Since 1998 the mobile lab unit of the Office of the Cantonal Pharmacist (Health & Social Welfare Department, State of Bern, Switzerland) has been testing so-called "party drugs" on the dance floor. At more than 100 events, the team has analyzed over 1700 samples in cooperation with "Streetwork Zürich" and "Contact Bern". The mobile lab consists of four custom-made sub-units mounted in steel-framed racks on wheels, one for weighing and documentation, one for sample preparation and two with the equipment for chemical analysis (HPLC-DAD).

The lab is operated by two experienced technicians. Before analysis the interested customer is asked by the lab crew to fill out a questionnaire concerning information about the sample; thereafter every sample is digitally documented and characterized by physical appearance (form, weight, dimensions etc.).

Detailing collaboration between the on-site prevention team and the laboratory. Chemical analysis of party drugs gives one of three possible results. The findings may be a single active agent, several active agents, or indeed no active agent. Reliable analysis of the substances in a sample cannot be achieved by means of a simple "quick test" and is only possible by the use of a complex measurement chain, as shown in the following basic diagram: This arrangement applies to most modern chemical analysis measurement systems.

Due to the very sensitive analytical methods, only a representative part of the sample is used for further analysis. Sample preparation is quick and effective. The material is pulverised in a mortar and dissolved in methanol with the aid of an ultrasonic extractor. An internal standard is added as control. In most cases this extract still contains insoluble components, which must be filtered off before analysis. The clear sample solution obtained is transferred into a sample vial.

For chemical analysis of party drugs, separation and detection of different constituents of mixtures (active ingredients and fillers) is necessary. With the mobile lab we use High Performance Liquid Chromatography (HPLC) for the separation process. Our computer-controlled HPLC systems are equipped with DAD/UV-Vis Spectrometers (DAD=Diode Array Detector).


(Part of the separation system). This high-pressure pump delivers the solvent (with the dissolved sample) through the separating column to the detector.

The autosampler transfers the prepared sample from the vial into the measurement apparatus.

The "central unit" of the HPLC system serves to separate dissolved mixtures of substances into their constituents.

The chemical detector is positioned at the end of the column. It is the highly sensitive "eye" of the measurement chain and records substances which absorb ultraviolet light when they pass through the detector cell dissolved in the mobile phase. The detector provides two kinds of information about the molecules measured: their identity and their quantity. The whole process is continuously monitored with a computer system. Measurement signals are converted into graphical displays appearing on the computer screen. The two most important displays are the chromatogram and the UV spectrum. The chromatogram is a representation of the separation process. The UV spectrum is a characteristic constant for a particular substance.

Analytical results are available within about 20 minutes. The computer prints the results of the analysis as a report. The report consists of 3 parts: The header, the chromatogram, and the results (including identification and quantification).

The header contains details like: Filename, sample ID number, date of analysis, name of method, etc.

The chromatogram is a graphic visualisation of the separation process. Detected substances appear as "peaks".

The system compares the area-value of an integrated peak with the corresponding calibration of the active substance in the specified methods. This automatic process gives us a precise quantification.

Additionally, it is possible to get the UV spectra of the peak and compare it with our specific UV spectra library.