Paper Information

Title: 

APPLICATION OF SOLID PHASE MICROEXTRACTION ON THE EXTRACTION OF ANTIDEPRESSANTS, BENZODIAZEPINES, OPIATES AND LOCAL ANAESTHETICS FROM POST-MORTEM BLOOD SAMPLES

Type: SPEECH
Author(s): MOSADDEGH M.H.*,GARNER V.
 
 *PHARMACOLOGY DEPARTMENT, MDICAL SCHOOL, YAZD MEDICAL SCIENCES UNIVERSITY
 
Name of Seminar: IRANIAN CONGRESS OF TOXICOLOGY
Type of Seminar:  CONGRESS
Sponsor:  SOCIETY OF TOXICOLOGY
Date:  2004Volume 8
 
 
Abstract: 

Solid phase microextraction (SPME) is a new extraction technique, which uses a fused silica fibre coated with a polymeric coating to extract organic compounds from their matrix and directly transfer analytes into a gas chromatograph (GC) by thermal desorption in a GC injector. It is the major objective of this thesis to establish solid phase microextraction (SPME) as a variable sample preparation technique for screening, identification, and quantification of a wide range of different drug groups in post-mortem matrices. It is also a main purpose of this thesis to investigate the effects of parameters such as pH, temperature and addition of sodium chloride, which govern sensitivity and time efficiency of the technique. Sixteen blood samples were collected from post-mortem cases where the cause of death was suspected to be drug poisoning. The working internal standard solution of prazepam in methanol (10mL of 100mg/L) was added to 1mL of plasma and 1.5mL of 1 mol/L perchloric acid was then added. This was followed by vortex mixing for 3 min. The sample was then centrifuged at 3000 rpm for 10 min. The clear supernatant (2mL) was transferred into a beaker, containing 2mL of the appropriate buffer with 5mol/L NaCl. The pH was then adjusted. Place the polyacrylate fibre into the sample vial and extract the sample for 45 min at 45°C. Then put the fibre into the GC injector to release the absorbed drugs. 8000 Top Carlo Erba gas chromatograph, HP-5 fused silica capillary column and ultra pure helium as carrier gas, in combination with a Fisons MD 800 quadrupole mass spectrometer in EI+ mode at 70eV was used for the analysis of the samples. A computer equipped with Masslynx software, which was also devoted to data acquisition and processing, controlled the whole procedure including the various operating of the gas chromatograph and mass spectrometer. Mass spectrometer data were collected in full scan mode; searching the related spectra in commercial libraries NIST, LIBTX and Wiley identified the drugs. The results from this study show that the SPME procedure is useful for the extraction of the majority of the drugs from post-mortem samples. However, there are some limitations for the extraction of a few of the drugs. Probable causes of this include heat instability, deterioration during a long period of storage and retention of the drugs by the SPME fibres coatings. These problems can be solved by derivatising the drugs to stable derivatives or compounds that do not bind irreversibly to the SPME fibres. It had the highest rate of detection compared with HPLC, colorimetry and immunoassay methods. It is potentially a method that could be employed on a regular basis because of its high detection rate, ease of use and lack of need of pollutants such as organic solvents or radioisotopes.

 
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