyanate in water. The presence of cocaine and related alkaloids results in a blue colour...

Quantification of Cocaine by UV Spectroscopy

This technique works particularly well if the cocaine is mixed with sugars, from which it can be easily separated by dissolution. Calibration standards are prepared, in methanol solution, at concentrations of 1.0, 0.5, 0.25, 0.125, 0.0625, 0.031 25 and 0.0156 mgml-1, using serial dilutions. A UV spectrum of a holmium filter is first measured to confirm that the instrumental set-up is performing satisfactorily. 0.50 1.00 1.50 2.00 2.50 3.00 3.50 Cocaine (mg ml-1) 0.50 1.00 1.50 2.00 2.50 3.00...