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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
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1- Carrier gas supply2- Sample injection system3- Column configurationand column ovens4- Detection systems
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
4- Detection systems • 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
Application of GC • Qualitative analysis • Quantitative analysis
Stir-Bar Sorptive Extractionof 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.
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.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.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