ABSTRACT
Solid-phase extraction (SPE) by means of disposable columns has become a widely accepted technique for sample pretreatment in toxicology, both for directed analyses and for screening analyses. However, the sample capacity in SPE is usually limited to a few millilitres. Therefore, we have investigated to what extent these problems can be overcome by using Empore extraction disks, consisting of chemically modified C-8 reversed-phase silica, embedded in an inert polytetrafluoroethylene (PTFE) matrix. Human urine was selected as the matrix and dexetimide and mepyramine were initially used as test drugs because these drugs were available in tritiated form. Additional drugs investigated included codeine, hexobarbital, imipramine, methamphetamine, and nitrazepam. In these investigations, the sample capacity for untreated urine was at least 25 mL, and analyte quantities up to 250 micrograms could be retained by these filters. Washing with water/methanol mixtures was successful in removing substantial amounts of endogenous interferences, and methanol proved to be an acceptable eluent. Thus, these disks seem to have interesting potential for toxicological analysis in that sample concentration and cleanup can be achieved at the same time.
Subject(s)
Dexetimide/urine , Pyrilamine/urine , Barbiturates/chemistry , Barbiturates/isolation & purification , Barbiturates/urine , Codeine/chemistry , Codeine/isolation & purification , Codeine/urine , Dexetimide/chemistry , Dexetimide/isolation & purification , Filtration , Hexobarbital/chemistry , Hexobarbital/isolation & purification , Hexobarbital/urine , Humans , Imipramine/chemistry , Imipramine/isolation & purification , Imipramine/urine , Methamphetamine/chemistry , Methamphetamine/isolation & purification , Methamphetamine/urine , Molecular Structure , Nitrazepam/chemistry , Nitrazepam/isolation & purification , Nitrazepam/urine , Prazepam/chemistry , Prazepam/isolation & purification , Prazepam/urine , Pyrilamine/chemistry , Pyrilamine/isolation & purificationABSTRACT
We have developed a new extraction technique for nitrazepam and diazepam using Samplex C-18 column. The blood-extractions containing diazepam and nitrazepam were diluted with acetonitrile-water 7:3 eluent. Diazepam and nitrazepam were isolated using liquid-liquid extraction technique. The blood-extracts were diluted with chloroform-ethanol 1:1 and they were evaluated by using OPLC method. Evaluation was done by TLC-scanner (Shimadzu). The efficiency and sensitivity of the methods have been compared.