Buck Scientific, Inc.
Seminar in ANALYTICAL
INSTRUMENTATION for
Spectroscopy & Chromatography:
GAS CHROMATGRAPHY
GAS CHROMATOGRAPHY (GC)
Theory & Principle of OPERATION
Using a pressurized “Carrier” Gas to push a
Sample through a narrow Column filled or
lined with a Polar “Packing” and
Temperature Program; the VOLATILE
Species present in that Sample can be
properly separated for Identification and
Quantitation on selected Detectors
Basic GC Theory
ALL Organic
Molecules will have
a characteristic
Retention Time on a
specific Column at a
specific Temperature
which can provide
both Qualitative and
Quantitative data
Basic GC Design
The ORIGINAL Gas Chromatograph from
Perkin-Elmer in 1962 was 2 meters long and
weighed ~100 kilos! They required large
amounts of Gas and used up a big cylinder of
Helium in only 3 days!! Hewlett-Packard
introduced their GC system in 1965 (#5700),
and still has the SAME basic hardware 35 years
later; just in a “prettier” package (#6890)!
Basic CHROMATOGRAPH Design
ALL Analytical Chromatographs have several
BASIC design components in common:
INJECTION PORT
COLUMN
OVEN
DETECTOR
OUTPUT
Buck GC Design
BUCK Scientific developed the 600-series,
small-sized GC back in 1988; using the
SAME technology as Hewlett-Packard did
in their large, heavy, high-$ system; but at
1/4 the size and 1/3 the price with NO loss
of Analytical Data Quality. BUCK uses the
SAME high-quality Columns to get the
SAME high-quality Data.
Buck GC Design
The new BUCK 910-series
GC Instruments use a very
efficient, compact Oven
with Electonic Pressure
Control [EPC] for very
specific requirements to
insure very reproducible
separations.
“Open-Architecture” design allows BUCK to custommake ANY GC system rapidly and reliably.
BUCK GC Hardware
The advantages of the compact size, more
efficient Oven design and precise Temperature
control developed into a popular product line for
all areas of Analysis = University, Pollution,
Petrochemical, Polymer Science, Cosmetics,
Food Technology; since we can assemble any
required Hardware Configuration to meet the
customer’s EXACT Analytical needs!
SYSTEM Design
The State-of-the-Art 910-series Gas Chromatographs
from BUCK Scientific provide COMPLETE
Flexibility and Capability for ANY GC analyses, with
as many as 3 Injectors & up to 4 Detectors per unit!
Any configuration can
be designed to meet
YOUR requirements
for your Lab’s needs!
Injectors
• Injector - (Liquid or Gas Sample)
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Direct on-column
Gas Sampling Valve
Purge & Trap
SPME Fibers
Headspace
Split/Splitless
Thermal Desorption
Autosamplers
COLUMN Technology
Advances in the
design & construction
of COLUMNS has
opened up many new
Applications that
were not possible a
few years ago…..
Basic GC Columns
• There are TWO Primary Modes of doing
GC Analyses:
– 1/8”Glass or Stainless Steel PACKED
Column for Medium Resolution and
large Sample Volumes
– Fused Silica or Metal Capillary Colum
for High Resolution and smaller Sample
Volumes
Basic GC Columns
Developments in the fabrication of Metal Tubing
has allowed Megabore (0.53mm) and Capillary
(0.32mm) Columns to be designed in high-grade
Stainless Steel (non-corrosive & unbreakable)
instead of the more fragile & expensive Fused
Silica.
Research has also shown the METAL Columns
have ~15% BETTER resolution than Silica!
GC OVEN Features
SMALL size Oven = LESS wasted Time & Energy
• Heating Range (Ambient - 450°C)
– Good for Petroleum “SIMDIS” work
• FASTEST Heating Rate (= Faster analysis)
• Column Fittings
– 1/4” & 1/8” Packed
– .53mm Megabore Capillary
– Microbore Capillary
GC Detectors
• Thermal Conductivity Detector (TCD)
– General Purpose, responds to all molecules
– Detection levels of 100ppm - 100%
– Useful for Permanent Gases
• Catalytic Combustion Detector (CCD)
– Very general use, does not require support gas
• Helium Ionization Detector (HID)
– More sensitive TCD type detector (10-25ppm)
GC Detectors
• Flame Ionization Detector (FID)
– General Purpose, specific to hydrocarbons
– Detection levels of 5ppm - 10%
– Useful for General Organic Analysis
• Photo Ionization Detector (PID)
– Specific for Aromatic & Olefinic Compounds
– Very sensitive (0.1ppm)
– Useful for BTEX and Environmental Samples
GC Detectors
• Flame Photometric Detector (FPD)
– Sulfur or Phosphorus bearing compounds
– Detection levels of <0.1ppm
– Useful in combustion streams and pesticides
• Nitrogen Phosphorus Detector (NPD)
– Specific to Nitrogen & Phosphorus bearing
compounds (100ppb detection)
– Useful for Pesticides, Herbicides & Drugs
GC Detectors
• Dry-Electrolytic Conductivity (DELCD)
– Good linear response to Halogen atoms created
in FID flame. Detection levels of 1-10ppb
– Useful for Chlorinated HCs and Environmental
• Electron Capture Detector (ECD)
– *** NO LONGER AVAILABLE!!!!
– Cost for Radio-Active License is Too HIGH!
GC Chromatographic Controls
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Higher Temperature = Closer Peaks
Faster Heating = Faster Separation
Higher Gas Flow = Closer Peaks
Less Temp., Heating, Flow = Better Resolution
Controlled Flow = Closer Peaks with minimum
loss of resolution
BALANCE Run-time & Separation!
910 GC - Product
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Laboratory grade GC systems
Most economical pricing structure
Compact, Rugged, Reliable
Open architecture design for flexibility
Model 310 half-size chassis for portability
Various pre-configured systems
910 GC - Features
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PeakSimple Software
Unlimited Temperature Programming
Fast Cool from 400°C to 50°C in <5 min.
Electronic Pressure Controls (EPC)
Several Injector, Detector, and other options
Single and dual-oven options
910-GC Features
• Ideal for QA/QC for Manufacturing
• Excellent for Environmental & Basic
Research
• Wide Variety of Sampling Techniques
– SPME / Rapid, simple & accepted!
– Continuous Flow Purge&Trap for VOCs
– Programmable Headspace Analysis
PeakSimple Software Features
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Instant Peak Identification
Multi-level Calibration Curves
Auto Calibration
Manually Re-integrate Chromatograms
Click and Drag Retention Windows
Overlay Chromatograms
Control of internal/external devices
GC APPLICATIONS
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Environmental Monitoring
Pharmaceuticals & Drugs
Petrochemicals & Solvents
Cosmetic Manufacturing
Paints & Finishes
Food Technology
Education & University Research
APPLICATIONS
Since ALL Chromatographic
Techniques are RELATIVE (not
ABSOLUTE like Spectroscopy), GC is
strictly for QUANTITATIVE
determination of Known, Volatile
Compounds only…. Since non-volatile
materials will destroy the column.
APPNOTE - Environmental
SAMPLE: Insecticide Sprays for Bugs
PREPARATION: ~100mg. of Spray Sample is
placed in a Vial and diluted to 1ml. w/ Hexane
ANALYSIS: 910-GC w/ Heated Injector,
FID (for general Solvent) and
DELCD (halogenated)
RESULT: Use Reference
Standards to ID & measure
the components in the Spray
APPNOTE - Environmental
TWO Detectors
confirm the ID of
the primary
PESTICIDE
Compounds w/
Integrated Area
for Concentration
APPNOTE - Industrial
SAMPLE: Paints & Lacquers for VOCs
PREPARATION: None, weigh ~500mg. of
Paint Sample into 40ml. VOC / Headspace Vial
ANALYSIS: 910-GC w/ Headspace Sampler
and FID Detector
RESULT: Use Reference
Standards to ID & measure
the components in the Spray
APPNOTE - Industrial
Clean peaks
due to high
resolution of
the Capillary
Column give
accurate data
for the VOCs
in this Sample
APPNOTE - Food & Nutrition
SAMPLE: Food & Vegetable Oils
PREPARATION: Weigh ~500mg. of Oil into a
Vial and convert to Fatty Acid Methyl Esters to
determine the Saturation value for the Oil
ANALYSIS: 910-GC, FID,
Heated On-Column Injector
RESULT: Use Reference
Fatty Acid Standards to ID &
measure those in the Oil
APPNOTE - Food & Nutrition
This is a Standard
Method for Oil
Analysis & the
Data is used to
Characterize the
Oil Quality and
Health properties