1. Gas Chromatography (GC)

2. Instruments for gas-liquid chromatography

3. 1- Carrier gas supply 2- Sample injection system 3- Column configuration and column ovens 4- Detection systems

4. 2- Sample injection system

5. 3- Column configurations and ovens
3-1 Open tubular columns
3-2 Packed columns
3-3 Temperature programming

6. 3-1 Open tubular columns Wall-coated open tubular (WCOT)
Support-coated open tubular (SCOT)
Fused-silica open tubular (FSOT)

7. 3-2 Packed columns
Solid support materials
Particle size of supports

8. 3-3 Temperature programming

9. 4- Detection systems Flame Ionization detectors (FID)
Thermal conductivity detectors (TCD)
Electron-capture detectors (ECD)
Flame photometric detector (FPD)

10. Flame Ionization detectors (FID)

11. Thermal conductivity detectors (TCD)

12. Electron-capture detectors (ECD)

13. Flame photometric detector (FPD)

14. The stationary phase Polydimethyl siloxane [OV-1,SE-30]
Poly(phenylmethyldimethyl)siloxane (10% phenyl) [OV-3,SE-52]
Poly(trifluoropropyldimethyl)siloxan [OV-210]
Poly(phenylmethyl)siloxane(50% phenyl) [OV-17]
Polyethylene glycol [Carbowax 20M]
Poly(dicyanoallyldimethyl)siloxane

15. Typical chromatograms with different stationary phases

16. Application of GC
Qualitative analysis
Quantitative analysis

17. Stir-Bar Sorptive Extraction of Trace Organic Compounds
Stir-bar sorptive extraction is a new solventless sample preparation method for the extraction and enrichment of organic compounds from aqueous matrices.

18. Stir bar sorptive

19. SBSE-GC-ECD/FPD in the Analysis of Pesticide Residues in Passiflora alata Dryander Herbal Teas
SBSE in combination with GC-ECD/FPD analysis is here applied to the determination of 11 pesticides (hexachlorobenzene,lindane,chlorothalonil,parathion methyl,parathion ethyl,fenitrothion,malathion,dieldrin,α- and β-endosulfan,and tetradifon) in herbal teas prepared with Passiflora alata Dryander spicked leaves.

20. Experimental procedure
Materials and reagents
Sample preparation
Capillary GC-ECD/FPD analysis
Thermal desorption-capillary GC/MS analysis

21. Results and discussion
SBSE-GC-ECD/FPD analysis of spiked water
SBSE-GC-ECD/FPD analysis of spiked P. alata Herbal teas
SBSE-GC-ECD/FPD analysis of P. alata Herbal teas prepared with spiked plant material

22. Fig 1. GC-ECD & GC-FPD profiles of the SBSE extract from a water sample spiked with 0.5 pg/µl of OC pesticides & 1.5 pg/µl of OP pesticides:(1)hexachlorobenzene;(2)lindane;(3)chlorothalonil;(4)parathion methyl;(5)fenitorthion;(6)malathion;(7)parathion ethyl;(8)α-endosulfan;(9)dieldrin;(10)β-endosulfan;(11)tetradifon.

23. Fig 2. GC-ECD & GC-FPD profiles of the SBSE extract from a P
Fig 2.GC-ECD & GC-FPD profiles of the SBSE extract from a P.alata herbal tea spiked with 0.5 pg/µl of OC pesticides & 1.5 pg/µl of OP pesticides.

24. Table 3.Octanol/Water Partitioning Coefficients(Ko/w),Water Solubility,Recoveries(R%),RSD% from Spiked Herbal Teas and from Herbal Teas Made from Spiked Plant Material for the OC and OP Pesticides Investigated.

25. Fig 3. GC-ECD & GC-FPD profiles of the SBSE extract from a P
Fig 3.GC-ECD & GC-FPD profiles of the SBSE extract from a P.alata herbal tea prepared with plant material spiked with 50 ng/g of OC pesticides & 150 ng/g of OP pesticides.

26. Table 5.Intermediate Precision Expressed as RSD(%),LOD,LOQ for Each OC & OP Pesticide Investigated.

27. References
SKOOG,HOLLER,NIEMAN;’’ PRINCIPLES OF INSTRUMENTAL ANALYSIS “;FIFTH EDITION,( ),1999
J. Agric. Food Chem.,51,27-33,2003

28. Thanks for your attention