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Solid phase extraction for an improved assay of physostigmine in biological fluids
Author(s) -
Hurst P. R.,
Whelpton R.
Publication year - 1989
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.1130030511
Subject(s) - chromatography , chemistry , solid phase extraction , extraction (chemistry) , detection limit , coulometry , elution , urine , physostigmine , sample preparation , high performance liquid chromatography , electrode , biochemistry , medicine , acetylcholine , electrochemistry , endocrinology
Abstract A simple, selective and very sensitive assay is described for the quantification of physostigmine in blood, plasma and urine. The most appropriate solid phase column was selected after a systematic investigation of nine types of phase. The conditions for solid phase extraction were optimized using [ 3 H]physostigmine so that the overall recoveries were >90%. Physostigmine was retained on alkaline treated cyanopropyl columns and eluted into the minimum volume of methanol, obviating the need for an evaporation step. Extracted samples were quantified by HPLC with a three electrode coulometric detection system. The limit of detection was 50 pg/mL for a 0.5 mL plasma sample. The precision (CV) for 0.5 mL plasma samples containing 50 pg was 8.1%. Application of the method to plasma, blood and urine samples is presented.