FUNDAMENTAL PRINCIPLE OF ALCOHOL ANALYSIS USING HS-GC-FID INSTRUMENT AS A PROTOTYPICAL METHOD THAT UTILIZES FOR ROUTINE WORK IN FORENSIC TOXICOLOGY

Abstract

Background

Gas chromatography (GC) is a significant method used widely to identify and quantify different types of analytes. The combination of high ability of separation power in GC with various types of detectors makes this method an important⁾ .Gas chromatography is greatly used for volatile compounds that losses the analyte during sample preparation, have low molecular mass vapor pressure (under) less than 250 ⁰C and decompose at 400⁰CThe aim of this theoretical and practical laboratory is to introduce fundamental principle of HS-GC-FID instrument as a prototypical method that utilized for routine work in forensic toxicology.

Objective

• The aim of this theoretical and practical laboratory is to introduce fundamental principle of HS-GC-FID instrument as a prototypical method that utilized for routine


• Understand the foundation of headspace gas chromatography, explain the function of each major part in the instrument and determine the concentration of ethanol in blood as it is important factor in forensic toxicology using data obtained from analysis.

Method

Preparing calibration in different concentration (10,25,50,100,200,300,400) mg/dl, three controls 30, 80 and 300mg/dl and unknown sample. Each have DRF number by using compudil 300 diluter hook and tucker instrument to dilute 200mgl of calibrators, control and sample unknown with 500mgl of internal standard(n-propanol150mg/dl) and put in headspace vials then seal vial after that heat and shake vials to allow internal standard and any ethanol present to equilibrate between sample and headspace. Now the calibrators, controls and sample are ready to transfer to GC instrument CLARUS 500 Cofuigured with FID ionization and Turbomatrix 110 headspace sampler. The heater is 50 ⁰ C inside the turbo and 150C is the oven temperature CALRUS. The sample stay minutes in the heater then injected to oven at 150C and the temperature is constant while all samples are going through column.

Results

Shows that two out of three controls are within the range are lying between +2SD when compared with QC chart in the appendix and just control 80 is out of range due to consult technical manager. The R² value from the graph (3) is 0.9999, according to criteria of acceptability is acceptable. In case of road traffic the CV for controls 80 and 300 and for the sample unknown is 0.8579,1.4217 and 0.7156 respectively are valid due to criteria of acceptability.

Conclusion

The investigation of the unknown blood sample 13/008 that determined by GC-HS-FID have two detectors each detector give result and both results tested positive for alcohol and the dependable result was from combine both detectors to ensure the result and that also tested positive for alcohol.