Surface ionization detector for detecting trace amounts of organic molecules

A method of providing an indication of the presence of trace amounts of organic molecules in a sample, for detecting one or more of cocaine, heroine, lidocaine and procaine in their base form or salt form, and tetrahydrocannabinol, the method comprising:

• i) mixing said sample in a carrier gas consisting of ambient air;
• ii) directing said sample and carrier gas over a heated bare metal surface maintained at a predetermined optimum temperature;
• iii) decomposing and ionizing said organic molecules present in said sample into ionized fragments, said decomposing and ionizing being effected over said heated surface;
• iv) subjecting said fragments to a predetermined polarization voltage for generating respective ionization currents;
• and
• v) measuring said ionization currents to provide an indication of the presence of said organic molecules, wherein said ionized fragments are positively charged and said polarization voltage is positive, for detecting one or more of cocaine, heroin, lidocaine, and procaine in their base form or salt form, and tetrahydrocannabinol.