For HPLC analysis, several different adulterantswerealso added to the
cocaine standard in equal amounts. Theon-column concentrations of all of
the compoundswere100ng each. HPLC/UV-Vis run conditionswere
optimized to give themaximum separation and the shortest analysis time.
(SeeRunConditions #2). Total analysis timewas 8.0minutes. All
compoundswere baseline resolvedwith the exception of prilocaineand
lidocaine; Theywere resolvedby approximately 10% (seeTable #1). Since
they have almost identical retention times, positive identification of each
compound becomes very difficult as does accurate quantitation if both
compounds are present in the sample.
Table#1. Cocaine&Adulterant RetentionTimes.
Ultra C18
Compound RT (min.)
Procaine
2.39
Prilocaine
2.75
Lidocaine
2.78
Cocaine
3.25
Caffeine
3.94
Tetracaine
4.63
Phenacetin
7.74
Benzocaine
8.01
