Alkaline fraction

The organic phase recovered when the aqueous is basified to pH 9 to 10 with ammonium hydroxide or sodium hydroxide and shaken with chloroform-isopropanol or hexane-ethyl acetate. Contains the basic drugs with pKa above 7.5: opioids, tricyclics, SSRIs, antipsychotics, amphetamines, cocaine, LSD, atropine, nicotine and quinine.