Gas Chromatography (GC)

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Gas Chromatography(GC)
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Instruments for gas-liquid chromatography
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1- Carrier gas supply2- Sample injection
system3- Column configurationand column
ovens4- Detection systems
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2- Sample injection system
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3- Column configurations and ovens

• 3-1 Open tubular columns
• 3-2 Packed columns
• 3-3 Temperature programming

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3-1 Open tubular columns

• Wall-coated open tubular (WCOT)
• Support-coated open tubular (SCOT)
• Fused-silica open tubular (FSOT)

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3-2 Packed columns

• Solid support materials
• Particle size of supports

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3-3 Temperature programming
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4- Detection systems

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

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

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Typical chromatograms with different stationary
phases
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Application of GC

• Qualitative analysis
• Quantitative analysis

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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.

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Stir bar sorptive
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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,chlorothalon
  il,parathion methyl,parathion ethyl,fenitrothion,m
  alathion,dieldrin,a- and ß-endosulfan,and
  tetradifon) in herbal teas prepared with
  Passiflora alata Dryander spicked leaves.

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Experimental procedure

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

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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

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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)chlo
rothalonil(4)parathion methyl(5)fenitorthion(6)
malathion(7)parathion ethyl(8)a-endosulfan(9)di
eldrin(10)ß-endosulfan(11)tetradifon.
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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.
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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.
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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.
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Table 5.Intermediate Precision Expressed as
RSD(),LOD,LOQ for Each OC OP Pesticide
Investigated.
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References

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

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