1. 가스크로마토그래피 기기의 구성과 기능

3. 운반기체의 종류

4. 시료주입법

6. 섬광기화 주입법 Flash vaporization
비분할 주입
Splitless injection
분할 주입
Split injection

7. 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
0.1도 단위의 정밀도 요구
시료의 평균 끓는점과 같거나 약간 높은 온도 유지
온도 프로그램: 비점이 넓은 영역에 걸쳐 있는 시료

8. 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)

12. Wall coated
open tubular
GLC
Support coated
open tubular
GLC
Porous layer
open tubular
GSC

13. Stationary phases

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

18. CSP for GC
CycloSil-B : Similar: LIPODEX, Tr-bDEXm, b-DEX

19. Ideal detectors 감도, 안정성, 재현성, 직선성 온도범위 : 실온 – 400oC 흐름속도와 무관 감응시간
신뢰도, 사용의 편의성
분석물에 대한 동일한 감응도
선택적인 감응
비파괴적
정성분석

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

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

22. Types of GC detectors 1. 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)

23. Thermal Conductivity Detector (TCD)

24. 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 thermal 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
Thermal Conductivity Detector (TCD)
1. Introduction
A TCD detector is a very early detector for gas
chromatography and it still has wide applications.
This device is sometimes called a katharometer and is
based upon changes in the thermal conductivity of the
gas flowing. Changes in thermal conductivity by the
presence of analytes, organic molecules cause a
temperature rise in the element which is sensed as a
change in resistance. The TCD is not as sensitive as
other detectors but it is non-specific and
non-destructive.
The use of thermal conductivity for the monitoring of
column eluents in gas chromatography goes back to the
earliest days of the techniques. Thermal conductivity
devices had been used for some time in gas analyzer
systems so their use in gas chromatography was a
natural development. This detector is able to detect any
compound. TCD is based on changes in the thermal
conductivity of the gas stream brought about by the
presence of analyte molecules. But it is not as popular as
the FID because of its generally poorer detection limits.
The advantage of the thermal conductivity detector is its
simplicity, its large linear dynamic range, its general
response to both organic and inorganic species and its
nondestructive character, which permits collection of
solutes after detection.
2. Mechanism
A detector cell contains an electrically heated filament
whose temperature at constant electrical power depends
upon the thermal conductivity of the surrounding gas. As
carrier gas containing solutes passes through the cell, a
change in the filament current occurs. The current change
is compared against the current in a reference cell. The
difference is measured and a signal is generated. The
resistances of the twin-detector pairs are usually
compared by incorporating them into two arms of a simple
Whetstone bridge circuit such as that shown in figure 1b.
The thermal conductivities of helium and hydrogen are
roughly six to ten times greater than those of most
organic compounds. Thus, in the presence of even small
amounts of organic materials, a relatively large decrease
in the thermal conductivity of the column effluent takes
place; consequently, the detector undergoes a marked
rise in temperature.
Selectivity: All compounds except for the carrier gas
Sensitivity: 5-20 ng
Linear range:
Gases: Makeup - same as the carrier gas
Temperature: °C
3. Instrumentation
Two pairs of TCDs are used in gas chromatographs. One
pair is placed in the column effluent to detect the
separated components as they leave the column, and
another pair is placed before the injector or in a separate
reference column. The resistances of the two sets of
pairs are then arranged in a bridge circuit. The heated
element may be a fine platinum, gold, or tungsten wire or,
alternatively, a semiconducting thermistor. The resistance
of the wire or thermistor gives a measure of the thermal
conductivity of the gas. Figure 1a is a cross-sectional
view of one of the temperature-sensitive elements in a
thermoconductivity detector system.
The bridge circuit allows amplification of resistance
changes due to analytes passing over the sample
thermoconductors and does not amplify changes in
resistance that both sets of detectors produce due to
flow rate fluctuations, etc. Figure 1b show the
arrangement of detector elements in a typical detector
unit. Two pairs of elements are employed, one pair being
located in the flow of the effluent from the column and the
other in the gas stream ahead of the sample injection
chamber. (These elements are labeled "Sample" and
Reference" in figure 1b.)
Figure 1. Schematic of (a) twin thermoconductivity
detector cell, and (b) an arrangement of two sample
detector cells and two reference detector cells

25. FID

26. Flame 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 can 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: ng
Water generated by the flame - heating is necessary
Temperature: °C; °C
Explosion : hydrogen
Flame Ionization Detector (FID)
The FID is one of the most widely used and generally applicable detectors for gas chromatography and hence is
used for routine and general purpose analysis. It is easy to use but destructive of the sample. FIDs consist of a
hydrogen/air flame and a collector plate. The construction of a typical ionization detector is shown in Figure 1.
FIDs are normally heated independently of the
chromatographic oven. Heating is necessary in order to
prevent condensation of water generated by the flame and
also to prevent any hold-up of solutes as they pass from
the column to the flame. With the flame extinguished, the
column end should be passed up through the jet and
then lightly held in position by slightly tightening the
coupling. Gradually draw the column end back into
detector jet until it is approximately mm below the jet
tip. Then tighten the coupling to retain it in position. Do
not over tighten couplings on capillary columns.
Several new applications for this detector were reported.
They included the determination of castor oil fatty acid
composition, an Empore disk elution method coupled with
injection port derivatization for the quantitative
determination of linear alkyl benzenesulfonates, the
determination of paracetamol and dicyclomine
hydrochloride, and dual-column hydrocarbon analysis.
Related to these routine applications was a simple and
efficient method for the determination of retention
parameters using a methane marker device.
Developmental advances in FID included several
modifications in design. A compact and low-fuel FID was
developed for portable GCs. Fuel flow rates were as low
as mL/min, and oxidant flow rates were in the range
of mL/min. Another improvement to FIDs was
reportedly made by the incorporation of a precombustion
chamber to mix the fuel and sample gas. Similarly, a
premixed FID was developed by adding hydrogen and air
at the same flow rate to the outlet of the capillary column.
This electrolyzer flame ionization detector (EFID) was
similar to a standard FID, except that the flame tip had a
narrower bore to prevent flame flashback and the entire
detector structure needed to be maintained at a
temperature greater than 100 °C in order to prevent water
condensation. Sensitivity of the EFID was similar to that of
the FID, but detectivity was improved by a factor of 2.
2. Mechanism
The effluent from the column is mixed with hydrogen and
air and then ignited electrically at a small metal jet. Most
organic compounds produce ions and electrons that can
conduct electricity through the flame. There is an
electrode above the flame to collect the ions formed at a
hydrogen/air flame. The number of ions hitting the
collector is measured and a signal is generated.
The organic molecules undergo a series of reactions
including thermal fragmentation, chemi-ionization, ion
molecule and free radical reactions to produce
charged-species. The amount of ions produced is
roughly proportional to the number of reduced carbon atoms
present in the flame and hence the number of molecules.
Because the flame ionization detector responds to the
number of carbon atoms entering the detector per unit of
time, it is a mass-sensitive, rather than a
concentration-sensitive device. As a consequence, this
detector has the advantage that changes in flow rate of
the mobile phase has little effects on detector response.
Functional group, such as carbonyl, alcohol, halogen,
and amine, yield fewer ions or none at all in a flame. In
addition, the detector is insensitive toward
noncombustible gases such as H2O, CO2, SO2 and NOx.
Selectivity: Compounds with C-H bonds. A poor response
for some non-hydrogen containing organics (e.g.,
hexachlorobenzene).
Sensitivity: ng
Linear range:
Gases: Combustion - hydrogen and air; Makeup - helium or nitrogen
Temperature: °C; °C for high temperature analyses
Figure 1. Flame Ionization Detector, FID

27. ECD

28. Electron Capture Detector (ECD)
Tritium or 63Ni (b-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
Electron Capture Detector (ECD)
1. Introduction
The ECD is one of a family of detectors invented by
Lovelock around the late 1950s and early 1960s. The first
member of the family was the macro argon detector and it
is rarely used today. The argon detector is an extremely
sensitive detector and can achieve ionization efficiencies
of greater than 0.5%. The detector did not achieve
popularity largely because its response was neither linear
nor predictable.
The ECD uses a radioactive Beta emitter (electrons) to
ionize some of the carrier gas and produce a current
between a biased pair of electrodes. When organic
molecules that contain electronegative functional groups,
such as halogens, phosphorous, and nitro groups pass
by the detector, they capture some of the electrons and
reduce the current measured between the electrodes. The
ECD is as sensitive as the FID but has a limited dynamic
range and finds its greatest application in analysis of
halogenated compounds.
The ECD is extremely sensitive to molecules containing
highly electronegative functional groups such as halogens,
peroxides, quinones, and nitro groups. It is therefore a
popular detector for trace level determinations of
chlorinated insecticides and halocarbon residues in
environmental samples. But is is insensitive toward
functional groups such as amines, alcohols, and
hydrocarbons.
Sensitive and selective for halogenated and other
electronegative compounds, the electron capture
detector (ECD) remains one of the most widely used GC
detectors. Novel applications reported during the past two
years include the following: the shipboard analysis of
halocarbons in seawater and air for oceanographic tracer
studies, the determination of chlorobutanol in mouse
serum, urine, and embryos, the measurement of
organochlorine compounds in milk products, the
identification of pesticides and other organochlorides in
water, organochorine pesticides in edible oils and fats,
metabolites from permethrin, and cypermethrin in foods,
and the determination of phenols from aqueous solutions
as bromo derivatives. A brominated internal standard was
found to be useful for the determination of organochlorine
pesticides.
Figure 1. Schematic of a gas chromatographic electron
capture detector
2. Mechanism
Electron-capture detector (ECD) operates in much the
same way as a proportional counter for measurement of
X-radiation. Here the effluent from the column passes
over a beta-emitter, such as 63Ni or tritium (absorbed on
platinum or titanium foil). An electron from the emitter
causes ionization of the carrier gas (often nitrogen) and
the production of a burst of electrons. In the absence of
organic species, a constant standing current between a
pair of electrodes results from this ionization process.
The current decreases, however, in the presence of
those organic molecules that tend to capture electrons.
The response is non-linear unless the potential across
the detector is pulsed.
Selectivity: Halogens, nitrates and conjugated carbonyls
Sensitivity: pg (halogenated compounds); pg
(nitrates); ng (carbonyls)
Linear range:
Gases: Nitrogen or argon/methane
Temperature: °C
3. Instrumentation
The electron capture detector was the first selective
detector to be invented for gas chromatography. In many
ways its origins go back to the argon ionization detector.
The construction of the detector is shown in Figure 2. The
internal chamber of the detector is kept as small as
practicable and is lined with radioactive beta-emitter
contained is a sealed foil. The source is normally either 3H
or 63Ni.
Figure 2. Electron Capture Detector, ECD
Based on this argon detector, a number of ionization detectors have
evolved from it in the development of the electron capture detector.
A diagram of an ECD is shown below:

29. ECD

30. NPD

31. Nitrogen Phosphorous Detector(NPD)
Based on the increased ionization rate of the analyte in 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 nitrogen and/or phosphorus
Sensitivity for N and P is similar to that of ECD
particularly useful for pesticides that contain phosphorus
Nitrogen Phosphorous Detector (NPD)
1. Introduction
The most common GC detector based on the ionization
of the analyte in the presence of a heated alkali source is
the nitrogen-phosphorus detector (also known as the
thermionic emission detector). This detector is similar in
design to the FID but with and important difference: an
electrically heated silicate bead doped with an alkali (such as
rubidium) salt is mounted between the jet and the collector.
The NPD is a highly sensitive but specific detector. It
gives a strong response to organic compounds
containing nitrogen and/or phosphorus. It would appear to
function in a very similar manner to the FID but operates
on an entirely different principle.
Compared with the flame ionization detector, the NPD is
approximately 500 times more sensitive for compounds
containing phosphorus and 50 times more sensitive for
nitrogen-bearing species. These properties make
nitrogen-phosphorus detector particularly useful for
detecting and determining the many pesticides that
contain phosphorus. The NPD is similar in structure to the
flame ionization detector. (Figure 1)
Developed to maturity, this detector was used in a number
of novel applications. Quantification of the metabolite
dichloroethylcyclophosphamide was preformed after direct
capillary gas chromatography without prior derivatization,
with a detection limit of 1 ng/mL. Other applications to
biological matrixes included determination of yohimbine in
commercial yohimbe products, study of a dietary
supplement alternative to anabolic steroids, nitrate
analysis in biological fluids, in which nitrobenzene was
produced from the dissolved nitrate, cyclophosphamide
metabolites, simultaneous quantification of two
antidepressant drugs, fluoxetine and desipramine, and
quantification of clozapine and zolpidem and zopiclone in
human plasma or serum. The NPD was also applied to
food analysis for the determination of fungicide residues
in cucumbers, herbicides in drinking water, and imazalil
residues in lemons. An important environmental
application of the NPD was the determination of
underivatized nitrophenols in groundwater. Simultaneous
determination of 15 organonitrogen pesticides was
accomplished with a flame thermionic detector. Also,
online determination of organophosphorus pesticides in
water by solid-phase microextraction techniques was
reported. One approach was investigated for the selective
detection of oxygenated volatile organic compounds.
2. Mechanism
The column effluent is mixed with hydrogen, passes
through the flame tip assembly, and is ignited. The hot
gas then flows around an electrically heated rubidium
silicate bead. The heated bead forms a plasma having a
temperature 600 to 800 °C. The combustion products of
nitrogen and phosphorus compounds interact with the
alkali metal ions by a complex series of reactions, which
produce thermionic electrons that are attracted to the
collector and give rise to the increase in current but the
mechanism of this reaction is not fully understood. The
number of ions hitting the collector is measured and a
signal is generated. For good reproducible results, careful
control of the flame, carrier gas and oven temperature are
required.
Selectivity: Nitrogen and phosphorous containing
compounds
Sensitivity: 1-10 pg. When compared with a standard
flame ionization detector the NPD is approximately 50
times more sensitive to nitrogen compounds and 500
times more sensitive to phosphorous compounds.
Linear range:
Gases: Combustion - hydrogen and air; Makeup - helium
Temperature: °C
Figure 1. Nitrogen Phosphorous Detector, NPD

32. PID

33. FPD

34. Flame Photometric Detector (FPD)
Selective for sulfur and phosphorus
Used in environmental and food additive analyses where pesticides or herbicides containing sulfur or phosphorus
Chemiluminescent reactions
Wavelength lmax for sulfur is approximately 394 nm and for phosphorus nm
Interference filter is used between the flame and the photomultiplier tube (PMT) to isolate the appropriate emission band
Flame Photometric Detector (FPD)
1. Introduction
The FPD is another type of flame detector. In contrast to
the oxygen-rich flame of FIDs, the FPD uses a
hydrogen-rich flame which is cooler. It has been used in a
number of applications, particularly in environmental and
food additive analyses where pesticides or herbicides
containing these sulfur or phosphorus. It is a selective
detector that is primarily responsive to compounds
containing sulfur and phosphorus. S- and P-containing
pesticides and their residues are of particular concern
and the subnanogram sensitivity of the FPD over the FID
and ECD have enabled trace analysis to be readily carried
out.
This device uses the chemiluminescent reactions of
these compounds in a hydrogen/air flame as a source of
analytical information that is relatively specific for
substances containing these two kinds of atoms. The
emitting species for sulfur compounds is excited S2. The
lambda max for emission of excited S2 is approximately
394 nm. The emitter for phosphorus compounds in the
flame is excited HPO (lambda max = doublet nm).
In order to selectively detect one or the other family of
compounds as it elutes from the GC column, an
interference filter is used between the flame and the
photomultiplier tube (PMT) to isolate the appropriate
emission band. The drawback here being that the filter
must be exchanged between chromatographic runs if the
other family of compounds is to be detected.
Figure 1. Schematic of a gas chromatographic flame
photometric detector
2. Mechanism
In this detector, the effluent is passed into a
low-temperature hydrogen/air flame, which converts part
of the phosphorus to an HPO species that emits bands
of radiation centered about 510 and 526 nm. Sulfur in the
sample is simultaneously converted to S2, which emits a
band centered at 394 nm. Suitable filters are employed to
isolate these bands, and their intensity is recorded
photometrically.
Selectivity: Sulfur or phosphorous containing compounds.
Only one at a time.
Sensitivity: pg (sulfur); 1-10 pg (phosphorous)
Linear range: Non-linear (sulfur); (phosphorous)
Gases: Combustion - hydrogen and air; Makeup -
nitrogen
Temperature: °C
3. Instrumentation
The instrumental requirements of PID are 1) a combustion
chamber to house the flame, 2) gas lines for hydrogen
(fuel) and air (oxidant), and 3) an exhaust chimney to
remove combustion products and the final component
necessary for this instrument is a thermal (bandpass)
filter to isolate only the visible and UV radiation emitted by
the flame. Without this the large amounts of infrared
radiation emitted by the flame's combustion reaction
would heat up the PMT and increase its background
signal. The PMT is also physically insulated from the
combustion chamber by using poorly (thermally)
conducting metals to attach the PMT housing, filters, etc.
Figure 2. Flame Photometric Detector, FPD

35. FPD