APPLICATIONS OF GAS CHROMATOGRAPHY (GC

APPLICATIONS OF
GAS CHROMATOGRAPHY (GC)
Prof. Dr. P. Ravi Sankar, M.Pharm .,Ph. D
B. Sindhura M. Pharm
Vignan Pharmacy college
Vadlamudi
Guntur Dist.
Andhra Pradesh
India.
banuman35@gmail.com
+919000199106

APPLICATIONS OF GAS
CHROMATOGRAPHY
 Gas chromatography (gc) is an instrumental technique used forensically in
drug analysis, arson, toxicology analyses of other organic compounds.
 The gc is one of popular instrument used in the world several (applications)
advantages include:
1) High speed analysis in a matter of minutes and routine and less few
analysis in a matter of few seconds also possible and we see also both
rapid analysis as well as high sensitivity.
 For example is a 21/2 min of separation three common pesticides like
methyl parathion, malathion, ethion at pg levels. pg means 10-12 grams
these are parts per billion. this is very good example of both the high speed
as well as a very sensitive detection.

.
O2N O
P
S
O
O
CH3
CH3
S
P
S
O
O
H3C
H3C
O O
O
O
S
P
S
O
O
CH3
CH3
S
P
S
O
O
Methyl parathion
Melathion
Ethion

USES: Petroleum products, waxes, solvents, hydrocarbons, highly volatile solvents.

COMMON APPLICATIONS:
• Quantification of pollutants in drinking and waste water using official U.S.
Environmental Protection Agency (EPA) methods.
• Quantification of drugs and their metabolites in blood and urine for both
pharmacological and forensic applications.
• Identification of unknown organic compounds in hazardous waste dumps.
• Identification of reaction products.
• Analysis of industrial products for quality control.
ANALYSIS OF VOLATILE ORGANIC COMPOUNDS IN INDOOR AIR

• Gas chromatography is a physical separation method in where volatile
mixtures are separated. It can be used in many different fields such as
pharmaceuticals, cosmetics and even environmental toxins. Since the
samples have to be volatile, human breathe, blood, saliva and other secretions
containing large amounts of organic volatiles can be easily analyzed using
GC. Knowing the amount of which compound is in a given sample gives a
huge advantage in studying the effects of human health and of the
environment as well.
• Air samples can be analyzed using GC. Most of the time, air quality control
units use GC coupled with FID in order to determine the components of a
given air sample. Although other detectors are useful as well, FID is the most
appropriate because of its sensitivity and resolution and also because it can
detect very small molecules as well.
• GC/MS is also another useful method which can determine the components
of a given mixture using the retention times and the abundance of the
samples. This method be applied to many pharmaceutical applications such
as identifying the amount of chemicals in drugs. Moreover, cosmetic
manufacturers also use this method to effectively measure how much of each
chemical is used for their products.

• GC and liquid chromatography together just been the
premier technique for trace analysis of organic and
inorganic compounds.
• If I think all the work which is been done in air
pollution and water pollution and food safety.
• we have to analyze pesticides toxic chemicals founds
in food and food products
• We have to analyze the pesticide and food safety and
toxic chemicals and food Products and all of these
things are daily and rapidly by GC and or liquid
chromatography.

Chemical analysis
GC Analysis of Xylene Isomers on SLB®-IL60
application for GC
The xylene isomers are precursors to many chemicals:
• o-xylene is a precursor for phthalic anhydride
• m-xylene is a precursor for isophthalic acid
• p-xylene is a precursor for terephthalic acid and dimethyl terephthalate
The cresol (methyl phenol) isomers are also precursors to many chemicals. This
chromatogram of a mix of aromatic and methyl phenol compounds was
generated using an SLB-IL60 ionic liquid column. Its interaction mechanisms
allow the separation of all three xylene isomers, and all three cresol isomers.

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Guard Columns/Retention Gaps, Capillary GC Columns, by industry / application,
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test parameters column: SLB-IL60, 30 m x 0.25 mm I.D., 0.20 μm (29505-U)
oven: 40 °C (4 min), 8 °C/min to 200 °C (5 min)
inj. temp.: 250 °C
detector: FID, 250 °C
carrier gas: 30 cm/sec constant pressure
injection: 1 μL100:1 split
liner: 4 mm I.D., split/splitless type, wool packed single taper FocusLiner™ design
sample: 12 analytes, each at 0.2% (v/v) in pentane
suitability application for GC
Featured
Industry
Chemicals and Industrial Polymers

Peak formation of xylene isomers:

Separation of m - and p - Xylenes by Gas
Chromatography on Dimethyl Polysiloxone.
Short piece of 5% diphenyl 95% dimethyl
column connected to a wax column.
Cryofocusing was done on the 5
(which still has some diffusivity at -
80°C) and rapid heating to 40°C
restored the wax to a “liquid” to allow
the efficient separation of m- and p-
xylenes. A wax is one of the only
commercially-available capillary GC
stationary phases that will separate m-
and p- xylenes.

Analysis of p-Xylene by GC-FID using a
HP-INNO Wax column
The purity of solutions, from relatively pure
solvent such as xylene, to liquors such as
scotch can be also be determined by GC.
Two examples are shown below.
Analysis of Minor Components of Scotch by
GC-FID using a HP-101 Column

 One of the aspects of my job that I really enjoy is explaining the
science of Blood Alcohol Concentration and/or reported levels of
Drugs of Abuse to normal everyday folks, judges, jurors,
prosecutors and even fellow attorneys.
 One of the most common questions I get asked is in the area of gas
chromatography. Just yesterday a colleague from Texas called me
up to help him interpret a Gas Chromatography result. He asked:
1. How do they make the squiggly lines [of a chromatogram] turn
into a magic number [the reported BAC]?
2. It’s a great question. In essence, how do we take the electrical
signal output from the detector and resolve that raw data into
reported quantified result for our analyse of interest?
 In chromatography and in particular when a Flame Ionization
Detector is used as the quantifying device, the method that we use
to arrive the ultimate reported result is a product of the peak of the
chromatogram. The peak height, the peak shape and the peak area
are important.

Petroleum product analysis
GC Analysis of Small Molecules in Jet Fuel on Supel-Q™ PLOT
application for GC
Properties
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test parameters column: Supel-Q PLOT
oven: 35 °C (3 min), 16 °C/min to 250 °C
detector: TCD
carrier gas: helium, 3.0 mL/min
sample: Jet fuel
Featured Industry Petroleum

GC Analysis of Water in Gasoline on Supel-Q™ PLOT
application for GC
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Capillary GC Columns, by name, Chromatograms, Compound Class, GC
Applications, GC Columns for the Petroleum Industry, Gas Chromatography
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PLOT
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test parameters column: Supel-Q
detector: TCD
carrier gas: helium, 3.0 mL/min
sample: Gasoline
Featured Industry Petroleum

One advantages of adsorption ( GC) chromatography,
as is also true for GSC, is that it is able to retain and
separate some compounds that can not be separated
by other methods. One such application is in the
separation of geometrical isomers.

 Primary column: Fused silica 30m by 0.25 mm ID. 5% diphenyl, 95% dimethyl
polysiloxone stationary phase having 0.25 micrometer film thickness.
 Secondary column: Fused silica 30m by 0.25mm ID internally coated with 14%
cyanopropyl phenyl and 86% dimethyl polysiloxone stationary phase having
0.25 µm film thickness.
 The role of modulator is to collect fractions from chromatographic technique. It
employs 2 columns in series separated by a modulator.
 The role of modulator is to collect the fractions from first column often called
as First dimension column or Primary column or 1o column and then focus on
to the Secondary column or 20 column.
 Primary column tend to be 30m X 0.25mm ID.
 Secondary column tend to be 1-2m X 0.10mm ID.

DETERMINATION OF PESTICIDES RESIDUE IN
AQUACULTURE PRODUCTS
DETECTION AND QUANTITATION BY GAS CHROMATOGRAPHY
 Agricultural chemicals such as fertilizers and pesticides
have made an important contribution to agriculture.
 Pesticides protect crops from pests and diseases. They have brought about large yield
increases. Since almost all chemicals that can kill pests are also potentially damaging to
human health.
 Legislation requires that pesticide use
is appropriately controlled and maximum
residue levels (MRL) not be exceeded.
 Detection method is the process of identifying
the pesticides and determining their concentrations
with the aid of an analytical instrument, such as a
gas chromatograph (GC), we can obtain
information about the original sample
by running a standard solution containing
the pesticide(s) at a known concentration and comparing it with the sample.

GC Analysis of Pesticides in Grapes on SLB®-5ms after QuEChERS
Cleanup using Supel™ QuE PSA/C18
application for GC, application for SPE

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GC column, by industry/applications.
Test parameters Sample preparation : dispersive (QuEChERS).
Sample/matrix : Thomson green seedless table grapes.
extraction tube : supel QuE Acetate extraction tubes (55234-U).
extraction process : add 15 ml of acetonitrile with 1% acetic acid; shake for 1 min; add contents of
supel QuE acetate extraction tubes; shake at 2500 rpm for 10 min.
clean-up tubes: supel QuE PSA/C18 suitable for 2007.01 per AOAC(55288-U).
Clean up process : transfer 1ml of acetonitrile layer into cleanup tube; shake for 1 min ; centrifuge at
5000 rpm for 3 min; draw off supernatant for LVI-GC/MS analysis.
Column : SLB-5ms, 20*0.18µm(28564-U).
Oven : 50֯c (2.9 min), 8֯C/min to 330֯C.
Inj. temp : programed 50֯C (0.4min), 600֯C/min to325֯C (5min).
Detector :MS-SIM.
MSD interface : 330֯C.
Scan range : SIM.
Carrier gas : helium, 0.7 mL/min constant flow.
injection: 10 μL PTV; 100 mL/min vent flow (5 psi) until 0.4 min, purge flow to split vent 60 mL/min
at 2.9 min.
liner: 4 mm ID Focus Liner w/taper .
Suitability . Application for GC.
Application for SPE.
Featured
industry.
Agriculture
Food and Beverages

GAS CHROMATOGRAPHIC CONDITIONS
 Gas chromatograph Model: Shimadzu GC-17A, equipped with 63 Nielectron
capture detector, attached to a CBM-102 Chromatopak recorder system.
 Detector: Electron capture detector (ECD)
 Column: SPB-608 (Supelco), Capillary (Fused silica), 30m X 0.25mm I.D.,
0.25 um film
 Column Oven Temperature: 150°C (4 min) to 290°C at 8o C/min, hold 10
min.
 Detector temperature: 300oC
 Injector temperature: 220o C
 Carrier gas: Nitrogen (N2) at f low rate of 40 cm/sec.
Measure the area or height of residue peak(s) and determine the residue amount by
comparison to peak area or height obtained from a known amount of appropriate
reference material(s).

 Determination of the VOCs toluene , ethylbenzene, o-xylene
and cumene (TEXC) in air analysed and quantified using a
gas chromatograph with flame ionisation detection (GC-FID).
 Volatile organic compounds (VOCs) are a cause of concern
for human health due to their increased presence in the indoor
environment.
 They are responsible for a phenomenon known as the sick
building syndrome (SBS). Air monitoring is being used to
assess indoor pollution.

 The pharmaceutical industry also heavily uses GC and HPLC to determine the
purity of reagents, the identity of synthesis products, and the identity of medicines
and illicit drugs. A few examples are shown below:
 In most forensic applications of GC, a sample is prepared by dissolving it in a
solvent, and the solution is injected into the instrument using a syringe. For
example, to analyse a white powder suspected of being cocaine, a small portion is
weighed out and dissolved in a solvent such as methylene chloride, methanol, or
chloroform.
 A tiny portion of the sample is then drawn up into a syringe and injected into the
heated injector port of the instrument. The mobile phase gas (called the carrier gas)
also enters the injector port, picking up the volatilized sample and introducing it into
the column where the separation process occurs.
 If the sample contains cocaine, it will emerge from the column at a given time
(known as the retention time) that can be compared to the retention time of a known
standard sample of cocaine. The retention time in conjunction with information
obtained from the detector is used to positively identify the compound as cocaine if
indeed it is present.
 Another method of sample introduction for GC is called pyrolysis, in which a solid
sample such as a fiber or paint chip is heated in a special sample holder to extreme
temperatures, causing the sample to decompose into gaseous components that can
then be introduced into the GC.
 Pyrolysis is used when the sample is not readily soluble in common GC solvents.

GC-MS USED IN THYROID
CANCER STUDY
 Gas chromatography-Mass spectrometry (GC-MS) has been used to
investigate the pathogenic differences in a form of cancer according
to gender and menopausal condition.
 In a study published by BMC(biomed central services publish
original research on oncology). Cancer, scientists sought to evaluate
the metabolic changes in urinary steroids in men and pre and post-
menopausal women with papillary thyroid carcinoma (PTC).
 GC-MS was used to measure the urinary concentrations of 84
steroids in all of the patients against corresponding controls.
 The metabolic ratio of 2-hydroxy estrone to 2-hydroxy-17 beta-
estradiol in particular showed gender differences in PTC patients.
 It is hoped the findings could help better understand the pathogenic
differences in PTC according to gender and menopausal conditions.

o Gas chromatography (GC) is the most common method for analysing
phytosterol content and composition . There are HPLC methods available
for separating and quantifying the various forms of phytosterols, such as
free sterols, steryl fatty acid esters, steryl glycosides, acylated steryl
glycosides, and hydroxycinnamic acid esters of sterols [1,10].
o However, with over 200 different structures, GC, often combined with
mass spectrometry, is the best and most widely used tool for the
chromatographic separation, identification, and quantification of
phytosterol qualitative and quantitative analysis of phytosterols in food
products.
o Therefore, GC-mass spectrometry (GC-MS) is a valuable aid for
identifying unknown phytosterol peaks as well as for confirming the
identification and purity of identified phytosterol peaks are identified
using flame-ionization detection (FID) by comparing the retention times
(RT) of sterol peaks to that of pure standards.
o A few sterol standards including cholesterol and cholesterol derivatives
and analogues, campesterol, campestanol, stigmasterol, sitosterol,
sitostanol, brassicasterol, fucosterol, cycloartenol, and ergosterol are
available from commercial vendors such as Sigma,

 Plant sterols (phytosterols) are ubiquitous in plants
 The most common phytosterols have a double bond at
position 5 of the B-ring, (commonly referred to as Δ5),
however, Δ7-phytosterols are also found in many seed oils,
while cereals such as corn, wheat, rice, rye
 Phytosterols are well-known for their ability to lower blood
cholesterol by competing with absorption of cholesterol from
the diet and reabsorption of bile cholesterol

2. High resolution:
 Many compounds can be resolved nicely.
 For ex: gasoline has been resolved in to over 300 different peaks
complex sample of Petroleum
Oil refinery – separates fractions of oil
for petroleum products.

Natural Gas
• GC can also be used to determine the
identity of natural products containing
complex mixtures of similar
compounds.
• For example, the geographic source
of crude oil or natural gas can be
determined by the “fingerprint”, or
relative distribution of major and
trace compounds in each oil.
• Natural produce oils, such as food
products or fragrances, can be
identified by GC-FID or GC-MS.
• A few examples of the separation of
these complex mixtures are shown
below.

 Barbiturates are a class of compounds that are central nervous
system depressants. They are categorized as sedatives or
hypnotics and are primarily used in the treatment of anxiety,
insomnia, and convulsive disorders.
 Barbiturates can be analysed in either their underivatized or
derivatized forms by gas chromatography. Derivatization of the
barbiturates is most commonly performed by methylation of the
amido nitrogens in positions 1 and 3. Methylating reagents like
tetramethylammonium hydroxide (TMAH) and
trimethylanilinium anilinium hydroxide (TMPAH) can be used.
 Analysis of barbiturates can also be performed on underivatized
compounds.
 However, underivatized barbiturates have a tendency to produce
overloaded or tailing peaks. Maintain injection port liners, guard
columns, and analytical columns regularly to achieve good peak
shape and adequate resolution.

Analysis of Anticonvulsants by GC-FID using an
HP-1 column. Source: Agilent Technologies.

BARBITURATE ENANTIOMERS APPLICATION FOR GC:
One enantiomer in the mixture may have an activity or toxicity ...
Out of the many chiral complexing agents used to separate chiral
drugs by gas chromatography (GC).
Description
(±)-Mephobarbital
Hexobarbital
carrier gas : helium, 20 cm/sec @ 275 °C
column : β-DEX 120, 30 m × 0.25 mm I.D., 0.25 μm (24304)
det. : FID, 300 °C
inj. : 300 °C
injection : 100:1 split
oven : 210 °C

ANALYSIS OF ALKALOIDS AND BARBITURATES BY GC-FID
WITH AN ULTRA 2 COLUMN.

ANALYSIS OF PEPPERMINT OIL BY GC-FID USING AN HP-INNO WAX
COLUMN

Chlordiazepoxide is a long acting benzodiazepine drug.
The half-life of Chlordiazepoxide is 5 – 30 hours but has
an active benzodiazepine metabolite
(desmethyldiazepam) which has a half-life of 36 – 200
hours.
A rapid gas chromatographic method for the
determination of diazepam and metabolites in body
fluids. A rapid method is described for the extraction of
diazepam and its metabolites from plasma and urine. The
procedure is applicable to subsequent analysis by electron
capture gas chromatography, and has been used for the
analysis of clinical samples. The detection limit for
diazepam is about 0.01 μg/ml.

NOVELAPPLICATIONS IN GAS CHROMATOGRAPHY
DETECTION OF ARSON ACCELERANTS USING GAS
CHROMATOGRAPHY
Arson studies:
 Gas chromatography – mass spectrometry (GC/MS)
is a well established method for analysis
of ignitable liquids.
 According to the US Fire Administration, arson
is the leading cause of fires and the second leading
cause of deaths and injures, and that’s why arson
investigation is of forensic significance for the
criminal justice system.
 Commercially available fuels or solvents that
are mixtures consisting of hundreds of components are
typically used to start a fire.
 Analysis becomes very difficult because ignitable liquids consist of same or
similar components at different concentrations, in addition, fire may evaporate
some of the components and thus altering the composition of residual ignitable
liquids found in fire debris.
 Analysis, detection, and identification of accelerants in arson studies are indeed
applicable in gas chromatography.

BLOOD ALCOHOLS (PACKED APPLICATION GC)
 The determination (accurately measure)of blood alcohol content (BAC) is one of the most
common tests performed by forensic laboratories.
 Blood alcohol analysis is used by law enforcement to determine if a driver was unlawfully
operating a vehicle. The results will be used in a court of law, therefore it is important to
minimize systematic and operator errors.
 This application note presents the details of an optimized column separation method for the
determination of ethyl alcohol, the internal standard propyl alcohol, three other common
alcohols, and many potentially interfering common volatiles present in samples being
analysed for measures of driving under the influence of alcohol" (DUI )acronym used in
many regulating districts).
 This possible method for determining forensic blood alcohol concentrations.
carrier gas : helium, 20 mL/min.
column : 6 ft. × 2 mm I.D. glass
det. : FID
injection : 1 μL
oven : 85 °C
packing : 5% Carbowax 20M on 60/80 Carbopack B
 Determination of alcohol (i.e. ethanol) in blood or urine. One obvious application is when
law enforcement agencies need to determine whether or not someone is inebriated. In these
cases, high sensitivity is required since 0.1% blood alcohol content is considered to be
legally intoxicated in most states.

 We take the area under the peak, then apply that numeric to the calibration
curve to arrive at the reported result.
 The peak shape should be Poisson, Gaussian or close to Gaussian.
[Blogger’s note: in Wednesday’s post we will describe what consequences
can occur if it is not]
 A calibration curve is simply a graph where concentration is plotted along
the x-axis and area is plotted along the y-axis. [See the previous post about
calibration curves-When is a straight line a curve: Calibration curve]
 Figure 2 is an example of a calibration curve for a hypothetical compound
X. It was created by running 5 different calibration standards (5, 10, 15, 20,
25 g/mL). Each concentration gave a peak area (5000, 10000, 15000,
20000, 25000). Peak area was then plotted against the concentrations.
 Once we have constructed our curve, we can analyse our sample. We
simply determine the peak area for the analyses in our sample, and then
draw a line on the graph at that area (note the red arrows). When the
calibration curve is reached, we drop a line down to the x-axis. That will
give us the concentration of the analyses in our sample. This is why the
area under the peak and peak shape is important in gas chromatography.

GC Analysis of Blood Alcohols in Human Plasma on SUPELCOWAX® 10 after
SPME using 60 μm Carbowax® Fiber
application for GC, application for SPME

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Alcohols, Analytical/Chromatography, Applications, Blood Alcohols, Capillary GC
Columns and Guard Columns/Retention Gaps,
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Bioanalytical, Compound Class, Drugs & Pharmaceuticals, Drugs of Abuse, GC
Applications, GC Columns for the Forensic Industry, Gas Chromatography (GC), Polar
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Less...
test parameters sample/matrix: blood alcohols at concentrations indicated in human plasma
SPME fiber: 60 μm Carbowax
extraction: headspace, 50 °C (5 min)
desorption process: 220 °C, 2 min
column: SUPELCOWAX 10, 30 m × 0.25 mm I.D., 0.50 μm (24284)
carrier gas: helium, 1.0 mL/min constant
injection: 10:1 split
liner: 0.75 mm I.D. SPME liner
application for SPME
Featured Industry Forensics and Toxicology
Properties

RAPID METHOD FOR DETERMINATION OF ETHANOL IN
ALCOHOLIC
BEVERAGES USING CAPILLARY GAS CHROMATOGRAPHY
 Ethanol content is very important for the mouth-feel and flavour of
alcoholic beverages. Ethanol contents of wine, liqueur, and beer
range from 7~21%(v/v), 20~50%(v/v), and 3~6%(v/v), respectively
(1). In general, ethanol contents serve as the quality index and
taxation factor for alcoholic beverages(2). After entering WTO,
alcoholic beverages in Taiwan are taxed according to the ethanol
contents, like the taxation system in United States(3).
 The higher the ethanol content in an alcoholic beverage, the higher
the tax. It takes only 7~8 min to complete a sample analysis for the
determination of ethanol content in a beverage sample. A sample
solution (0.5 mL) is mixed with adequate amount (5 mL) of 1%
(w/v) internal standard solution (acetonitrile, equivalent to 50 mg),
and injected into a capillary GC.

BREATH ALCOHOL TESTING
Drunk driving costs countless lives and destroys families around the
world each year. In most countries drunk driving is illegal and in
pursuing these laws the police utilizes breathalysers tests.
Test equipment must be perfectly calibrated to stand up in a court of
law. Therefore one of the calibration methods is to use a calibration
gas. The demands on such a calibration gas are strict, it must be easy
to use, be stable, portable and fool-proof. Linde produces and
delivers such calibration gases with the breathable program.
Determination of free cholesterol in milk fat: rapid and direct gas
chromatographic (GC) method for determining free cholesterol in
milk fat using a capillary column and programmed-temperature
vaporizer injector was assayed.
Soil and Water Measurement contamination of soil and water can
come from many areas, including acid rain, pesticides industrial
waste, landfill, and raw sewage. Analytical procedures include
GC/MS.

 Environmental measurement is accomplished in many ways. Air
samples may be collected using sample bags or containers and
analysed using gas chromatography. For example, with the US EPA
CEMS have a requirement under some environmental regulations for
either continuous compliance determination of the level in which the
facility is out of compliance with acceptable emission standards. In all
areas, a variety of pure gases and calibration gas mixtures are
required. Additionally, due to legal requirements, many of these gas
mixtures will need to be accredited to international standards.
Air Quality Monitoring
 International accords such as the Montreal protocol, or Kyoto accords
call on all industry everywhere to monitor, control and reduce their
emissions before discharging them into the environment.
 There are a number of different particulate and gaseous emissions
which result from smoke stack emissions in many industries
including manufacturing, chemical and petrochemical, and power
generation.

AREAS OF KEY MEASUREMENT INCLUDE
 Carbon monoxide (CO) from industrial processes and
incomplete combustion of wood, oil, gas and coal.
 Carbon dioxide (CO2) , Sulphur Dioxide (SO2), and Nitric
oxides (NO and NO2) from combustion of gas, oil and coal.
 Hydrogen sulphide (H2S) and methyl mercaptan (CH3SH)
from pulp and paper mills.
 Hydrocarbons resulting from incomplete combustion of fuels.
 ISO 3930 requirements for vehicle exhaust emission levels for
carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons
(HC, in terms of n-hexane), and oxygen (O2).
 In all areas, a variety of environmental pure
gases and calibration gas standards are required.
 Additionally, due to legislative, and/or legal requirements,
many of these standards will need which need manufacturing
to accreditation levels.

FOOD PACKAGING
 Modified Atmosphere Packaging of food, or MAP, is a natural
shelf-life-enhancing method that is growing rapidly on an
international scale. It often complements other techniques, such
as high-pressure and microwave methods or oxygen absorption.
 The correct gas mixture in MAP maintains high quality by
retaining the original taste, texture and appearance of the
foodstuff.
 On the other hand, should the product have a high fat content and
low water activity, oxidation protection is most important and
inert nitrogen would be the preferred choice.
 The gas atmosphere must be chosen with due consideration of
the particular foodstuff and its properties. For low-fat products
with a high moisture content, it is especially the growth of
microorganism that has to be inhibited by using carbon dioxide

Food and beverages applications
 Foods and beverages contain numerous aromatic compounds,
some naturally present in the raw materials and some forming
during processing.
 GC is extensively used for the analysis of these compounds
which include esters, fatty acids, alcohols, aldehydes, terpenes
etc.
 It is also used to detect and measure contaminants from spoilage
or adulteration which may be harmful and which is often
controlled by governmental agencies, for example pesticides.

GC Analysis of Organic Acids on Nukol™ application for GC

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test
parameters
column: Nukol, 15 m x 0.32 mm I.D., 0.25 μm (24130)
inj. temp.: 250 °C
carrier gas: helium, 2 mL/min constant
injection: 1 μL100:1 split
liner: 4 mm I.D., split, cup design
sample: 5 analytes, at concentrations indicated in 1 M Phosphoric acid
Featured
Industry
Food and Beverages
Properties

LASER CUTTING & WELDING
 Linde technology is being used constantly the world over in laser
applications – in manufacturing, metallurgy, chemicals, food processing,
medicine, alternative fuel technologies & environmental technology. The
LASERLINE® concept of high purity gas products and comprehensive
services, applications know-how along with cost efficient gas supply
options forms the basis for customised solutions that maximise
productivity
Leak Testing
 Producing tight systems is necessary, no matter if you produce tanks for
the space shuttle, automotive gas tanks or gas distribution systems. Other
typical leak test objects are air bags and pace makers, and anyone can
understand what a disaster these could cause if not tight.
 Leak testing is often done with a gas or gas mixture together with a
"sniffer" which is a specialized mass spectrometer (MS). Gas tanks
and distribution systems are checked with helium or helium mixtures
while automotive systems often are checked with sulphur hexafluoride

For trace evidence, the ability to get the most information from the smallest sample provided, while preserving the maximum
amount for other tests, is critical in delivering results to solve crimes.
Gas chromatography mass spectrometry (GC/MS) is an important technique in the detection
and identification of both bulk drugs and trace level drugs in biological samples. The
PerkinElmer® Clarus® 600 GC/MS is a highly-sensitive and robust system with flexibility
to accommodate the wide range of analyses typical to drug investigations.
DRUGS-OF-ABUSE ANALYSIS BY
GC/MS

RAPID ANALYSIS OF PESTICIDE
RESIDUES IN GREEN BEANS:
Pesticide analysis is extremely important due to the need to
ensure that foodstuff is not contaminated with pesticide
residues, which can be harmful to human health. Pesticide
analysis poses a number of challenges for laboratories due to
the wide ranging chemistries within the contaminants.
Scientists have used gas chromatography-mass
spectrometry (GC-MS) to obtain samples in order to
construct an in-depth human glomerulus proteome database.
They hope the database will help increase the understanding
of renal disease pathogenesis, as well aiding biomarker
exploration.

GAS CHROMATOGRAPHY-MASS SPECTROMETRY USED
TO LOOK AT ALTERNATIVE INSECTICIDES FOR CONTROL
OF MALARIA
 Gas chromatography-mass spectrometry has been used to
look into the insecticidal activity of the essential oils in
fruits and seeds taken from Schinus terebinth
folia Raddiagainst Africa malaria and filarial vectors.
Reported in the Parasites & Vectors journal, research
assessed the plant oil against Anopheles gambiae s.s,
An.arabiensis and Culex quinquefasciatus.
 The twenty third instar larvae of the anopheles
gambiaes.s and Cx. quinquefasciatus were exposed to
different dosages of the oil, with mortality rates being
observed at 12, 24, 48 and 72 hours.

Barbiturates and benzodiazepines are usually encountered by the
forensic scientist as tablet or capsule preparations that have been
diverted from licit sources, or, particularly in the case of barbiturates,
as ‘cutting agents’ in other drug materials (for example,
phenobarbitone in heroin samples).
In some cases, identification and confirmation of the dose form can
be achieved by using internationally available databases. If this is
not possible, then the traditional process of physical description,
presumptive testing, TLC and GC–MS should be followed to identify
the drug components.
However, some benzodiazepines are thermally labile and in such
cases HPLC, possibly with diode-array detection, is often the
chosen method of analysis.
The latter technique is, in addition, the preferred method for
quantification purposes.
Such drugs, when obtained from licit sources, are very pure and it is
therefore particularly difficult, if not impossible, to compare the
samples in order to determine if they once originated from the same
batch.

 Novel method for a rapid measurement of the volatile compounds of food a fruit
juice should not contain ethanol, but in some cases a fermentation can occur. The
maximum ethanol concentration allowed is 0.5% vol. We were asked to propose a
rapid method for the measurement of this ethanol content.
 The method was as follows: Apple juice (8ml) was placed in a 22ml vial and
ethanol was added in order to obtain a concentration of between 0.05 and 0.5%
vol. The sample was thermostatised at 30°C for 30min. The head-space was
sampled using a SPME- fiber, with an adsorption time of 2 min.
 The desorption took place in the TV9000 in 1 min. The signal was measured with
a FID. The Fig. 5 shows the correlation between the amount of ethanol added and
the area of the signal, for both standard ethanol solutions and spiked samples.
 The high area before any addition of ethanol (0 concentration) comes from the
volatile compounds of the apple juice. Using this method, we can determine the
concentration of ethanol in apple juice, and also monitor the evolution of ethanol
during the fermentation of apple juice.
Conclusion
The TV 9000 is...
Simple........
Robust........
Easy to use........

 ANALYSIS OF ANABOLIC STEROIDS FOR DOPING CONTROL PURPOSES BY GC
In this application note, the performance of both one dimensional GC-TOFMS and GC x GC-
TOFMS were evaluated, with special attention to the detectability and the confirmation reliability
at low ppb concentration. For this purpose, five anabolic steroids were selected, for which very
low detection limits (2 ng/mL) are required by the World Anti-Doping Agency.
 QUALITATIVE COMPARISON OF WHISKY SAMPLES USING FAST GC
In quality control of alcoholic beverages it is often important to compare different production
batches to detect possible changes in the fermentation and/or distillation process. This note
describes the application of a simple and fast GC method with MS detection using the Pegasus II
Time of-Flight GC/MS detector.
 THE APPLICATION OF GC/MS TO THE ANALYSIS OF PESTICIDES IN FOODSTUFFS
Pesticide contamination of foodstuffs has become a worldwide concern, prompting various levels
of regulation and monitoring. The discovery of the structure of insulin, for example, was made
possible when the British biochemist, Frederick Sanger, rationally and methodically applied the
technique to the fragments of the ruptured insulin molecule, for which he received the 1958 Nobel
prize for chemistry

Because of its simplicity, sensitivity, and effectiveness in separating
components of mixtures, gas chromatography is one of the most
important tools in chemistry. It is widely used for quantitative and
qualitative analysis of mixtures, for the purification of compounds,
and for the determination of such thermochemical constants as
heats of solution and vaporization, vapour pressure and activity
coefficients.
Gas chromatography is also used to monitor industrial processes
automatically: gas streams are analyzed periodically and manual or
automatic responses are made to counteract undesirable
variations. Many routine analyses are performed rapidly in
environmental and other fields.
For example, many countries have fixed monitor points to
continuously measure the emission levels of for instance nitrogen
dioxides, carbon dioxide and carbon monoxide.
Gas chromatography is also useful in the analysis of pharmaceutical
products, alcohol in blood, essential oils and food products.

• Gas chromatography is widely used for the separation and analysis of mixtures of
many compounds at very low concentrations .
• The compounds which has low boiling points lower than 300oC can be easily
analyzed by this Technique.
• The main areas of application of gas chromatography are
 Analysis of toxic compounds, solvents, hydrocarbons as well as in forensic field,
 Pollution studies, environmental analysis.
• Gas chromatography is mainly used in Pharmaceutical industry for the quantitative
as well as qualitative estimation of solid, liquid and gaseous organic compounds.
• This technique is preferred over spectrophotometry and titration because the
separation. As well as (both qualitative and quantitative can be carried out
simultaneously.
1.Qualitative analysis:
 Identification of the compound by GC either by following ways…
A. Collecting the eluted vapours from the column and subjecting them to specific
technique like Mass spectroscopy, I.R, U.V, NMR etc.
B. The retention time here is used for qualitative analysis. Qualitative analysis That is
to say what is that peak.
C. The retention time is simply a the time from the point of injection to the peak
Maximum. That is the characteristic of this column and this system these
conditions.

 If the sample under test and the standard compounds are same , then under identical
conditions their resolution time are also same. Any deviation of graph from the standard
Indicates the presence of a compound other than the standard.
Specific Retention volume of sample
o The relative retention R (sample/standard) =
Specific retention volume of standard
2. Quantitative analysis:
The next imp factor is the peak area. The peak area is
used for peak concentration. Twice the concentration
twice the peak Area.
This peak area represents the amount of sample which is
present in the Peak. One can also use peak height.
The world countries do not have computes often times
simple rulers used for measuring peak heights. But In the
modern world computers and integrates peak areas easily
obtained and the results printed out on the recorders.

Pharmaceutical applications : Chromatography plays imp. Role in the analysis of
pharmaceutical products and drugs.
1. Quality control and analysis of drug products an d in monitoring metabolites in biological Fluids.
Antibiotics
Penicillin's and its derivatives, Gentamycin, kanamycin ,
Neomycin , tetracycline, chloramphenicol, etc.
Anti T.B drugs Ethambutol, Isoniazid, Rifampicin.
Anti cancer drugs
6- mercaptopurin, fluorouracil, doxorubin, tamoxifen,
busulfan, thiotepa, melfalan, etc…
Antivirals Amantadine, cytarabin, Idoxuridine
CNS stimulants Caffeine, theophylline, Nikethamide
General anesthetics Chloroform, ether ,ethanol etc.
Sedatives/ hypnotics
Barbiturates, Guanidine, Phenobarbital (luminol),
Mephobarbital,
Benzodiazepines,
Tranquilizers( some
Major and minor tranquilizers)
Diazepam(Valium),Chlordiazepoxide
(Librium),Flurazepam
(Dalmane),Alprazolam(Xanax),Lorazepam
(Ativan),phenothiazine, identified and measured by GC
.etc.
Tri cyclic Antidepressants and its
metabolites.(TCA’s)
Imipramine, Desipramine, Imitriptyline, Nor triptyline

Drug Solid phase Liquid phase Mobile phase Detector
Atropine
sulphate
Acid washed
salinized
Diatomaceous
support.
3% w/w of coated with
phenyl methyl silicone
Fluid.
Nitrogen FID
Homatropine Same as above Same as above Nitrogen FID
Hyoscine
hydrobromidee
yeye drops.
Same as above Same as above Nitrogen FID
Clove oil same as above
3% w/w of
PEG.
Nitrogen FID
Ethosuximide
syrup
Same as above
3%w/w of
Cyanopropyl methyl
phenyl,
Silicone fluid.
Nitrogen FID
Steric acid Same as above
15% w/w of
Diethylene
Glycol
Succinate polyester.
Nitrogen FID

Ethyl
oestrenol
Glass column acid
washed salinized
diatomaceous
support.
Coated with 3%w/w
phenyl methyl silicone
fluid.
Nitrogen
FID
Econazole
nitrite cream
same
Coated with 3%w/w pf
phenyl methyl silicane fluid
glass column
Nitrogen FID
Chloroxyleno
l solution
Same Coated with 3% PEG
Nitrogen FID
Fenfluramine
Hcl tablets
Same
Coated with 10% PEG and
2% W/W of KOH. Nitrogen FID
Lincomycin
Hcl
Same
Coated with 3%W/W of
phenyl methyl silicone fluid Helium FID
Mianserin
HCl
Same
Coated with 3% W/W Phenyl
methyl silicone.
Nitrogen FID
Troxidone
caps.
Stainless steel
column packed with
porous polymer beads
Nitrogen FID

2. Isolation and identification of mixtures of plant extracts, carbohydrates, volatile oils, Amino
acids, lipids proteins, preservatives, vitamins, colorants, flavours etc.
3. Identification and determination of fatty acids. Determination of fate of the drugs in body
fluids like plasma, serum, urine. Etc.
4. Analysis of solvents, organic functional groups, natural fats ,alcoholic beverages etc.
5. Determination of protective coatings like styrene monomer, vinyl toluene, toluene
diisocyanate etc.
Miscellaneous Applications:
1. Gas chromatography is widely used in the analysis of fertilizers, rubber, cosmetics,
perfumes, food products and petroleum products.
2. For detection of steroids taken by athletes during international sports competitions.
3. IN environmental studies for the isolation and identification of chlorinated pesticides like
DDT and BHC, organ mercuric compounds, organophorous compounds, Sulphur
compounds etc.
4. For the analysis of dairy products like milk, butter, cheese, etc., for the presence of
aldehyde, ketones, milk sugars and fatty acids. Gas-liquid chromatography is applicable to
species with high critical temperatures and normal boiling points as high as 400° C.
5. Substances that are solids at normal laboratory conditions with molecular weights below
1,000 are best separated with liquid-solid or liquid-liquid systems.
6. Lower members of the molecular weight scale range are amenable to supercritical-
fluid separations. Size-exclusion methods are involved at molecular weights above 1,000.
7. Field-flow fractionation extends the size range to colloids and microscopic particles.

GC Analysis of Ibuprofen Enantiomers(Underivatized) on β-DEX™ 120
application for GC
Related
Categories
β-DEX 120, Active Pharmaceutical Ingredients (APIs),
Columns/Retention Gaps,
test parameters column: Supelco β-DEX 120, 30 m x 0.25 mm I.D., 0.25 μm (24304)
gradient: 50 °C (5 min), 5 °C/min to 200 °C (10 min)
inj. temp.: 250 °C
carrier gas: helium, 60 m/sec., constant flow
injection: 1 μL, 100:1 split
sample: 2 mg/mL in methanol
peak 1: S(+)-ibuprofen
peak 2: R(-)-ibuprofen
liner: 4 mm I.D., FocusLiner™
Featured
Industry
Clinical
Pharmaceutical (small molecule) active pharmaceutical ingredient

GC Analysis of Parabens on SLB®-5ms after SPME using 50/30 μm
DVB/Carboxen/PDMS Fiber
Paraben is an preservative

Related
Categories
Analytical/Chromatography, Antimicrobials, Applications, Capillary GC Columns and Guard
test parameters
sample/matrix: Paraben, each at 200 ppb in 3 mL water + 25% sodium chloride in a 4 mL
vial
SPME fiber: metal fiber assembly coated with 50/30 μm DVB/Carboxen/PDMS (57912-U)
extraction: immersion with stirring, 25 °C (15 min)
column: SLB-5ms, 20 m × 0.18 mm I.D., 0.36 μm (28576-U)
MSD interface: 275 °C
scan range: m/z 40-450
carrier gas: helium, 0.7 mL/min constant
liner: 0.75 mm I.D. SPME
Featured
Industry
Cosmetics, Personal Care, and Cleaning Products
Food and Beverages
Pharmaceutical (small molecule)
Properties

GC Analysis of Class 1 Residual Solvents on OVI-G43
application for GC
Related Categories
Capillary GC Columns, by method reference, Capillary GC Columns, by name,
Capillary GC Columns, by phase polarity, Chromatograms, Compound Class, GC
Applications, GC Columns for the Pharmaceutical Industry, Gas Chromatography
(GC), Intermediate Polar Capillary GC Columns, OVI-G43, Residual Solvents,
Solvents, USP
Less...
test parameters
column: OVI-G43, 30 m x 0.53 mm I.D., 3.0 μm (25396) with 5 m intermediate
polarity guard (25339) (25339)
inj. temp.: 225 °C
carrier gas: helium, 30 cm/sec @ 35 °C
injection: 1 μL, 33:1 split
liner: single taper
sample: 5 analytes, at concentrations indicated in DMSO
Featured Industry Pharmaceutical (small molecule)

GC Analysis of Camphor Enantiomers on Astec® CHIRALDEX® G-DP
application for GC
Related Categories
Active Pharmaceutical Ingredients (APIs), Analytical/Chromatography, Applications,
Astec CHIRALDEX G-DP, Capillary GC Columns and Guard Columns/Retention
Gaps, Capillary GC Columns, by industry / application, Capillary GC Columns, by
name, Chiral Capillary GC Columns, Chromatograms, Compound Class,
Enantiomers, Flavors & Fragrances, Aroma, GC Applications, GC Columns for the
Chemical Industry, GC Columns for the Flavor & Fragrance Industry, GC Columns
for the Food & Beverage Industry, GC Columns for the Pharmaceutical Industry, Gas
Chromatography (GC), Ketones, Volatiles
Less...
test parameters column: Astec CHIRALDEX G-DP, 30 m x 0.25 mm I.D., 0.12 μm (78033AST)
oven: 100 °C
inj. temp.: 250 °C
carrier gas: helium, 30 psi
sample: peaks 1 & 2: camphor enantiomers
Featured Industry
Flavors and Fragrances
Food and Beverages
Pharmaceutical (small molecule)

ADVANTAGES OF COMBINING GAS CHROMATOGRAPH AND
MASS SPECTROGRAPH
There are several advantages of putting the two devices
together in one instrument. For one, it finishes the process
faster. The accuracy of both processes is also not attained
when they are done separately. This is because the sample to
be taken into the mass spectrometer must be in its purest
state. Once the process is done separately and the sample is
taken out of the gas chromatograph, the sample will be
tampered and the results will differ. Also, when they are done
separately, there are instances that the separated elements in
the gas chromatograph have similar ionized fragment pattern
and can be misinterpreted by the mass spectrograph. At least
with putting the two devices together in one instrument, the
number of errors is reduced.

Bio fuel analysis
EN 14110: GC Analysis of Methanol Impurity in Biodiesel on Equity®-1 after SPME using 85
μm Polyacrylate Fiber
Related Categories
Alcohols, Analytical/Chromatography, Applications, Biodiesel: Methanol Impurity, Capillary GC
Columns and Guard Columns/Retention Gaps, Capillary GC Columns, by industry / application,
Capillary GC Columns, by method reference, Capillary GC Columns, by name, Capillary GC Columns, by
phase polarity, Chromatograms, Compound Class, EN, Equity-1, GC Applications, GC Columns for the
Biofuel Industry, Gas Chromatography (GC), Gases & Hydrocarbons, Non-Polar Capillary GC Columns,
SPME Applications
Less...
test parameters
sample/matrix: 2 g of B100 biodiesel containing 0.01% methanol and 0.0785% 2-propanol in a 4 mL
vial
SPME fiber: PK3 SPME ASSY 85UM POLYACRYLATE FS 24GA MAN (WHITE) (57304)
extraction: headspace, 60 °C for 5 min
desorption process: 250 °C for 0.75 min
column: Equity-1, 30 m x 0.32 mm I.D., 1.0 μm (28057-U)
oven: 50 °C
inj. temp.: 250 °C
carrier gas: helium, 30 cm/sec
liner: 0.75 mm I.D., SPME type, straight design (unpacked)
Featured Industry
Biofuels
Environmental

ENVIRONMENTAL CHECKING AND CLEANING
Have you ever wondered how environmentalists said that our air is already polluted?
How did they come up with such statement? How did they identify the elements that
pollute our air? This is where gas chromatography-mass spectrometry comes in.
Supposedly, the air we breathe should only be composed of O2. Through GC and
mass spectrometry, the other elements that mixed with O2 that make the air polluted
are separated and identified each. Through GC and mass spectrometry, the field of
environmental studies has widened.
GC Analysis of Solvents in Water on SPB®-1 SULFUR after SPME using 75 μm
Carboxen/PDMS Fiber

Related Categories
Analytical/Chromatography, Applications, Beverage Analysis (Water),
Capillary GC Columns and Guard Columns/Retention Gaps, Capillary
GC Columns, by industry / application
test parameters sample/matrix: solvents at 20 ppb in 4 mL water + 25% NaCl in 4 mL vial
SPME fiber: carboxen/PDMS, 75 μm (57318)
extraction: immersion, 10 min, rapid stirring
column: SPB-1 SULFUR, 30 m × 0.32 mm I.D., 4.0 μm film (24158)
oven: 50°C (2 min) to 150°C at 10°C/min
inj. temp.: splitless (closed 2 min), 260°C, 0.75 mm I.D. liner
detector: FID
carrier gas: helium, 30 cm/sec
Featured Industry
Environmental
Forensics and Toxicology
Properties:

CRIMINAL FORENSICS
CSI and NCIS have become the most popular criminal forensic TV
series of all times. Have you ever thought how they are able to solve
crimes even without much physical evidences? GC and MS are
responsible for this. When a person is killed with the use of chemical,
the chemical as well as the criminal can be detected through this
process. Even without the actual container of the chemical, it can still
be detected through the blood sample of the victim. In arson cases, this
is a technique used to solve the crime, specifically Pyrolysis Gas
Chromatography. This is to identify the elements that caused the fire of
the area.

DRUG IDENTIFICATION
Specific drugs are prohibited on every state. In order to detect whether
a person is taking the illegal drugs, GC and MS is applied. Drug test
makes use of these processes. Through this, the examiners can identify
what drugs have entered the body of the person through their urine,
blood, and faeces sample.
SECURITY PURPOSES
Since the September 11, 2011 incident, US airports have made their
security stricter. To execute this, all incoming and outgoing individuals
of the United States have their baggage inspected through Thermo
Detection. This process involves GCMS to detect whether the baggage
contains explosives.
ANALYSIS OF FOOD AND BEVERAGES FOR NUTRITION
PURPOSES AND PERFUME
One way to identify the nutrition value of a certain food or drink is
through GCMS. Their elements are identified individually and are then
analysed whether they should still be taken or not.

ENVIRONMENTAL MONITORING AND CLEAN UP
GC-MS is becoming the tool of choice for tracking organic pollutants
in the environment. The cost of GC-MS equipment has decreased
significantly, and the reliability has increased at the same time, which
has contributed to its increased adoption in environmental studies.
There are some compounds for which GC-MS is not sufficiently
sensitive, including certain pesticides and herbicides, but for most
organic analysis of environmental samples, including many major
classes of pesticides, it is very sensitive and effective.
CRIMINAL FORENSICS
GC-MS can analyse the particles from a human body in order to help
link a criminal to a crime. The analysis of fire debris using GC-MS is
well established, and there is even an established American Society
for Testing Materials (ASTM) standard for fire debris analysis.
GCMS/MS is especially useful here as samples often contain very
complex matrices and results, used in court, need to be highly
accurate.

GC-MS is increasingly used for detection of illegal narcotics, and may eventually
supplant drug-sniffing dogs. It is also commonly used in forensic toxicology to find
drugs and/or poisons in biological specimens of suspects, victims, or the deceased.
SECURITY
A post–September 11 development, explosive detection systems have become a
part of all US airports. These systems run on a host of technologies, many of them
based on GC-MS. There are only three manufacturers certified by the FAA to
provide these systems,[citation needed] one of which is Thermo Detection (formerly
Thermedics), which produces the EGIS, a GC-MS-based line of explosives detectors.
The other two manufacturers are Barringer Technologies, now owned by Smith's
Detection Systems, and Ion Track Instruments, part of General Electric Infrastructure
Security Systems.
FOOD, BEVERAGE AND PERFUME ANALYSIS
Foods and beverages contain numerous aromatic compounds, some naturally present
in the raw materials and some forming during processing. GC-MS is extensively
used for the analysis of these compounds which include esters, fatty acids, alcohols,
aldehydes, terpenes etc. It is also used to detect and measure contaminants from
spoilage or adulteration which may be harmful and which is often controlled by
governmental agencies, for example pesticides.

Gas chromatography–mass spectrometry (GC-MS) is a method that
combines the features of gas-liquid chromatography and mass
spectrometry to identify different substances within a test sample.
Applications of GC-MS include drug detection, fire investigation,
environmental analysis, explosives investigation, and identification of
unknown samples. GC-MS can also be used in airport security to
detect substances in luggage or on human beings. Additionally, it can
identify trace elements in materials that were previously thought to
have disintegrated beyond identification.
GC-MS has been widely heralded as a "gold standard" for forensic
substance identification because it is used to perform a specific test. A
specific test positively identifies the actual presence of a particular
substance in a given sample. A non-specific test merely indicates that
a substance falls into a category of substances. Although a non-
specific test could statistically suggest the identity of the substance,
this could lead to false positive identification.

From war zones or scenes of natural disasters, news reporters often comment on the stench of
decaying bodies. This characteristic malodour is made up of a complex mixture of volatile
compounds that might be useful in forensic pathology, to establish the cause of death and the
post-mortem interval. In the normal world, this characteristic smell is also well known to
members of the police force, crime scene technicians, medical staff and forensic pathologists,
as well as to some dogs. Its composition is the trigger used by tracker dogs to locate hidden
bodies. The same odour is also recognised by insects that quickly colonise a body once it
begins to decay. Now, Greek researchers have suggested that the odour can be used to
determine the time since death and possibly help to establish the cause of death. First of all,
they remind us that the VOCs that constitute the smell arise from the same sources in each
human corpse. Carbohydrates in the body break down to give mainly oxygenated compounds
(alcohols, aldehydes, ketones, acids, esters, ethers), proteins degrade to nitrogen, phosphorus
and sulphur compounds, nucleic acids from nitrogen and phosphorus compounds and lipids
decompose to nitrogen, phosphorus and oxygenated compounds and hydrocarbons. So, in
theory, different decaying bodies should produce the same set of VOCs (volatile organic
compounds) he adsorbed gases were analysed by thermal desorption GC/MS and the
components were identified from their retention times and mass spectra using a commercial
database and an in-house database constructed from standard compounds. The results were
described in Forensic Sci. Intl. 2005. A total of 86 substances were identified and quantified
with the aid of internal standard compounds. he relatively high levels of toluene were
unexpected, leading the authors to hint at the possibility of toluene poisoning of the victims.
The high number of fatty acid esters found was explained in terms of saponification. Many
hydrocarbons, aldehydes, ketones and alcohols were also detected.
GC AND THE SMELL OF DEATH(CORPSES)

Sniffer dogs can track the scent of human bodies

APPLICATIONS OF GAS CHROMATOGRAPHY (GC

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