Gas chromatography GC

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Contents
• Introduction
• Hardware
• GC Preinjection
• GC Basic Components
• Analysis
• Applications

Gas chromatograph
An analysis technique in which the sample
mixture is injected, vaporized into a stream of
carrier gas (as nitrogen or helium) moving
through a column containing a stationary
phase, separated into its component
according to their affinity for the stationary
phase and detected.

Separations
• Boiling points is The number one factor to
consider in separation of compounds on
the GCs.
• Differences in polarity of the compounds
is only important if you are separating a
mixture of compounds which have widely
different polarities.
• Column temperature, the polarity of the
column, flow rate, and length of a column
are constant .

Hardware
• Manual Injection.
• Automatic Injections.
• Injectors
• Columns
• Oven
• Detectors
• Carrier Gas

Samples injection
Liquid introduction by syringe
• Most commonly used technique
• Different syringe types manual and
automatic
Other techniques and devices
• Sampling valve (gas or liquids)
• Head-space (liquids or solids)
• Purge and trap (water)
• Thermal desorption (solids)
• SPME (vapors, liquids or solids)
• Pyrolizer (solids)

Manual Injection
Micro Syringes
• Are used to introduce a known volume
of a liquid or gas samples.
Adaptor
• Can be used to help control the volume
injected.
Syringe injection
• Samples should be injected as a plug.
• Rapid and consistent injection is
necessary in order to obtain Acceptable
precision
Injection Volume
• Liquids 0.1-10 µl is typical
• Gases 0.5- 5 ml is typical

Hot Needle injection
1. Draw sample into syringe barrel.
2. Draw 2-3 ul air into barrel.
3. Inset needle into injection port and allow to heat
for a few seconds.
4. Rapidly inject sample and withdraw the needle.
5. This insure that all sample is injected and the hot
needle assists in solvent volatilization.

Normal injection
1. Rinse the syringe with your sample at
least twice .
2. Draw up the suggested amount of sample
into the syringe.
3. Pull up about 1-2 ul of air, This will give a
signal showing the beginning of the
elution.
4. Insert the needle through the injection
port and septum in one movement.
5. Quickly push the plunger.

Automatic Injection
Sample loading
• Sample capacity: 8 Vials
• Max. vial capacity: 2 ml
• Injections/vial: 0-99
Syringes
• Standard sampling: 10µl
• Micro volume sampling: 5µl
Injection parameters
• Max volume: 5µl
• Min. Volume :0.1µl
• Increments: 0.1µl steps
• Viscosity Delay: Yes/No
Auto Injector AI 3000

Autosampler
Sample loading
• Sample capacity: 105 Vials
• Max. vial capacity: 2 ml
• Injections/vial: 0-99
Syringes
• Standard sampling: 10µl
• Micro volume sampling: 5µl
Injection parameters
• Max volume: 5µl
• Min. Volume :0.1µl
• Increments: 0.1µl steps
• Viscosity Delay: Yes/No
Auto Sampler AS 3000

Auto Sampler TriPlus
• Large sample vial capacity Max 2 trays installed
• Simultaneously 1, 2 and 2.5 ml vials (up to 300 vials)
• Syringe size: 5, 10, 100 and 250 µl.
• Self recognized syringes and trays
• Washing station: 4 x 10ml or 2 x 100ml;
multiple Solvent rinsing supported
• Rapid Mode: Allows to perform cleaning operations during GC run or
cooling time.
• Suitable for Ultra Fast GC requirements, eliminating dead times
between successive runs.

Head space
Head-space gas analysis
• Volatiles reach equilibrium at STP
• An aliquot of headspace is total in liquid
and gas phase
• Conc. in gas proportional Conc. In liquid
phase With headspace matrix left behind
• Clean and gentle chromatography
Representative of sample

Head-Space Applications
1. Determination of residual volatile solvents
in pharmaceutical.
2. Blood alcohol analysis.
3. Determination of volatile hydrocarbons in
waste water.
4. Determination of di-acetyl and dichetones
in beers.
5. Monomers in polymers determination.
6. Determination of out-gassing solvents
from packages.
7. Flavor profiles in drinking beverages or
foods (cheese).

Cold and Trap
• Allows the analysis of trace of compounds in large
volumes of gaseous samples.
• The column can be cooled down to -150 °C by the
action of the liquid nitrogen,
• So to trap (i.e. to reconcentrate) the volatile
compounds contained in the sample.
• When the trapping is completed, the tube is
heated with a fast temperature programming rate
(°C/s), reaching temperatures up to 400 °C, so to
transfer the trapped compounds into the analytical
column

GC Basic Components
Injector
Column
OvenDetector
Carrier
Gas

1. Injector
The injection port Is a hollow, heated, glass-lined cylinder
• The injector is heated so that all components in the
sample will be vaporized.
• If the temperature is too low, separation is poor and
broad spectral peaks should result or no peak develops at
all.
• If the injection temperature is too high, the specimen
may decompose or change its structure.
• The temperature of the sample port is usually about 50°C
higher than the boiling point of the least volatile
component of the sample.

Injection Techniques
Vaporizing.
The liquid sample is evaporated prior to be
transferred to the separation column.
• Split Spliless: SSL (permanently hot)
• Programmed Temperature Vaporizer: PTV
• Direct: PKD, PPKD (permanently hot, low
resolution columns)
Nonvaporizing.
The liquid sample evaporates into the separation
column (or a precolumn)
• Cold On Column: OC (permanently cool)

Septa
• Ensure optimal performance of your GC
instrument with bleed and temperature.
• Made of low-bleed silicone, have
excellent mechanical properties, are ideal
for demanding GC and GC-MS
applications, and may be used reliably up
to 400 °C.
• Septum must be replaced at least after
200 injections.

Injector Types
1. Split/ Splitless Injector
2. On-Column Injector
3. High Oven Temperature On-Column
Injector
4. Large Volume On-Column Injector
5. Packed Column Injector
6. Purged Packed Injector
7. Programmable Temperature Vaporizing
Injector

1. Split/Splitless Injector (vaporizing injector)
Split mode
• The split vent is open, part of the sample
go into the column.
• When analyzing high concentration or
neat samples.
• Yields the sharpest peaks if the split gas is
properly mixed.
• Standard for capillary columns.

Splitless mode
• The split vent is closed, most of the
sample go into the column.
• When analyzing low concentration or
diluted samples.
• Splitless times of ~ 1 minute are typical.
• Standard for capillary columns.

2. On-Column Injector
Non- vaporising injectors
• The sample is transferred as a liquid directly
inside the column under the oven
temperature control.
• The sample evaporation takes place inside the
column.
• Sample doesn’t come in contact with any
“column-external” device
• No vaporization step at a temperature above
that of the column

Cooling
Primary cooling
• Permanently active fan
• Keep the injector head at room temperature independently from oven
temperature
Secondary cooling
• Temporary stream of compressed air
• Avoid evaporation from the needle even at oven T close or slightly higher than BP
• Reduces the length of the flooded zones
• Avoid liquid backflow reducing the vapor pressure at the plug front
• More efficient and rapid cooling of the injector base after a temperature ramp
• Cooling Time, The amount of time the secondary cooling stays on after the start
the injection.

3. High Oven Temperature On-Column Injector
• The OCI is the same as the regular cold on column
except that a cooling jacket is installed in the GC
oven around the head of the column.
• This allows a cold on column injection with a high
oven temp.
Temperature (°C).
• The temp. checkbox checked for this option to be
used.
• This specifies cooling jacket temp. during injection.
• Duration (min) the duration of the jacket cooling
from the start of the run.

4. Large Volume on column injector
• LV-SL injection overcomes the limitation of the maximum sample
volume to 1-2 µL of classical splitless injection by exploiting the
Concurrent Solvent Recondensation technique (CSR).
• CSR technique allows injection of large volumes by combining a
restricted evaporation rate with an accelerated sample transfer granted
by the pressure surge generated by solvent evaporation and by the
quick solvent recondensation in a precolumn.
LV-SL has the following advantages:
• It is simpler because it allows injections of up to 50 µL in a conventional
split/splitless injector without any special tuning of operating
parameters;
• It is robust versus sample by-products or contaminants and extremely
suitable for food matrices.

5. Packed Column Injector
• The PKD is used for injections with the
sample vaporizing directly in the column.
• The PKD standard injector accepts metal
or glass packed columns.
• The injector temperature may range from
ambient to 400 °C. Injector temperature is
regulated by a temperature controller in
the GC CPU board and monitored by a
platinum wire sensor.

6. Purged Packed Injector
• The Purged Packed (PPKD) column injector
is a packed column injector with a septum
purge.
• The PPKD standard injector accepts wide-
bore capillary columns.
• The sample vaporizes in a liner and enters
the wide-bore capillary column.
• The injector temperature is controllable
from 50 °C to 400 °C.
• You should use high temperature septa
with a longer life expectancy.

7. Programmable Temperature Vaporizing Injector
• Can vary the temp. during injection in both split
and Splitless.
• Can eliminate many of the unwanted effects , such
as distillation of the sample within the needle
and large vapor clouds inside injector chamber.
• In Constant Temperature (CT) mode, the PTV
functions like a split/splitless injector.
• Sample volumes are lower than when using S/SL
injector because of the smaller PTV liner volume .
• Can analyze relatively dirty samples that can not be
analyzed using a traditional on-column.

Good injector
1. Capable to quantitative accept a broad volatility range.
2. Low discrimination.
3. To handle dirty and clean matrices.
4. With dirty matrices reduces sample clean-up and preserves the
column.
5. With clean matrices boosts sensitivity with LVI techniques .
6. Extremely inert.
7. Able to handle polar/active compounds.
8. Provide optimum band shape.

2. Column
The column
• Is where the chromatographic separation
of the sample occurs.
• Several types of columns are available for
different chromatographic applications:
• The heart of the system.
• It is coated with a stationary phase which
greatly influences the separation of the
compounds.

Stationary phase
• Solid resin packed in a column , or
• Liquid supported by course paper or
• Inactive solid over which a mixture passes.
Each component of the mixture differs in the
way it adheres to this phase and therefore
travels along it at a unique rate.

The Adsorbents
There are two types of packing employed in GC, the adsorbents and the supports, on
which the stationary phase is coated.
There are both inorganic and organic types of adsorbents.
• Alumina, in an activated form, is used to separate the permanent gases and
hydrocarbons up to about pentane.
• Silica gel It is used for the separation of the lower molecular weight gases and
some of the smaller hydrocarbons sulfur gases, hydrogen sulfide, sulfur dioxide
and carbon disulfide.
• Synthetic zeolites used for the separation of hydrogen, oxygen, nitrogen,
methane and carbon monoxide and also rare gasses.

Types of Stationary Phase
POLYSILOXANES
• The most common stationary phases.
• They are available in the greatest variety and are the most
stable, robust and versatile.
• The most basic Poly Siloxane is the 100% methyl
substituted
POLYETHYLENE GLYCOLS
• They are less stable, less robust and have lower
temperature limits than most Poly Siloxane.
• must be liquids under GC temperature conditions.

Inactive Solid Supports
• There have been a number of materials
used as supports for packed GC columns
including,
• Celite (a proprietary form of a
diatomaceous earth), fire-brick (calcined
Celite), fire-brick coated with metallic
silver or gold, glass beads, Teflon chips
and polymer beads.
• Polystyrene beads

Column Types
Conventional
• 1/8-1/4 OD
• 6-8 feet in length
• Stainless steel or glass tube
Preparative
• >1/4 OD
• > 10 feet in length
Capillary
• 0.1- 0.5 ID
• 10 – 100 meters in length

Factors Affecting Column Separations
• Volatility of compound: Low boiling (volatile) components will travel faster through the
column than will high boiling components
• Polarity of compounds: Polar compounds will move more slowly, especially if the column is
polar.
• Column temperature: Raising the column temperature speeds up All the compounds in a
mixture, “Columns have lower and upper temperature limits”.
• Column packing polarity: Usually, all compounds will move slower on polar columns, but
polar compounds will show a larger effect.
• Flow rate of the gas through the column: Speeding up the carrier gas flow increases the
speed with which all compounds move through the column.
• Length of the column: The longer the column, the longer it will take all compounds to elute.
Longer columns are employed to obtain better separation.

Loss of Separation or Resolution
• Contaminated column.
• Damaged stationary phase.
• Different column temperature, carrier
flow rate or column.
• Large changes in the sample
concentration.
• Improper injector operation.

Column Damage
• Column breakage
• Column bleed
• Thermal damage
• Oxygen damage
• Chemical damage

3. Oven
• The use of a temperature programmed for
the column oven influences the separation
process significantly and is used for
optimization of time and peak separation.
• The oven must not be opened when the
oven temperature is above room
temperature.
• Never turn off the nitrogen flow unless the
column and oven are at room temperature.

The Oven Capabilities
• Temperature range 5 °C above ambient to
350 °C
• Temperature programming - up to six
ramps
• Maximum run time - 999.99 minutes
• Temperature ramp rates - 0 to 120°C/min
• The oven accommodates one inlet, one
detector, and one column

Multiple-ramp temperature programs
• A multiple-ramp temperature program
changes the oven temperature from an
initial value to a final temperature, but
with various rates, times , and
temperatures in between.
• Multiple ramps can be programmed for
temperature decreases as well as
increases.

4. Detector
The part of a gas chromatograph
which signals the change in
composition of the mixture passing
through it.

Detector types
1. Electron Capture Detector.
2. Flame ionization Detector.
3. Nitrogen Phosphors Detector.
4. Thermal Conductivity Detector.
5. Flame Photometric Detector.
6. Photo ionization Detector.
7. Electrolytic Conductivity Detector.
8. Mass Spectrometric Detector.

1. Electron Capture Detector (ECD)
Mechanism:
• Electrons are supplied from a 63Ni foil lining the detector cell. A current is generated in the
cell. Electronegative compounds capture electrons resulting in a reduction in the current. The
amount of current loss is indirectly measured and a signal is generated.
• Selectivity: Halogens, nitrates, conjugated carbonyls
• Sensitivity: 0.1-10 pg (halogenated compounds);
1-100 pg (nitrates); 0.1-1 ng (carbonyls)
Linear range: 1000-10000
Gases: Nitrogen or argon/methane
Temperature: 300-400°C

2. Flame ionization Detector (FID)
Mechanism:
• Compounds are burned in a hydrogen-air flame.
• Carbon containing compounds produce ions that are attracted
to the collector.
• The No. of ions hitting the collector is measured and a signal
is generated.
• Selectivity: Compounds with C-H bonds.
• Sensitivity: 0.1-10 ng
Linear range: 105 -107
Gases: Combustion hydrogen and air; Makeup He or N2
Temperature: 250-300°C,and 400-450°C for high temp.

3. Nitrogen Phosphors Detector (NPD)
Mechanism:
• Compounds are burned in a plasma surrounding
a rubidium bead supplied with hydrogen and air.
• Nitrogen and phosphorous containing compounds
produce ions that are attracted to the collector.
• The number of ions hitting the collector is measured
and a signal is generated.
• Selectivity: Nitrogen and phosphorous
• Sensitivity: 1-10 pg
Gases: Combustion - hydrogen and air; Makeup - Helium

4. Thermal Conductivity Detector (TCD)
Mechanism:
• A detector cell contains a heated filament with an applied current. 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.
• Selectivity: All compounds except for the carrier gas
• Sensitivity: 5-20 ng
Gases: Makeup - same as the carrier gas

5. Flame Photometric Detector (FPD)
Mechanism:
• Compounds are burned in a hydrogen-air flame. Sulfur and phosphorous containing
compounds produce light emitting species (sulfur at 394 nm and phosphorous at 526 nm). A
monochromatic filter allows only one of the wavelengths to pass. A photomultiplier tube is
used to measure the amount of light and a signal is generated.
A different filter is required for each detection mode.
• Selectivity: Sulfur or phosphorous containing compounds.
Only one at a time.
• Sensitivity: 10-100 pg (sulfur); 1-10 pg (phosphorous)
Linear range: Non-linear (sulfur); 103 -105 (phosphorous)
Gases: Combustion - hydrogen and air; Makeup - nitrogen

6. Photo ionization Detector (PID)
Mechanism:
• Compounds eluting into a cell are bombarded with high energy photons emitted from a
lamp. Compounds with ionization potentials below the photon energy are ionized. The
resulting ions are attracted to an electrode, measured, and a signal is generated.
• Selectivity: Depends on lamp energy. Usually used for
aromatics and olefins (10 eV lamp).
• Sensitivity: 25-50 pg (aromatics); 50-200 pg (olefins)
Gases: Makeup - same as the carrier gas
Temperature: 200°C

7. Electrolytic Conductivity Detector (ELCD)
Mechanism:
• Compounds are mixed with a reaction gas and passed through a high temperature reaction tube.
Specific reaction products are created which mix with a solvent and pass through an electrolytic
conductivity cell. The change in the electrolytic conductivity of the solvent is measured and a
signal is generated. Reaction tube temperature and solvent determine which types of compounds
are detected.
• Selectivity: Halogens, sulfur or nitrogen containing compounds.
Only one at a time.
• Sensitivity: 5-10 pg (halogens); 10-20 pg (S); 10-20 pg (N)
Linear range: 105 -106 (halogens); 104 -105 (N); 103.5-104(S)
Gases: Hydrogen (halogens and nitrogen); air (sulfur)
Temperature: 800-1000°C (halogens), 850-925°C (N), 750-825°C (S)

8. Mass Detector (MS)
Mechanism:
• Compounds are bombarded with electrons (EI) or gas molecules (CI). then fragmented into characteristic
charged ions or fragments. The resulting ions are focused and accelerated into a mass filter. mass filter
selectively allows all ions of a specific mass to pass through to the electron multiplier. All of the ions of the
specific mass are detected. The mass filter then allows the next mass to pass through while excluding all
others. The mass filter scans stepwise through the designated range of masses several times per second.
The total number of ions are counted for each scan. The abundance or number of ions per scan is plotted
versus time to obtain the chromatogram (called the TIC). A mass spectrum is obtained for each scan which
plots the various ion masses versus their abundance or number.
• Selectivity: compound gives fragments within mass range.
• Sensitivity: 1-10 ng (full scan); 1-10 pg (SIM)
Gases: None
Temperature: 250-300°C (transfer line), 150-250°C (source)

Good Detector
1. High sensitivity.
2. Rapidly respond to concentration changes.
3. Large linear range.
4. Stable with respect to noise and drift.
5. Low sensitivity to variation in flow,
6. Pressure and temperature.
7. Possible selectivity.
8. Produces an easily handled signal.
9. A temperature range from room temperature to at
least 400 C.

5. Carrier gas
An inert gas, which is used to sweep a mixture to
be separated through a gas chromatograph ,
(helium, hydrogen, or nitrogen).
• Push the sample through the gas
chromatograph column.
• Clean out the gas chromatograph column after
sample analysis.

Carrier Gas Control
The Flow mode has four options for the carrier
gas control:
• Constant flow
• Constant pressure
• Programmed flow
• Programmed pressure
The electronic control of the carrier gas allows
also the following operations.
• Column Evaluation
• Gas Saver Function
• Leak Check

Gas Purity
• All pure gases are classified by grade, so
you can be certain of purity levels.
• The first digit of the classification indicates
the number of nines purity (for example,
5.0 = 99.999% purity).
• The second digit is the number following
the last nine (for example 4.7 helium has a
guaranteed minimum purity of 99.997%
and a corresponding maximum impurity
level of 0.003% or 30ppm).

Carrier
The carrier gas
• Ultra-pure and research-grade gases of up to 99.9999%
(Grade 6.0) purity.
• The carrier gas system often contains a molecular sieve to
remove water or other impurities.
Linear Velocity (u)
• Is the speed at which the carrier gas or mobile phase
travels through the column.
• The linear velocity is generally expressed in cm/s.
• The linear velocity is independent of the column diameter
while the flow rate is dependent on the column diameter.

Required Gases Purities
Helium For carrier gas: 99.995%1 high purity, with less than 1.0 ppm each of
• water, oxygen, and total hydrocarbons after purification.
• Use water, oxygen, and hydrocarbon traps.
Hydrogen For carrier or detector fuel gas: 99.995%1 high purity, with <
• 1.0 ppm of total hydrocarbons after purification.
• Use water, oxygen and hydrocarbon traps.
Air For detector fuel gas: 99.995%1 high purity.
• Air compressors are not acceptable because they do not
• meet pressure, water, and hydrocarbon requirements.
Nitrogen For carrier or make-up gas: 99.995% high purity, with less than 1.0
• ppm of total hydrocarbons after purification.
Argon 5% Methane For ECD make-up gas: 99.995%1 high purity.

Leak Detection
CAUTION
• Do not use liquid soap leak detectors to
check for leaks. Liquid soap leak detectors
may contaminate you system.
• A mixture of 50% H2O/50% methanol or
isopropyl
• Alcohol may be used as a liquid leak
detector.
• WARNING! Never use liquid leak detectors
on or around electronic pneumatic circuits

Generators
Nitrogen Generator
• The nitrogen generator can also operate directly from the
laboratory compressed air supply.
• General contaminants are first removed with appropriate filters and
adsorbents and the purified air passes over layers of polymeric
hollow fiber membranes through which nitrogen selectively
permeates.
Hydrogen Generator
• In the Packard Hydrogen Generator, hydrogen is generated
electrolytically from pure deionized water.
• The electrolysis unit uses a solid polymer electrolyte and thus does
not need to be supplied with electrolytes, only the deionized water.

Hydrogen
• Hydrogen is a colorless, odorless, highly flammable
gas with the molecular formula H2 and an atomic
weight of 1.00794, making it the lightest element.
• Hydrogen is potentially explosive and must be used
with extreme care.
• Hydrogen is a dangerous gas that, when mixed with
air, could create an explosive mixture.
• Hydrogen is a dangerous gas, particularly in an
enclosed area when it reaches a concentration
corresponding to its lower explosion level (4% in
volume).

Chromatogram
The data recorder plots the signal from the detector over time.
• The retention time, is qualitatively indicative of the type of compound.
• The area under the peaks or the height of the peak is indicative of the amount of each
component

Retention Time (RT)
• RT, is the time it takes for a compound to travel
from the injection port to the detector.
• Thousands of chemicals may have the same
retention time, peak shape, and detector
response.
• For example, under certain conditions, DDT has
the same retention time as PCBs
(polychlorinated biphenyls).

Retention Time Shifts
• Different column temperature.
• Different carrier gas flow rate or linear velocity.
• Leak in the injector, especially the septum.
• Contaminated column.
• Change in the sample solvent.

Simple Checks
1. Gases - pressures, carrier gas average linear velocity,
2. and flow rates (detector, split vent, septum purge).
3. Temperatures - column, injector, detector .
4. System parameters - purge activation times, detector attenuation,
mass ranges, etc.
5. Gas lines and traps - cleanliness, leaks, expiration.
6. Injector consumables - septa, liners, O-rings and ferrules.
7. Sample integrity - concentration, degradation, solvent, storage.
8. Syringes - handling technique, leaks, needle sharpness, cleanliness.
9. Data system - settings and connections.

Troubleshooting categories
1. Baseline disturbances.
2. Irregular peak shapes or sizes.
3. Retention time shifts.
4. Loss of separation or resolution.
5. Quantitation difficulties.
6. Rapid column deteriorations.
7. Ghost peaks .
8. Broad solvent fronts.

Troubleshooting Tools
1. An electronic leak detector
2. A flow meter
3. An accurate thermometer
4. A reliable analytical column
5. New syringes
6. Spare septa and high temperature septa
7. Spare ferrules
8. Detector cleaning solutions
9. Spare recorder and electrometer cables
10. Instrument manuals

Environmental
What is the environmental market?
• Testing or commercial laboratories
• Industrial laboratories
• Government laboratories
• Research institutes
Requirements of the applications
• Drinking water
• High sensitivity Waste
• Sensitivity and selectivity Air
• Sample introduction

Clean water analysis
Pollutants in water
• Halocarbons
• Acid priority pollutants: phenols,
chlorophenols, nitrophenols
• Pesticides and PCBs
• Base neutral priority pollutants
• Polynuclear aromatic hydrocarbons

Petrochemical and Gas
Large replacement business
• Refinery
• Oil Industry
• Gas suppliers
• Multi-valves applications
• Fastest possible cycle time
• QC of gases: sensitivity
• Customized software
• Easy to use data handling and reporting

Food & Beverages
• Very extended market field
• No really regulated methods
• Ideal market to exploit the TRACE GC
modularity
• QC of producers: Sensitivity and rapidity
• Multi detection capability
• Correct sample inlet (PTV-OC)
• Easy to use data handling and reporting

Pharmaceutical
• Highly regulated market (pharmacopeia)
• Requires Validation package
• Requirements of the applications
• Limited instrument requirements
SSL/NPD/FID
• Highly Automated market
• High sensitivity detectors
• A unified chromatography software

Gas chromatography GC

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