Gas Chromatography (GC)

Instruments for gas-liquid chromatography

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

2- Sample injection system

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

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

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

3-3 Temperature programming

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

Flame Ionization detectors (FID)

Thermal conductivity detectors (TCD)

Electron-capture detectors (ECD)

Flame photometric detector (FPD)

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

Typical chromatograms with different stationary phases

Application of GC Qualitative analysis Quantitative analysis

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.

Stir bar sorptive

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.

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

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

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.

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.

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.

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.

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

References SKOOG,HOLLER,NIEMAN;’’ PRINCIPLES OF INSTRUMENTAL ANALYSIS “;FIFTH EDITION,(701-718),1999 J. Agric. Food Chem.,51,27-33,2003

Thanks for your attention