Now, 23 illicit drugs can be detected in saliva

Spanish scientists have developed a technique for detecting the presence of 23 illicit drugs and medicines in saliva samples.

Spanish scientists have developed a technique for detecting the presence of 23 illicit drugs and medicines in saliva samples.

The Directorate General of Traffic (DGT) in Spain is already using the technique as part of a European study on the frequency of alcohol and drug consumption amongst drivers.

"The saliva samples are collected by putting some cotton on the end of a special device placed under the tongue as if it were a lollipop, with an indicator that turns blue when there is a sufficient sample (0.5 ml). Each piece of cotton is then placed in a tube and labelled for analysis," said Manuel Lopez Rivadulla, one of the creators of the technique at the University of Santiago de Compostela (USC).

When it is the traffic police, which take samples from drivers, the tubes are placed in specially prepared containers and transported refrigerated to the lab.

The saliva is therefore processed and analysed using two combined systems: liquid chromatography (LC), by means of which the molecules searched for are separated, and tandem mass spectrometry (MS/MS), which enables the "unmistakable" identification of the different chemical compounds, said a USC release.

The method was published in journal Analytical and Bioanalytical Chemistry.