Screening Method B, including Derivatization with Acetic Anhydride

3 Screening Method B, including Derivatization with Acetic Anhydride 

Derivatization of the urine extract with acetic anhydride enables almost all the addictive substances recovered by means of the sample preparation process to be determined, at least down to the level of 100 ng/ml initially present in the urine. The only exception is the cocaine metabolite benzoylecgonine, as this can only be determined at this sensitivity by methylation or reaction with pentafluoropropionic anhydride. However, other cocaine metabolites, principally methylecgonine, are determined without difficulty by this method, so that the poor sensitivity of the benzoylecgonine method for determining cocaine consumption by urine analysis is not of any great significance. 

Injection volume Injector temperature Oven temperature Holding time 1 pi, splitless 280°C 70°C 1.5 min  

Temperature Heating rate End temperature Holding time 

Pressure program Rate of increase End pressure Holding time 

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