Lab Report Spme.docx

BACHELOR OF SCIENCE ( HONS) APPLIED CHEMISTRY (AS245) LABORATORY REPORT ANALYTICAL SEPARATION METHODS CHM510 EXPERIMENT 5: ANALYSIS OF HYDROCARBONS IN COMMON FUELS BY SOLID-PHASE MICROEXTRACTION (SPME) AND GAS CHROMATOGRAPHY- MASS SPECTOMETRY (GC-MS) NAME

MUHAMMAD AMIRUL AFIFI BIN MAT YAKI

STUDENT ID

2018287232

PARTNER’S NAME

1. 2. 3. 4.

SITI SARAH BINTI ABDUL AZIZ NURHIDAYAH BINTI MOHAMAD NUR AFIQAH BINTI RUSMAN ANWAR

GROUP

AS2452S2

LECTURER’S NAME

NORAINI

DATE OF EXPERIMENT DATE OF SUBMISSION

ABSTRACT In the analysis the solid-phase miroextraction (SPME) and capillary gas chromatography or mass spectrometry (GC-MS) was developed for the identification of volatile compounds (hydrocarbon) in fuel. The samples was used is thinner, kerosene, unleaded petrol, diesel and one unknown. After the analyte was extracted by SPME in 20 minutes, it directly injected to the GC-MS with desorption time 80 seconds. After the analysis was done, the unknown was identifies as mixture of diesel and petrol because the hydrocarbon presence in the unknown is the same with the hydrocarbon compound in the petrol and diesel sample.

OBJECTIVE The objective of this experiment is to perform sample preparation by SPME and to identify the major hydrocarbons components in common fuel as (diesel, petrol, thinner and an unknown) by using SPME-GC-MS.

INTRODUCTION Modern gas chromatography-mass spectrometry (GC-MS) methods and equipment, with the sensitivity and structural information these methods provide, make GC-MS an excellent choice for field detection and identification of a range of organic chemicals. Numerous sampling techniques allow detection of GC-MS analytes in environmental matrices, although multiple sample-handling steps and use of extraction solvents increase the complexity and time needed to complete analyses. Solid phase microextraction (SPME) has been shown to be suitable for sampling environmental contaminants from air, water and soil for GC-MS analysis. Solid phase microextraction is simple and effective adsorption or desorption technique, eliminates the need for solvents or complicated apparatus for concentrating volatile or nonvolatile compounds in liquid samples or headspace. SPME is compatible with analyte separation by gas chromatography and provides linear results for wide concentrations of analytes. Gasoline, diesel and kerosene are all created from crude oil by variety of refining and distillation process. Each product is produced by the combination of multiple individual hydrocarbon compounds all of which have slightly different vaporization and boiling

temperatures. Gasoline is the combination of many lower boiling ranges while the middle boiling range compounds are used in differing proportions to create kerosene and diesel. The profile of hydrocarbons in oil may hence be used to characterize the oil. This enables the identification of the candidate source of oil spill cases. SAMPLE Accelerants : Unleaded petrol, diesel, thinner and kerosene. APPARATUS 1. SPME holder with 100 µm polydimethylsiloxane (PDMS) fibre. 2. Glass vial with septum. INSTRUMENT Gas chromatography equipped with mass selective detector(MSD) and a 30 m x 250 µm x 0.25 µm HP5-MS capillary column.

ANALYTICAL PROCEDURE a. Instrument set-up Injector temperature: 250 °C Detector temperature: 300 °C Carrier gas flow rate: 30 mL/s Column temperature: 60 ֯C to 170 °C at 10 °C/min

b. SPME procedure 1. The fibre (100 μm polydimethylsiloxane (PDMS)) was conditioned in the GC injector port for 10 minutes at 250 °C to remove any contaminants. 2. Diesel sample in vial at 50 °C was heated constantly while the fibre was exposed to the headspace of the vial for 20 minutes. 3. The fibre was withdraw into the needle and was pulled out from the vial and was immediately injected into the GCMS with desorption time of 80 seconds. 4. Step 1 until 3 were repeated for petrol, thinner and an unknown sample.

5. Petrol sample was run for 15 minutes and thinner sample was run for 10 minutes, while the unknown sample was run for 26 minutes depending on the completion of separation. 6. By using the mass spectra library, the major compounds (4 spots) in each sample were identified. RESULT AND CALCULATION a) Major compounds presence in petrol sample: Retention time,

Area,

min

%

2.77

16.90

Quality

Compound

90

Toluene

4.07

18.66

97 p-Xylene

6.02

5.13

95

Benzene, 1,2, 3-trimethyl-

6.93

1.31

91

Benzene, 1-methyl-3-propyl

b) Major compounds presence in diesel sample: Retention time,

Area,

min

%

10.66

13.77

Quality

Compound

94 Tetradecane

7.67

4.42

94

Undecane

12.47

8.96

96 Naphthalene, 2,6- dimethyl

13.27

4.56

97 Pentadecane

c) Major compounds presence in thinner sample: Retention time,

Area, Quality

min

%

2.73

89.01

Compound

94

Toluene

d) Compound of unknown that match with samples: Retention time, Samples

min

4.07

Area, Quality

Compound

%

10.34

97

p-Xylene

Petrol

6.05

4.69

94

Benzene, 1,2, 4-trimethyl-

7.70

2.61

94

Undecane

Diesel

11.00

2.06

94

Naphthalene, 2- methyl

DISCUSSION In this experiment, the sample preparation used solid phase microextraction (SPME) reduces the time necessary for sample preparation, decreases purchases and disposal costs of solvents and can improve detection limits. That is why the SPME was choosing in this analysis. From the experiment, there are four chromatogram obtain which are petrol, diesel, thinner and unknown. The method used was SPME where it used fiber to absorb the sample. Needle with fiber was put into the sample by head space method. The sample was volatile and thermally stable. So it does not need to dip it into the sample. The sample was volatile when it heated and the fiber absorbs the sample volatile and keeps it in the fiber. The first chromatogram obtained was petrol. A lot of components were found in this samples which were 16 components. Four of the major components were toluene with 90 quality and the retention time was 2.27 and has area% of 16.90, p-Xylene with 97 quality and its retention time was 4.07 with area% of 18.66, benzene, 1,2, 3-trimethyl- with 95 quality and its retention is 6.49 with area % are 5.13 and Benzene, 1-methyl-3-propyl with 91 quality and its retention time is 6.93 with area % of 1.31. The second sample was injected was diesel which had 17 components. The four highest quality components were heptadecane with 97 quality and its retention time was, naphthalene, 2,6- dimethyl with 96 quality and its retention time was, undecane with 94 quality and its retention time was and for the retention time and tetradecane with 94 quality and its retention time was . The third sample was thinner which had only one component which is toluene the major compound in the thinner sample with 94 quality. Unknown was the last sample injected. There were 29 components in the sample. However only the four highest qualities component were taken and the structures were taken from the mass spectrometer’s library. The components taken were p-Xylene with 97 quality and its retention time was

, benzene, 1,2, 4-trimethyl-with 94 quality and its retention time was ,

undecane with 94quality and for the retention time and naphthalene, 2- methyl with 94 quality and its retention time was

.

From this component, the result was compared with the other three standards. It was found that in the unknown contained mixture of petrol and diesel. This was due to the components of benzene and undecane as well as the compound of naphthalene in the unknown. The existent of the petrol compound in the unknown was shown by the detection of compound of 1,2,4-trimethyl benzene which had 6.02 minutes in retention time for petrol and 6.04 minutes

for unknown. Other than that, the compound of undecane had 7.67 minutes in retention time for diesel and 7.70 minutes for unknown.

CONCLUSION In conclusion, since hydrocarbon is volatile compound, the extraction procedure by placing the SPME fiber in the headspace above the sample can be extract the analyte and directly injected to the GC-MS. The components in the sample can be identified using the GC-MS where we can compare the obtained spectra with the mass spectra library. From this experiment, the objective of this experiment was achieved to determine the major compounds that present in the thinner, diesel, kerosene and petrol. The hydrocarbon that present in unknown are mixture of diesel and petrol.

REFERENCES 1. Nor’ashikin S., Ruziyati T., Mardiana S. (2012), Analytical Separation Methods Laboratory Guide (2nd edition) 2. Prof. Rozita, Lecture notes: Gas Chromatography (GC) and sample preparation for chromatographic Analysis. 3. Analysis of Hydrocarbons in Common Fuels https://studymoose.com/analysis-of-hydrocarbon-essay , Retrieved on 20th May 2019. 4. Solid Phase Microextraction Phase(SPME)-Sample preparation https://www.sigmaaldrich.com/analytical-chromatography/analyticalproducts.html?TablePage=9644384 , Retrieved on 20th May 2019. 5. Gas Chromatography / Mass spectrometry (GC-MS) http://www.cpeo.org/techtree/ttdescript/msgc.htm , Retrieved on 20th May 2019.