Analysis of Hydrocarbon in Common Fuels by Spme (solid Phase Microextraction) and Gc-Ms (gas Chromatography-Mass Spectrometer)

EXPERIMENT 5

ANALYSIS OF HYDROCARBON IN COMMON FUELS BY SPME (SOLID PHASE MICROEXTRACTION) AND GC-MS (GAS CHROMATOGRAPHY-MASS SPECTROMETER)

NAME                                  :   MOHD IQBAL BIN NORAZMAN

STUDENT ID                       :   2015840192

GROUP                               :   AS2452s

PARTNER’S NAME       :   1. AKMAL ARSYAD BIN MOHD. RAFFI

                                       2. MUHAMMAD RAHIMI BIN ZAHURI        

                                       3. SYARAFUDDIN BIN MOHD SHAMSIBY

DATE OF EXPERIMENT   :  

DATE OF SUBMISSION    :

Introduction

In the analysis of the solid phase microextraction (SPME) Gas Chromatography / mass spectrometry (Gc/Ms) was developed for the identification of volatile components (hydrocarbon) in fuel. Sample used were petrol, diesel, thinner and unknown. After the analyte was extracted by SPME for 20 minutes, it directly injected to GC/MS with desorption time 80 seconds. After analysis was done, result was stated and unknown was identified because the hydrocarbon presence in the unknown was the same with hydrocarbon compound in standard.

Solid Phase Microextraction, a simple effective adsorption/desorption technique, eliminate the need for solvents or complicated apparatus for concentrating volatile or non volatile compound in liquid samples or headspace. SPME was compatible with analyte separation/detection by gas chromatography or HPLC (High Performance Liquid Chromatography), and provide linear results for wide concentration of analytes. By controlling the polarity and thickness of the coating on the fibre, maintaining consistent sampling time, and adjusting several other extraction parameters. An analyte can ensure highly consistent quantifiable results from low concentration of analytes.

Analytes of volatile or semi volatile organic environmental pollutants, flavour or fragrance components, and many other samples usually begin with concentrating the analytes of interest through liquid-liquid extraction, purge and trap headspace or various other techniques. These procedures typically require excessive time, complicated equipment and/or extravagant use of organic solvents. SPME on adsorption/desorption technique developed at the University of Waterloo (Ontario, Canada), eliminates the need for solvents in an experiment. SPME is microextraction technique, which means amount of extraction solvent is very small compared to the sample. As a result, exhaustive removal of analytes to the extracting phase doesn’t occur rather an equilibrium, is reached between sample matrix and the extracting phase.

SPME passively extracts organic compound and concentrates them onto a thin, fused silica fiber coated with a stationary phase material. The component in a sample was identified by comparing with the mass spectra library. The quality of a component must been taken 90% and above. The purpose of this experiment is to perform sample preparation by SPME and to identify the components of hydrocarbon in common fuel using SPME-GC-MS.

Method

The fiber (PDMS) was conditioned in the GC injection port at 250oC for at least 10 minutes to removed contaminants. Sample used in this analysis were petrol, diesel, thinner and an unknown compound. First sample used was unleaded petrol where approximately 5mL of it was added in a glass vial and place the vial on a hot plate and sample was heated to 500C while agitate it by using magnetic stirrer. Then, the SPME fiber was exposed to the headspace of the vial for 20 minutes. After that, the fibre was withdraw into the needle and pulled out from the vial and immediately injected into GC-MS with desorption time 80 seconds. After desorption period, the needle was withdrawn from the injection port and chromatography process continued. After the chromatogram was obtained, the major compounds in each sample were identified by using the mass spectra library. Four compounds that have higher quality were selected. All the steps were repeated for the next three samples.

Results

1. Petrol

1. Diesel

1. Thinner

1. Unknown

Compound of unknown that match with compound in petrol.