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가스크로마토그래피기기의 구성과 기능

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© 2001 by KJS

운반기체의 종류

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시료주입법

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© 2001 by KJS

비분할 주입Splitless injection

분할 주입Split injection

섬광기화 주입법Flash vaporization

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관 형태와 오븐• 충전관 , 열린 모세관 : 길이 , 재질이 다양함 2 m 미만 ( 충전관 ), 10 m – 100 m ( 열린 모세관 ) 유리 , 용융 실리카 , 스테인레스스틸 , 테플론

• 오븐 : 관의 온도를 일정하게 유지 시키기 위함 0.1 도 단위의 정밀도 요구 시료의 평균 끓는점과 같거나 약간 높은 온도 유지 온도 프로그램 : 비점이 넓은 영역에 걸쳐 있는

시료

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관의 종류• 충전컬럼 : 내경 8 – 0.75 mm, 길이 1 – 3 m 4 mm 이상 : 분취용 , 2 mm : 분석용• 개방 모세관컬럼 : 내경 0.1 – 0.53 mm, 길이 5 – 150 m 분리성능 향상 , 낮은 시료용량 메가보어 (megabore) 컬럼 : - 내경 0.53 mm - 시료용량 개선 , 분취가능 (100 ng)

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Wall coated open tubular

GLC

Support coated open tubular

GLC

Porous layer open tubular

GSC

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Stationary phases

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© 2001 by KJS

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Chiral Stationary Phases (CSP)

CycloSil-B : 30% heptakis (2,3-di-O-methyl-6-O- t-butyldimethylsilyl)-b-cyclodextrin in DB-1701Similar: LIPODEX, Tr-bDEXm, b-DEX

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CycloSil-B : Similar: LIPODEX, Tr-bDEXm, b-DEX

CSP for GC

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Ideal detectors

1. 감도 , 안정성 , 재현성 , 직선성2. 온도범위 : 실온 – 400oC 3. 흐름속도와 무관4. 감응시간5. 신뢰도 , 사용의 편의성6. 분석물에 대한 동일한 감응도7. 선택적인 감응8. 비파괴적9. 정성분석

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Characteristics of detectors• 감응인자 (response factor RF) RF = 봉우리면적 / 성분무게• 직선농도범위 (linear dynamic range LDR) LDR = 최대검출농도 / 최소검출농도 = b/a

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LOD/LOQ• S/N ratio : signal to noise ratio• LOD : limit of detection (S/N = 2-3)• LOQ : limit of quantification (S/N = 10-20)

LOD LOQ

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Types of GC detectors1. Ionization detector ( 이온화 검출기 ) FID-flame ionization detector ( 불꽃이온화 검출기 ) NPD-nitrogen and phosphorus detector ( 질소 / 인 검출기 ) = TID-thermic ionization detector ( 열이온화 검출기 ) PID-photoionization detector ( 광이온화 검출기 ) ECD-elctroncapture detector ( 전자포획 검출기 ) HID-helium ionization detector ( 헬륨이온화 검출기 ) MSD-mass selective detector ( 질량 검출기 )2. Physical detector ( 물리적성질 검출기 ) TCD-thermal conductivity detector ( 열전도도 검출기 ) ELCD-electrical conductivity detector ( 전기전도도 검출기 )3. Optical detector ( 광학 검출기 ) FPD-flame photomeric detector ( 불꽃광도 검출기 ) AED-atomic emission detector ( 원자방출분광 검출기 )

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Thermal Conductivity Detector (TCD)

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Thermal Conductivity Detector (TCD)

• Very early detector for GC and it still has wide applications

• called as a katharometer or hot wire detector• Detect any compound, non-destructive• Hydrogen and helium have 6-10 times higher therma

l conductivity than all other organic compounds• Based on changes in the thermal conductivity of the

gas stream brought about by the presence of analyte molecules

• Heated filament oxidized by oxygen in the air

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© 2001 by KJS

FID

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© 2001 by KJSFlame Ionization Detector (FID)

• The most widely used and general detectors• Destructive of the sample• Consist of a hydrogen/air flame and a collector plate• Organic compounds produce ions and electrons that ca

n conduct electricity through the flame• The number of ions hitting the collector is measured• Selective for the compounds producing ions in flame• Selectivity: Compounds with C-H bonds• Sensitivity: 0.1-10 ng• Water generated by the flame - heating is necessary• Temperature: 250-300 °C; 400-450 °C• Explosion : hydrogen

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ECD

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Electron Capture Detector (ECD)

• Tritium or 63Ni (-line) causes ionization of the carrier gas and the production of electrons

• Organic molecules that contain electronegative functional groups, pass by the detector, they capture some of the electrons and reduce the current

• Popular detector for chlorinated insecticides and halocarbon residues in environmental samples

• Most sensitive, highly selective, non-destructive

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ECD

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NPD

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Nitrogen Phosphorous Detector(NPD)• Based on the increased ionization rate of the analyte i

n the presence of a heated alkali source• Thermionic emission (ionization) detector (TED,TID)• Similar in design to the FID• Strong response to organic compounds containing nitr

ogen and/or phosphorus• Sensitivity for N and P is similar to that of ECD• particularly useful for pesticides that contain phosphor

us

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PID

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FPD

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© 2001 by KJS

Flame Photometric Detector (FPD)

• Selective for sulfur and phosphorus • Used in environmental and food additive analyses w

here pesticides or herbicides containing sulfur or phosphorus

• Chemiluminescent reactions

• Wavelengthmax for sulfur is approximately 394 n

m and for phosphorus 510-526 nm• Interference filter is used between the flame and the

photomultiplier tube (PMT) to isolate the appropriate emission band

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© 2001 by KJS

FPD