MOST of the world’s supply of cocaine comes from just three South American countries: Colombia, Peru and Bolivia. Much of it is headed for the United States and Europe. Law-enforcement officials from America patrol international waters in the Caribbean and eastern Pacific, hoping to seize cocaine shipments before they reach their intended destinations. When they succeed in nabbing any smugglers, contraband samples are sent to chemists to help determine the source.
The drug’s origins can be identified from telltale “fingerprints” formed by the chemical composition of the coca plant, from which cocaine is derived. These compounds vary naturally. The amount of nitrogen-containing compounds, known as alkaloids, differs between coca cultivars. And ratios of stable isotopes (non-radioactive atoms of the same element that contain different numbers of neutrons) are indicative of different regions. Typically, ratios of carbon-13 to carbon-12, which change according to temperature and altitude, and ratios of nitrogen-15 to nitrogen-14, which vary based on precipitation and soil conditions, are...Continue reading
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