Subnanogram assay for pilocarpine in biological fluids

A method for the determination of pilocarpine was developed in which the imidazole ring of pilocarpine was acylated with heptafluorobutyric anhydride, using triethylamine as a catalyst. After cleanup, the pilocarpine derivative was analyzed using GLC with electron-capture detection. The limit of sensitivity was 25-50 pg of pilocarpine, which had been subjected to the derivatization and cleanup procedures. The method was specific for pilocarpine, with the isopilocarpine derivative eluting prior to the pilocarpine derivative.