Act directly on dopaminergic and norepinephrinergic neurotransmitter systems, especially the limbicsystem
Positive drug screening test cannot differentiate casual user from chronic or habitual user, likewise detect the time frame of using the drug or dose of the drug taken
Different analyte selectivity is based on different physiochemicalprinciples of separation without change in instrumental hardware, a distinct advantage of this technique
Recent variant of TLC that includes the advantage of HPLC