GC columns
Phases
ACR phase Phase description USP
reference nomenclature
100% Dimethyl Polysiloxane G1, G2, G38
• Classic dimethyl polysiloxane technology with high temperature cross-linking
• Excellent general purpose GC column
ACR-1 • Low bleed
• Non-polar
• Suitable for all routine analyses
Application areas: Suitable for analysis of hydrocarbons, aromatics, pesticides, phenol, herbicides, amines
5% Phenyl / 95% Dimethyl Polysiloxane G27, G36
• Excellent general purpose GC column
• Low bleed
ACR-5
• Non-polar
• High temperature
Application areas: Aromatics, pesticides, herbicides, drugs of abuse, hydrocarbons
5% Phenyl Polysilphenylene-siloxane G27, G36
• Perfect for your 5% GCMS analysis
ACR-5MS
• Optimized silphenylene content for general purpose MS analyses
Application areas: 5% GCMS analyses
5% Phenyl Polysilphenylene-siloxane
• High temperature
• General purpose GC column - suitable for over 80% of all routine analyses performed by gas chromatography
• Very low bleed - ideal for trace analysis
ACR-X5 • Non-polar
• Extremely inert
• Ideal for GCMS
Application areas: Ultra trace analyses, pesticides/herbicides, hydrocarbons, solvents, phenols, amines,
GCMS and other specific detector applications
5% Phenyl (equiv.) Polycarborane siloxane
• Ultra high temperature column range
• Unique phase – no equivalent phases
ACR-HT5
• Ideal for simulated distillation applications (petroleum industry)
Application areas: Simulated distillation, general hydrocarbon profiles, pesticides/herbicides, GCMS
applications
Polyethylene Glycol (PEG) – TPA Treated
• Nitroterephthalic acid modified PEG
ACR-FFAP • Polar phase
• Ideal for low molecular weight acids
Application areas: Volatile free acids, fatty acid methyl esters, alcohols, aldehydes, acrylates, ketones
35% Phenyl Polysilphenylene-siloxane G42
• Mid polarity column
• Ideal for conformational analysis
• Inert
ACR-X35
• High temperature
• Low bleed
Application areas: Environmental analyses, pesticides/herbicides, drugs of abuse, pharmaceuticals,
polynuclear aromatic hydrocarbons, GCMS applications
50% Phenyl Polysilphenylene-siloxane G3
• Mid polarity
• Inert
• Low bleed
ACR-X50
• High temperature
• Ideal for a range of EPA methods and pharmaceutical applications
Application areas: EPA methods 604, 608, 8060, 8081, triazines/herbicides, drug screening, steroids and a
variety of pharmaceutical applications
Cyanopropylphenyl Polysiloxane G43
• US EPA method 624 optimized column
ACR-624 • Designed for volatiles analysis
• Ideal for EPA methods 624, 8240 and 8260 and method SW-846
Application areas: EPA method 624, drinking water volatiles, chlorinated hydrocarbons solvents
14% Cyanopropylphenyl Polysiloxane G46
• Ideal for organochlorine pesticides analysis
• Highly inert
ACR-10
• Low bleed
Application areas: Environmental analyses (EPA methods 608 and 8081), pesticides/herbicides, drugs of
abuse, pharmaceuticals
70% Cyanopropyl Polysilphenylene-siloxane G8, G48
• High temperature
• Custom designed for separation of fatty acid methyl esters (FAMEs)
ACR-X70 • Industry standard column for FAME analysis
• Ideal for cis/trans isomer separation
• Polar phase
Application areas: Fatty acid methyl esters, carbohydrates, pharmaceuticals, GCMS applications
90% Cyanopropyl Polysilphenylene-siloxane
• Unique bonded phase
• Highly polar
ACR-X90
• Thermally stable
Application areas: Fast separation of fragrances, aromatics, petrochemical, pesticides, PCBs and isomers of
Fatty Acid Methyl Esters (FAMEs)
Polyethylene Glycol G14, G15,
• Industry standard wax column G16, G20, G39
ACR-WAX • Polar phase
• Cross-linked for stability and washing
Application areas: Alcohol, free acids, fatty acid methyl esters, aromatics, solvents, essential oils
Trajan is pleased to be able to offer
a range of GC columns that provide
consistent and repeatable
separations for your analytical
analysis
Trajan GC columns
The GC column carries out the separation. When selecting a column for an application, four
basic parameters need to be considered:
• Stationary phase
• Column internal diameter
• Film thickness
• Column length
A GC column is generally specified with two maximum operating temperatures:
• T
he isothermal limit at which the column may be run continuously.
• A programmed maximum where the column reaches a maximum for a limited period only.
There is also a minimum temperature below which a column will perform poorly. If a column
is run continuously at the upper limit of temperature, column bleed will be observed. This is
background noise caused by stationary phase degradation and this increases with increased film
thickness.
Adjusting GC column performance
Parameters affecting resolution
Column parameter Performance changes
Efficiency Retention Selectivity
Column length (m) Doubling column length increases resolution by ~40%
The smaller the column ID, the greater the efficiency and better the
Internal diameter (mm) resolution
The thicker the film, the greater the retention e.g. ideal for highly
Film thickness (µm) volatile compounds. The thinner the film, the sharper the peaks
and lower the bleed
Altering the stationary phase can affect elution order and help
Stationary phase chemistry separate closely, or co-eluting peaks
GC columns for your analytical analysis
Stationary phase
General rules on selecting a phase
• Select the least polar phase that will perform the separation you require.
• Non-polar stationary phases separate analytes predominantly by order of boiling point.
Increase the amount of phenyl and/or cyanopropyl content in the phase, and the separation is
then influenced more by differences in dipole moments or charge distributions (please refer to
list of phase descriptions).
• To separate compounds that differ more in their hydrogen bonding capacities (for example
aldehydes and alcohols), polyethylene glycol type phases are best suited (please refer to list of
phase descriptions).
• Wherever possible use published retention indices to assist in your selection. Retention
indices are calculated for a range of probe compounds which can highlight specific selectivity
characteristics of a stationary phase.
Retention indices for seven cross-linked phases
The use of retention indices is a valuable tool in assisting selection of the stationary phase which
provides maximum resolution for the compounds to be analyzed.
The retention indices of the five test compounds indicate the differences and similarities of each
stationary phase. The values are calculated in reference to a homologous series of n-alkane
hydrocarbons plotted on a logarithmic scale. Each n-alkane has a retention index of 100
times the carbon number (ie. C6, RI=600). Therefore, the retention index for each of the test
compounds illustrates the elution position in reference to this n-alkane series.
Each probe compound is selected to represent the interaction characteristics
of various organic functionalities.
Probe compound Interactions represented
Retention indices are calculated using
Benzene Aromatics, unsaturated hydrocarbons
the following formula: Butanol Alcohols, diols
2-Pentanone Ethers, esters, ketones and aldehydes
IA = 100N+100n (log t'R(A) - log t'R(N) ) / Nitropropane Nitro and nitrile derivatives
(log t'R(N+n) - log t'R(N) ) Pyridine Aromatic bases
IA is the retention index of compound A (from corrected retention times) which elutes between two n-paraffins separated by
either one or two carbon numbers.
Phase Benzene (X) Butanol (Y) 2-Pentanone (Z) Nitropropane (U) Pyridine (S) Average
ACR-1 647 646 666 707 722 678
ACR-5 667 665 692 743 746 703
ACR-X5 664 667 697 752 750 706
ACR-35 728 726 763 862 848 785
ACR-10 709 774 772 862 832 790
ACR-WAX 947 1153 998 1217 1185 1100
ACR-X70 1067 1219 1170 1365 1300 1224
The tables lists the responses to each test compound and the average value for seven cross-linked phases ranging from the
non-polar ACR-1, ACR-5, ACR-X5, ACR-X35, ACR-10, ACR-WAX, ACR-X70. The range has been developed to cover the
widest possible range of compound functionality and application areas.
Average retention index values are listed, and provide an indication of the phase polarity. This can assist in selecting a
suitable stationary phase for a particular application area. The individual responses to each test compound can further assist
in determining the best phase for any specific type or group of compounds.
Column internal diameter
Effect of column internal diameter
Effect of column internal diameter
The smaller the internal diameter the greater the R=4.00
efficiency and therefore the better the resolution.
Reduce the diameter by half and the column efficiency
doubles.
0.1 mm ID
As the diameter increases, the film thickness can
increase to maintain the same phase ratio. The thicker R=1.63
the film, the greater the loading capacity. Overloading
a column will always result in loss of resolution. If the
column diameter is halved while maintaining the same
film thickness, then the loading capacity will also be 0.25 mm ID
halved. 0 minutes 10
Column ID Recommendations
0.1 mm and 0.15 mm Fast GC columns ideal for FID, ECD.
0.22 mm and 0.25 mm Ideal for MS and high resolution applications.
0.32 mm Provide good resolution for most applications, ample sample loading and compatibility with nearly all detector systems.
0.53 mm Provide large sample capacities.
Film thickness
Film thickness and elution temperature
Sample loading
ACR-1, 0.25 μm ACR-1, 1.0 μm ACR-1, 5.0 μm For samples with a variation in solute concentration, a
ß=320 ß=80 ß=16 thick film column is recommended. This will reduce the
40°C 75°C 120°C possibility of broad overloaded peaks co-eluting with
2 2 2 other compounds of interest. If the separation of two
solutes is sufficient and co-elution is still unlikely, even
1 1 1
with large differences in concentration, then a thinner
3 3 3 film can be used.
Volatility of solute
The greater the film thickness, the greater the
retention of a solute, therefore the higher the elution
k=4.95 k=4.85 k=5.50 temperature. As a rule, doubling the film thickness
results in an increase in elution temperature of
approximately 15-20°C, under isothermal conditions.
Using a temperature program, the increase in elution temperature is slightly less.
As well as film thickness, changing the column internal diameter also effects the elution
temperature. To avoid using two parameters that can alter individually, phase ratio is often used
as it takes both into account.
The chromatograms demonstrate the effect on elution temperature for a mixture of compounds
using 0.32 mm ID columns with film thickness of 0.25 μm, 1 μm and 5 μm.
An increase in film thickness from 0.25 μm to 5 μm needs a change in analysis temperature of
80°C to maintain the same elution time.
GC columns for your analytical analysis
Film thickness continued
Phase ratio
Phase ratio encompasses both the film thickness and column internal diameter to give a value
that can characterize all column internal diameters and film thickness combinations.
Calculate phase ratio using the following formula:
ß = d/4df
where:
ß = phase ratio
d = column internal diameter (μm)
df = film thickness (μm)
From the phase ratio value, a column can be categorized for the type of application it would best
suit. The smaller the ß value, the greater the concentration of phase to the volume of the column,
making it better suited for analyzing volatile compounds. Columns which have thin films, are
generally better suited for high molecular weight compounds and are characterized by large ß
values.
Column ID (μm)
Film thickness (µm) 100 150 220 250 320 530
Phase ratio
0.1 250 - 550 625 800 1325
0.15 - - - - - 883
0.25 - 150 220 250 320 530
0.5 - 75 110 125 160 265
1.0 - - 55 63 80 132
3.0 - - - - 27 44
5.0 - - - - 16 26
Keeping a similar phase ratio when changing column internal diameters will ensure that your
chromatographic parameters will not need substantial changes.
Column length
Effect of column length Effect of column length Components
1. o-Ethylphenol
Phase: ACR-WAX, 0.5 μm
Always try to select the shortest column length that will Temperature: 170°C, isothermal
2. p-Cresol
3. 2,4-Xylenol
provide the required resolution for the application (12-30 m). Linear velocity: 25 cm/sec, He
4. 2,5-Xylenol
5. 2-iso-Propylphenol
3 3
If the maximum column length available is being used and 3
resolution of the sample mixture is still inadequate, try 2
changing the stationary phase or internal diameter. 5
2
5
2
5
1 1 1
Resolution is proportional to the square root of the
4 4 4
column efficiency. Therefore, doubling the column length
will only increase the resolving power of the column by 12 m x 25 m x 50 m x
0.32 mm ID 0.32 mm ID 0.32 mm ID
approximately 40%. Efficiency Efficiency Efficiency
(effective (effective (effective
The three chromatograms give an indication of how column plates): 25,000 plates): 50,000 plates): 100,000
length influences the resolution of a mixture.
Part numbers
Phase Description 056668 30 m x 0.32 mm ID - ACRHT5 0.5 µm
ACR-1 056672 30 m x 0.53 mm ID - ACRHT5 0.5 µm
056039 15 m x 0.25 mm ID - ACR1 0.1 µm ACR-10
056043 15 m x 0.25 mm ID - ACR1 0.25 µm 056256 30 m x 0.25 mm ID - ACR10 0.25 µm
056044 30 m x 0.25 mm ID - ACR1 0.25 µm 056259 30 m x 0.32 mm ID - ACR10 0.25 µm
056045 60 m x 0.25 mm ID - ACR1 0.25 µm 056270 30 m x 0.32 mm ID - ACR10 1.0 µm
056056 30 m x 0.25 mm ID - ACR1 1.0 µm 056283 30 m x 0.53 mm ID - ACR10 1.0 µm
056062 30 m x 0.32 mm ID - ACR1 0.25 µm ACR-WAX
056068 30 m x 0.32 mm ID - ACR1 0.5 µm 056415 30 m x 0.25 mm ID - ACR20 0.5 µm
056069 60 m x 0.32 mm ID - ACR1 0.5 µm 056427 30 m x 0.25 mm ID - ACR20 0.25 µm
056073 30 m x 0.32 mm ID - ACR1 3.0 µm 056428 60 m x 0.25 mm ID - ACR20 0.25 µm
056085 60 m x 0.32 mm ID - ACR1 5.0 µm 056433 30 m x 0.32 mm ID - ACR20 0.25 µm
056090 30 m x 0.53 mm ID - ACR1 1.0 µm 056434 60 m x 0.32 mm ID - ACR20 0.25 µm
056806 30 m x 0.53 mm ID - ACR1 5.0 µm 056438 30 m x 0.32 mm ID - ACR20 0.5 µm
056807 60 m x 0.53 mm ID - ACR1 5.0 µm 056439 30 m x 0.25 mm ID - ACR20 1.0 µm
056808 30 m x 0.53 mm ID - ACR1 3.0 µm 056440 30 m x 0.53 mm ID - ACR20 0.5 µm
056809 60 m x 0.53 mm ID - ACR1 3.0 µm 056444 30 m x 0.32 mm ID - ACR20 1.0 µm
056810 60 m x 0.32 mm ID - ACR1 1.0 µm 056445 60 m x 0.32 mm ID - ACR20 1.0 µm
056812 60 m x 0.25 mm ID - ACR1 0.5 µm 056450 15 m x 0.53 mm ID - ACR20 1.0 µm
056813 30 m x 0.32 mm ID - ACR1 1.0 µm 056451 30 m x 0.53 mm ID - ACR20 1.0 µm
056815 60 m x 0.25 mm ID - ACR1 1 µm 0564515 60 m x 0.53 mm ID - ACR20 1.0 µm
056820 30 m x 0.25 mm ID - ACR1 0.5 µm 056457 60 m x 0.32 mm ID - ACR20 0.5 µm
ACR-X5 056458 60 m x 0.25 mm ID - ACR20 0.5 µm
056100 15 m x 0.25 mm ID - ACRX5 0.25 µm ACR-FFAP
0561010 30 m x 0.25 mm ID - ACRX5 0.25 µm 056465 30 m x 0.25 mm ID - ACRFFAP 0.25 µm
0561011 30 m x 0.25 mm ID - ACRX5 0.1 µm 056466 60 m x 0.25 mm ID - ACRFFAP 0.25 µm
056102 60 m x 0.25 mm ID - ACRX5 0.25 µm 056471 30 m x 0.32 mm ID - ACRFFAP 0.25 µm
0561025 30 m x 0.25 mm ID - ACRX5 0.5 µm 056472 60 m x 0.32 mm ID - ACRFFAP 0.25 µm
0561205 30 m x 0.32 mm ID - ACRX5 0.5 µm 056477 30 m x 0.53 mm ID - ACRFFAP 0.5 µm
056121 15 m x 0.25 mm ID - ACRX5 1.0 µm 056478 30 m x 0.53 mm ID - ACRFFAP 1.0 µm
0561220 30 m x 0.25 mm ID - ACRX5 1.0 µm ACR-X35
056123 60 m x 0.25 mm ID - ACRX5 1.0 µm 056701 30 m x 0.25 mm ID - ACRX35 0.25 µm
0561345 30 m x 0.53 mm ID - ACRX5 0.5 µm 056702 60 m x 0.25 mm ID - ACRX35 0.25 µm
0561348 30 m x 0.53 mm ID - ACRX5 1.5 µm 0567158 30 m x 0.32 mm ID - ACRX35 0.5 µm
056144 15 m x 0.32 mm ID - ACRX5 0.25 µm 056724 30 m x 0.32 mm ID - ACRX35 0.25 µm
056145 30 m x 0.32 mm ID - ACRX5 0.25 µm 056737 30 m x 0.53 mm ID - ACRX35 1.0 µm
0561460 60 m x 0.32 mm ID - ACRX5 0.25 µm ACR-X50
056148 30 m x 0.53 mm ID - ACRX5 1.0 µm 056749 30 m x 0.25 mm ID - ACRX50 0.1 µm
056153 30 m x 0.32 mm ID - ACRX5 1.0 µm 056750 15 m x 0.25 mm ID - ACRX50 0.25 µm
056154 60 m x 0.32 mm ID - ACRX5 1.0 µm 056751 30 m x 0.25 mm ID - ACRX50 0.25 µm
056160 30 m x 0.53 mm ID - ACRX5 3.0 µm 056752 60 m x 0.25 mm ID - ACRX50 0.25 µm
0562170 15 m x 0.25 mm ID - ACRX5 0.1 µm 056761 30 m x 0.32 mm ID - ACRX50 0.25 µm
ACR-5 056772 30 m x 0.53 mm ID - ACRX50 1.0 µm
056177 30 m x 0.32 mm ID - ACR5 0.25 µm ACR-X70
0561820 15 m x 0.25 mm ID - ACR5 0.25 µm 056616 30 m x 0.32 mm ID - ACRX70 0.25 µm
056183 30 m x 0.25 mm ID - ACR5 0.25 µm 056617 60 m x 0.32 mm ID - ACRX70 0.25 µm
056184 60 m x 0.25 mm ID - ACR5 0.25 µm 056620 30 m x 0.53 mm ID - ACRX70 0.5 µm
0561880 60 m x 0.32 mm ID - ACR5 1.0 µm 056622 30 m x 0.25 mm ID - ACRX70 0.25 µm
056189 30 m x 0.32 mm ID - ACR5 1.0 µm 056623 60 m x 0.25 mm ID - ACRX70 0.25 µm
056195 30 m x 0.53 mm ID - ACR5 1.0 µm ACR-X90
0561960 30 m x 0.53 mm ID - ACR5 5.0 µm 056570 15 m x 0.25 mm ID - ACRX90 0.25 µm
056199 15 m x 0.53 mm ID - ACR5 1.5 µm 056580 30 m x 0.25 mm ID - ACRX90 0.25 µm
056203 30 m x 0.25 mm ID - ACR5 1.0 µm 056583 30 m x 0.32 mm ID - ACRX90 0.5 µm
056216 30 m x 0.32 mm ID - ACR5 0.5 µm 056590 60 m x 0.25 mm ID - ACRX90 0.25 µm
ACR-5MS ACR-624
056308 15 m x 0.25 mm ID - ACR5MS 0.25 µm 056980 30 m x 0.25 mm ID ACR-624/vol 1.4 µm
056310 30 m x 0.25 mm ID - ACR5MS 0.25 µm 056981 60 m x 0.25 mm ID ACR-624/vol 1.4 µm
056320 30 m x 0.32 mm ID - ACR5MS 0.25 µm 056982 30 m x 0.32 mm ID ACR-624/vol 1.8 µm
ACR-HT5 056983 60 m x 0.32 mm ID ACR-624/vol 1.8 µm
056633 15 m x 0.25 mm ID - ACRHT5 0.1 µm 056984 30 m x 0.53 mm ID ACR-624/vol 3.0 µm
056634 30 m x 0.25 mm ID - ACRHT5 0.1 µm 056985 60 m x 0.53 mm ID ACR-624/vol 3.0 µm
056667 15 m x 0.32 mm ID - ACRHT5 0.5 µm
Trajan GC columns
Trajan is pleased to be able to offer a range of GC columns
that provide consistent and repeatable separations for your
analytical analysis.
For technical information contact
techsupport@trajanscimed.com
Trajan Scientific and Medical
BR-0587-G © Trajan Scientific Australia Pty Ltd 10/2020
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