ACE Comparison Guide - Analítica · 2 This Guide provides the following comparison data on...

■ Stationary Phase Specifications

■ Phases Compared According to Relative Hydrophobicity

■ Comparison of Column Efficiency for a Neutral Compound

■ Phases Compared According to Metal Activity

■ Phases Grouped According to Silanol Activity

■ Comparison of Column Efficiency for Basic Compounds

■ Categorization of Phases According to Silanol Activity and Inertness

Comparison Data on Commonly Used C18 Phases

ComparisonGuide

T O C18 RE V E R S E D PH A S EHPLC CO L U M N S

ComparisonGuide

2

This Guide provides the following comparison data on commonly used C18 phases:

Stationary Phase Specifications (p.3)Specifications provided by column manufacturers

Phases Compared According to RelativeHydrophobicity (p.4-5)Retention data for hydrophobic and neutral compounds

Comparison of Column Efficiency for a Neutral Compound (p.6)

Phases Compared According to Metal Activity (p.7)

Phases Grouped According to Silanol Activity (p.7)

Comparison of Column Efficiency forBasic Compounds (p.8-11)Also measures peak tailing

Categorization of Phases According toSilanol Activity and Inertness (p.12)

Stationary Phase SpecificationsStationary phase specifications providebasic information that can be helpful indeciding which phases to select for evaluation. For example, phases with high surface area and high carbon loadwill generally retain hydrophobic com-pounds longer than phases with low surface area and low carbon load. If youare analyzing macromolecules, such aspeptides and proteins, a wider pore (200 — 300 Å) phase usually providesbetter performance than a phase withsmall pores. New high purity silicas usually provide better peak shape forbasic compounds than older, more acidicsilicas (see Figure 2). Stationary phasespecifications, however, will not give youenough information to accurately predictretention or band spacing (selectivity).This is especially true when separatingpolar compounds.

IntroductionThere are so many different C18 columnsto choose from, that finding the right column for a particular separation can be very time consuming and expensive.Two apparently similar C18 phases cangive very different results. For example,Figure 1 compares the separation of the same sample mixture on a HypersilHyPURITY C18 and a Symmetry C18 column under identical mobile phase conditions. Even though both columnsare packed with “new generation” C18stationary phases, the band spacing(selectivity) between peaks is very different on the two columns. Without

more information, it is impossible to predict how the performance of differentstationary phases will compare.

This Comparison Guide to C18 ReversedPhase HPLC Columns provides basiccomparison information on commonlyused C18 columns to help you more easily identify similarities and differencesbefore investing time and money in chromatographic testing. Hopefully, thisinformation will help you find the rightcolumn for your application quicker.

Only silica based C18 bonded phases areevaluated in this Guide. Other bondedphases, such as C8, CN, Phenyl and polarembedded phases, are excluded.

This Guide does not identify an overall“best” column.The column that worksbest for one application will not necessar-ily be the column that will work best forother applications.And, there certainly isnot a single column that will work bestfor all applications. However, this Guidecan help you identify columns that arelikely to perform well so that at least youcan narrow the number of columns forchromatographic testing.You may findthat this Guide helps you identify severalcolumns that provide good separationsand performance. It is always desirable tohave more than one column identified foran application, especially if you are run-ning routine assays.

Increasingly, chromatographers are seek-ing to identify alternate brands of HPLCcolumns suitable for their assays. Havingan alternate column choice for a methodreduces the risk of “down time” due tocolumn problems such as a change inselectivity from one manufactured lot toanother or slow supplier delivery. Findingan alternate or back-up column that willprovide acceptable selectivity and performance when substituted into amethod can be as expensive and time consuming as finding the right columnfor developing an initial separation. It isour hope that this Guide will make thatjob easier by identifying columns withsimilar chromatographic characteristics.

0 1 2 3 4 5 6 7 8 9 10 11Time (min)

12

3 45

6

7

0 1 2 3 4 5 6 7 8 9 10 11Time (min)

1

2

3 4

5

6

7

Figure 1

Apparently Similar C18 Phases Can GiveVery Different Chromatographic Results

Mobile Phase: 60% CH3CN40% 50mM KH2PO4, pH 3.2

Sample: 1. Uracil 5. N,N-Dimethylaniline2. Pyridine 6. 4-Butylbenzoic acid3. Phenol 7. Toluene4. Dimethyl phthalate

Both Symmetry C18 and Hypersil HyPURITY C18 are new generation phases. You would expect them to provide similar performance, and in some casesthey do. However, in the example given here you cansee significant differences in peak retention times,selectivity, and even peak shape.

Column: Symmetry C18

Column: Hypersil HyPURITY C18

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Particle Pore Surface Carbon High PurityStationary Phase Size (µm) Size (Å) Area (m2/g) Load (%) Endcapped Silica

ACE C18 5 100 300 15.5 yes yesACE C18-300 5 300 100 9.0 yes yesACE C18-HL 5 90 400 20.0 yes yesµBondapak C18 10 125 330 10 yes noCapcell Pak AG C18 5 120 300 15 yes noCapcell Pak UG C18 5 120 300 15 yes yesCosmosil C18-AR 5 120 300 17 yes yesDevelosil ODS-HG 5 140 300 18 yes yesDevelosil ODS-MG 5 100 450 15 yes yesDevelosil ODS-UG 5 140 300 18 yes yesExsil ODS 5 100 200 11 yes noExsil ODS1 5 100 200 11 yes noExsil ODSB 5 100 200 12 yes noGemini C18 5 110 375 14 yes -Genesis C18 4 120 300 - yes yesHichrom RPB 5 110 340 14 yes yesHypersil BDS C18 5 130 170 11 yes noHypersil GOLD 5 180 200 10 yes yesHypersil HyPURITY C18 5 180 200 13 yes yesHypersil ODS 5 120 170 10 yes noInertsil ODS 5 100 350 14 yes noInertsil ODS3 5 100 450 15 yes yesInertsil ODS2 5 150 320 18.5 yes yesKromasil C18 5 100 340 19 yes yesLiChrosorb RP-18 10 100 300 17 no noLiChrospher RP-18 5 100 350 21.6 no noLuna C18(2) 5 100 400 17.5 yes yesNovapak C18 4 60 120 7.3 yes noNucleosil C18 5 100 350 15 yes noNucleosil C18 HD 5 100 - 20 yes yesNucleosil C18AB 5 100 350 24 yes noPartisil ODS 10 85 350 5 no noPartisil ODS2 10 85 350 15 yes noPartisil ODS3 10 85 350 10.5 yes noProdigy ODS2 5 150 310 18.4 yes yesProdigy ODS3 5 100 450 15.5 yes yesPurospher RP18-e 5 80 500 - yes yesResolve C18 5 90 200 10 no noSunFire C18 5 100 340 16 yes yesSymmetry C18 5 100 335 19 yes yesTSK ODS-120T 5 120 - 22 yes noTSK ODS-80TM 5 80 - 15 yes noUltrasphere ODS 5 80 - 12 yes noVydac 218MS 5 300 70 - yes noVydac 218TP 5 300 70 8 yes noVydac Selectapore 300M 5 300 70 - yes yesVydac Selectapore 300P 5 300 70 - yes yesVydac Selectapore 90M 5 90 250 - yes yesWaters Spherisorb ODS1 5 80 220 6.2 no noWaters Spherisorb ODS2 5 80 220 11.5 yes noWaters Spherisorb ODSB 5 80 220 11.5 yes noXTerra MS C18 5 125 - 15.5 yes —YMC J’Sphere ODS H80 4 80 510 22 yes noYMC J’Sphere ODS M80 4 80 510 14 yes noYMC ODS A 5 120 300 17 yes noYMC ODS AM 5 120 300 17 yes noYMC Pro C18 5 120 335 16 yes yesZorbax Extend C18 5 80 180 12.5 yes yesZorbax ODS 5 70 330 20 yes noZorbax Rx-C18 5 80 180 12 no yesZorbax SB-C18 5 80 180 10 no yesZorbax XDB-C18 5 80 180 10 yes yes

0 1 2 3 4 5Time (min)

1

2

3

0 1 2 3 4 5 6 7Time (min)

1

2

3

Figure 2

High Purity Silicas Provide Better PeakShape for Basic Compounds

Figure 3

Specifications of C18 Stationary Phases

Mobile Phase: 60% CH3OH, 40% H2OSample: 1. Uracil

2. Pyridine3. Phenol

3

Interaction between cationic compounds and acidic silanolsites on the surface of silica stationary phase supports cancontribute to retention and peak tailing. Phases made withhigh purity silica (less acidic silica) generally can be expectedto provide better peak shape for basic compounds.

Specifications were obtained from manufacturer’s literature.

Acidic Silica (Waters Spherisorb ODS2)

High Purity Silica (ACE C18)

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Inertsil ODS3

LiChrospher RP-18

ACE C18-HL

YMC J’Sphere ODS H80

Nucleosil C18

Kromasil C18

Develosil ODS-MG

Partisil ODS2

LiChrosorb RP-18

Symmetry C18

Inertsil ODS

Develosil ODS-UG

Purospher RP18-e

YMC Pro C18

Prodigy ODS3

Zorbax ODS

Nucleosil C18HD

SunFire C18

YMC ODS AM

YMC ODS A

Inertsil ODS2

Cosmosil C18-AR

Prodigy ODS2

TSK ODS-80TM

ACE C18

Luna C18(2)

Gemini C18

Genesis C18

Nucleosil C18AB

Waters Spherisorb ODS2

Zorbax Extend C18

Develosil ODS-HG

Resolve C18

Zorbax RX C18

Zorbax XDB C18

Waters Spherisorb ODSB

Hypersil BDS C18

Hypersil HyPurity C18

Ultrasphere ODS

TSK ODS-120T

Partisil ODS3

Hichrom RPB


µBondapak C18

Exsil ODS

Capcell Pak AG C18

YMC J’Sphere ODS M80

Capcell Pak UG C18

Zorbax SB C18

Exsil ODSB

XTerra MS C18

ACE C18-300

Hypersil ODS

Hypersil GOLD

Novapak C18

Exsil ODS1

Vydac SelectaPore 90M

Vydac SelectaPore 300P

Vydac 218TP

Partisil ODS

Vydac 218MS

Vydac SelectaPore 300M

Figure 4

C18 Phase Compared According to Relative Hydrophobicity

Mobile Phase: 90% CH3OH, 10% H2OElution Order: 1. Dimethyl phthalate

2. Toluene3. Biphenyl4. Phenanthrene

Column Temperature: 24°C

Phases Compared According to Relative HydrophobicityHydrophobicity is measured as the retention of a hydrophobic solute, phenanthrene.Figure 4 gives a comparison of hydrophobicity with the C18 phases listed according to hydrophobicity. Notice, however, that the retention for dimethyl phthalate, the least hydrophobic solute in the mixture, cannot always be predicted from thehydrophobicity ranking. Some low hydrophobicity phases actually have greater retention for dimethyl phthalate than some high hydrophobicity phases.We find thatthis is not unusual when separating polar compounds. Phases that are significantlymore retentive for hydrophobic analytes may show only slightly more retention forpolar compounds than low hydrophobicity phases, and sometimes they show less.

4 www.ace-hplc.com

0.0 0.5 1.0 1.5 2.0 2.5

Kromasil C18

Purospher RP-18e

Inertsil ODS3

k (Toluene)

YMC J'Sphere ODS H80

Nucleosil C18

Inertsil ODS2

Genesis C18

Zorbax Extend C18

Luna C18(2)

LiChrospher RP-18

Zorbax ODS

Prodigy ODS3

Symmetry C18

Develosil ODS-MG

SunFire C18

Nucleosil C18AB

Exsil ODS

Develosil ODS-HGLiChrosorb RP-18

Hichrom RPB


TSK ODS-80TM

Zorbax SB-C18

Resolve C18

Ultrasphere ODS

Cosmosil C18-AR

Capcell Pak AG C18

XTerra MS C18

YMC ODS AM

YMC Pro C18

YMC ODS A

ACE C18

Partisil ODS2

Inertsil ODS

Zorbax Rx C18

Develosil ODS-UG

Prodigy ODS2

Zorbax XDB-C18

Nucleosil C18 HD


ACE C18-300

Vydac Selectapore 90M


Hypersil HyPURITY C18

Partisil ODS3

TSK ODS-120T

Hypersil BDS

Hypersil ODS

Hypersil GOLD

Partisil ODS


Vydac Selectapore 300P

Vydac 218TP

Vydac 218MS

Exsil ODSB

µBondapak C18

Exsil ODS1

Novapak C18

YMC J'Sphere ODS M80

ACE C18-HL

Gemini C18

Capcell Pak UG 120

Mobile Phase: 80% CH3OH20% 25mM KH2PO4, pH 6.0

Sample: TolueneTemperature: 24°C

Figure 5

C18 Phases Ranked According toRetention for Toluene

Alternative Test forHydrophobicityToluene can also be used as a probe to measure hydrophobicity. Notice that the ranking of C18 phases according to retention for toluene(Figure 5) is slightly different from the ranking according to retention for phenanthrene (Figure 4).

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6

0 20,000 40,000 60,000 80,000 100,000 120,000N/Meter (Toluene)

ACE C18-300

Zorbax SB-C18

YMC Pro C18

ACE C18

Exsil ODS1

Hypersil GOLD C18

Vydac 218MS

Ultrasphere ODS

Cosmosil C18-AR


LiChrospher RP-18Zorbax Extend C18


Exsil ODSB

YMC ODS AM

Nucleosil C18 HD

Develosil ODS-HG

Zorbax ODS

Nucleosil C18AB

Luna C18(2)

Zorbax Rx-C18



Develosil ODS-UG

Symmetry C18

Exsil ODS

Hypersil ODS

Zorbax XDB-C18

Hichrom RPB

Kromasil C18

YMC ODS A


SunFire C18

Nucleosil C18

Hypersil BDS C18

Capcell Pak UG C18


Novapak C18

Inertsil ODS3

TSK ODS-80TM

Prodigy ODS3

Vydac 218TP


Develosil ODS-MG

Genesis C18Hypersil HyPURITY C18

Inertsil ODS

LiChrosorb RP-18

Inertsil ODS2

µBondapak C18

Partisil ODS2

Purospher RP18-e

Resolve C18

XTerra MS C18

Partisil ODS

Prodigy ODS2

Capcell Pak AG C18

Partisil ODS3


TSK ODS-120T

ACE C18-HL

Gemini C18

Comparison of Column Efficiencyfor a Neutral CompoundColumn efficiency is reported as plates per meter (N/Meter). Using a neutral compound (toluene) for themeasurement greatly reduces the effects of secondary retention on themeasurement of N and allows us toobtain data that is a better indication of the following factors:

• Particle sizeSmaller average packing particle size =Larger N

• Particle size distributionBroader particle size distribution =Smaller N

• Packing efficiencyBetter packing procedures = Larger N

Figure 6

Comparison of Column Efficiencyfor a Neutral CompoundColumn efficiency reported as Plates permeter (N/Meter)

Mobile Phase: 90% CH3OH10% H2O

Sample: TolueneTemperature: 24°C

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Independently PerformedComparison TestsThere are numerous suggestions fromdifferent scientific groups about how to best characterize stationary phases.Most of these tests have merit, but thefact that the ranking of columns willoften differ among the different testsshows the difficulty in devising a definitive test that will predict columnbehavior in all, or even most circum-stances.The National Institute ofStandards & Technology (NIST) hasdeveloped test conditions (StandardReference Material 870) that do a particularly good job of characterizingstationary phases according to metalactivity and silanol activity.

The presence of metals on the surface ofstationary phases can have a significanteffect on chromatographic performance.Even trace levels of metal impurities can contribute to peak tailing of somecompounds. In addition, subtle lot-to-lotvariations in the amount of trace metalsare another cause of poor column reproducibility.The NIST test uses peak asymmetry of quinizarin, a strongmetal chelating agent, to measure metal activity. Figure 7 ranks stationary phases according to metal activity using the NIST test.

To test silanol activity, the NIST test uses amitriptyline, as does the test usedto generate the data in Figure 11.However, the NIST test specifies a mobile phase pH of 7.0 rather than 6.0,and measures peak asymmetry ratherthan plate count to determine silanolactivity.The lower the asymmetry valueof the amitriptyline peak (less tailing) the less silanol activity. Figure 8 ranks stationary phases according to silanolactivity using the NIST test.

Partisil ODS2

µBondapak C18

Novapak C18

Nucleosil C18


Luna C18(2)

Zorbax SB-C18

Discovery C18


Symmetry C18

Inertsil ODS2

Hypersil BDS-C18

Inertsil ODS3

Cosmosil C18 AR-II

XTerra MS C18

Hypersil Elite C18

Zorbax XDB-C18

ACE C18

1.0 1.5 2.0 2.5 3.0 3.5

Peak Asymmetry

HigherMetalActivity

LowerMetalActivity

1.07

3.07

2.56

2.42

2.41

2.27

1.46

1.43

1.37

1.34

1.31

1.27

1.26

1.24

1.16

1.12

1.09

1.07

Figure 7

Comparison of Metal Activity Using the NIST Test: Asymmetry for Quinizarin

Mobile Phase: 80% CH3OH20% 5mM Potassium

Phosphate, pH 7.0Sample: QuinizarinFlow Rate: 2 mL/minTemperature: 23°C

Cosmosil C18 AR-II


Partisil ODS2

µBondapak C18

Novapak C18

Nucleosil C18

Luna C18(2)

Zorbax SB-C18

Discovery C18


Symmetry C18

Inertsil ODS2

Hypersil BDS-C18

Inertsil ODS3

XTerra MS C18

Hypersil Elite C18

Zorbax XDB-C18

ACE C18

1 2 4 6 8 10

Peak Asymmetry

HigherSilanolActivity

LowerSilanolActivity

8.99

8.3

6.50

3.19

3.07

3.05

3.05

2.74

2.21

2.07

1.93

1.88

1.78

1.61

1.52

1.26

1.03

1.12

Figure 8

Comparison of Silanol Activity Using the NIST Test: Asymmetry for Amitriptyline

Mobile Phase: 80% CH3OH20% 5mM Potassium

Phosphate, pH 7.0Sample: AmitriptylineFlow Rate: 2 mL/minTemperature: 23°C

Data obtained from the National Institute of Standards and Technology (NIST), USA. Certificate of Analysis for Standard Reference Material SRM 870, “Column Performance Test Mixture for Liquid Chromatography”.

7www.ace-hplc.com

8

SunFire C18

Hypersil GOLD

ACE C18-300

YMC Pro C18

Develosil ODS-UG

ACE C18

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000N/Meter (Pyridine)

Develosil ODS-MG

Exsil ODSB

Capcell Pak UG C18

Develosil ODS-HG

Zorbax XDB-C18

Inertsil ODS


Inertsil ODS3

Nucleosil C18AB

Partisil ODS2

Vydac 218TP

Vydac 218MS


LiChrosorb RP-18


Cosmosil C18-AR

TSK ODS-80TM

Novapak C18

Prodigy ODS2

Partisil ODS

Zorbax SB-C18

Nucleosil C18



Inertsil ODS2

Purospher RP18-e


µBondapak C18

Prodigy ODS3

Partisil ODS3

Zorbax Rx-C18

Genesis C18

Kromasil C18

TSK ODS-120T

XTerra MS C18


YMC ODS AM

Nucleosil C18 HD

Luna C18(2)

Zorbax Extend C18

YMC ODS A

Resolve C18

LiChrospher RP-18

Hypersil ODS

Zorbax ODS


Exsil ODS

Exsil ODS1

Hypersil BDS C18


Ultrasphere ODS

Symmetry C18

Capcell Pak AG C18

Hichrom RPB

Gemini C18

ACE C18-HL

Comparison of ColumnEfficiency for a Basic CompoundMeasuring column efficiency using aneutral compound is not very useful inpredicting column performance whenseparating ionic compounds. Interactionbetween polar solutes and silanol siteson the stationary phase can cause tailingpeaks and poor column efficiency.Togain a better understanding of columnperformance with basic compoundscolumns were tested using pyridine and amitriptyline as probes.Althoughcolumns are ranked somewhat differently on the two tests, phases at the higher end of the ranking scalecan be expected to give better peakshape and higher resolution for basiccompounds than phases at the lowerend of the scale. Not surprisingly,stationary phases that use high puritysilicas exhibit better peak shape andhigher column efficiency than stationaryphases that use more acidic silicas astheir stationary phase supports.

Figure 9Comparison of Column Efficiencyfor a Basic Compound: Pyridine


Sample: PyridineTemperature: 24°C

ACE

Hypersil HyPURITY

Symmetry

Figure 10

Comparison of Peak Shape


Sample: PyridineTemperature: 24°C

ACE C18 gave the best peak shape and highest columnefficiency for pyridine.

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9

ACE C18 ACE C18-300 SunFire C18

Zorbax XDB C18 Gemini C18 Inertsil ODS3V

Luna C18(2) XTerra MS C18 Zorbax SB C18

Symmetry C18 Hypersil BDS C18 Zorbax ODS

1

2

3

1

2

3

1

2

3

65,200pl/m 52,100pl/m 46,500pl/m

1

2

3

1

2

3

1

2

3,100pl/m 600pl/m 100pl/m

1

2

3

1

2

3

1

3

21,900pl/m 18,600pl/m 10,000pl/m

1

2

3

1

2

3

1

2

3

39,400pl/m 36,100pl/m 35,900pl/m

Comparison of Column Efficiency For a Basic Compound: Pyridine

Column Dimensions: 250 x 4.6mm, 5µm Sample: 1) uracil 2) pyridine 3) phenolMobile Phase: 60:40 MeOH/H2O Temperature: 24°C Flow 1.0ml/min

Column efficiency measured at 10% pyridine peak height to account for peak tailing effects

3

2

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10

SunFire C18

ACE C18-300

Develosil ODS-HG

Zorbax XDB-C18

Hichrom RPB

Develosil ODS-MG

Hypersil GOLD

YMC Pro C18

Develosil ODS-UG

ACE C18

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000

N/Meter (Pyridine)

ACE C18Hypersil GOLD

SunFire C18

Luna C18(2)Develosil ODS-UG

YMC Pro C18


ACE C18-300

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000

N/Meter (Amitriptyline)

ACE C18-HLGemini C18

Hypersil GOLD


ACE C18-300

ACE C18

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000N/Meter (Amitriptyline)

Zorbax ODS

Resolve C18

Partisil ODS2

Hypersil ODS

Exsil ODSCosmosil C18-AR

Capcell Pak AG C18

Ultrasphere ODS

Zorbax Rx-C18

Nucleosil C18

µBondapak C18

LiChrosorb RP-18Partisil ODS3

Partisil ODS


LiChrospher RP-18

Vydac 218TP

TSK ODS-120T


TSK ODS-80TM

Novapak C18

Exsil ODSB

Inertsil ODS

Zorbax SB-C18

Exsil ODS1

Vydac 218MS


Zorbax Extend C18

SunFire C18

YMC ODS AM

Zorbax XDB-C18

YMC ODS A

Nucleosil C18AB

Kromasil C18

Genesis C18

Purospher RP18-e

Develosil ODS-HG

Symmetry C18Hypersil BDS C18

XTerra MS C18


Capcell Pak UG C18

Prodigy ODS2

Develosil ODS-MG

Inertsil ODS3

Nucleosil C18 HD

Hichrom RPB

Prodigy ODS3

Luna C18(2)

Develosil ODS-UG

YMC Pro C18





Inertsil ODS2

ACE C18-HL

Gemini C18

Figure 11

Comparison of Column Efficiency for aBasic Compound: Amitriptyline

Plate count is measured at 10% ofpeak height to include peak tailing inthe calculation. Both tests use mobilephases at neutral pH to encourageinteraction between the basic probesand silanols on the stationary phase.

Figure 12

Top 10 Columns Ranked According toPeak Shape and Efficiency

Mobile Phase: 80% CH3OH20% 0.025M KH2PO4, pH 6.0

Sample: AmitriptylineTemperature: 24°C

Sample: AmitriptylineMobile Phase: 80% CH3OH

20% 0.025M Phosphate, pH 6.0

Sample: PyridineMobile Phase: 60% CH3OH

40% H2O

Note: All columns are packed with5 micron size material.

Column ranking does differ in the two tests of columnefficiency for a basic compound (Figures 9 and 11).However, of the 14 columns that ranked in the top 10on at least one of the tests, 6 ranked in the top 10 onboth tests.

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11

Comparison of Column Efficiency For a Basic Compound: Amitriptyline

Column Dimensions: 250 x 4.6mm, 5µm Sample: 1) norephedrine 2) nortriptyline 3) toluene 4) imipramine 5) amitriptylineMobile Phase: 80:20 MeOH/0.025M KH2PO4 Temperature: 24°C Flow 1.0ml/min

Column efficiency measured at 10% amitriptyline peak height to account for peak tailing effects

ACE C18-300 ACE C18 Gemini C18

SunFire C18 Luna C18(2) Inertsil ODS3V

Hypersil HyPURITY C18 XTerra MS C18 Hypersil BDS C18

Symmetry C18 Zorbax SB C18 Waters Spherisorb S5ODS2

1

2

3

4 5

1

23

4

5

1

2

3

45

65,300pl/m 63,300pl/m 48,500pl/m

1

2

3

45

1

2

3

4 51

2

3

45

21,800pl/m 4,900pl/m 1,300pl/m

1

2

3

45

1

23

45

1

2

3

4

5

24,800pl/m 24,400pl/m 22,700pl/m

1

2

3

4

5

1

2

3

4

5

1

2

34

5

45,000pl/m 43,200pl/m 30,500pl/m

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Phases Grouped According toSilanol ActivityAmitriptyline and pyridine are both goodtest probes to use for measuring silanolactivity of stationary phases. Even a smallamount of silanol exposure by the stationary phase can cause measurablepeak broadening and peak asymmetrydeterioration on one or both of thesecompounds. Chromatographic testsusing these two probes are the primarymeasurements used to group these C18phases according to silanol activity(Figure 13).

Columns classified as having “very low”silanol activity appear in the Top 10 rankings on both the pyridine andamitriptyline tests (Figure 12).

In general, phases identified as having“very low” silanol activity will give thehighest column efficiency in the pyridineand amitriptyline tests (Figures 8, 9 &10).

Benefits of Using Ultra-InertStationary PhasesPhases identified as having “very low”silanol activity may also be identified as“ultra-inert” or “ultra-pure” due to theelimination of undesirable secondaryinteractions between the sample andsilanol groups on the silica.

In addition to the previously highlightedbenefits of improved peak efficiency and asymmetry, the elimination of unpredictable silanol interactions significantly improves stationary phasereproducibility.

Material Silanol Activity

ACE C18ACE C18-300Develosil ODS-UGHypersil GOLDSunFire C18YMC Pro C18

ACE C18-HLCapcell Pak UG C18Develosil ODS-HGDevelosil ODS-MGGenesis C18Gemini C18Hichrom RPBHypersil HyPURITY C18Inertsil ODS3Kromasil C18Luna C18(2)Nucleosil C18 HDProdigy ODS2Prodigy ODS3Purospher RP18-eSymmetry C18XTerra MS C18YMC ODS AYMC ODS AMZorbax Extend C18Zorbax XDB-C18

Capcell Pak C18 SGCosmosil C18-ARExsil ODSBHypersil BDS C18Inertsil ODSInertsil ODS2Nova-Pak C18Nucleosil C18ABPartisil ODS3Synchropak CR101TSK ODS-120TTSK ODS-80TMµBondapak C18Vydac 218MSVydac 218TPVydac Selectapore 300MVydac Selectapore 300PVydac Selectapore 90MWaters Spherisorb ODSBYMC J’Sphere ODS H80YMC J’Sphere ODS M80Zorbax Rx-C18Zorbax SB-C18

Capcell Pak C18 AGExsil ODSExsil ODS1Hypersil ODSLiChrosorb RP-18LiChrospher RP-18Nucleosil C18Partisil ODSPartisil ODS2Resolve C18Ultrasphere ODSWaters Spherisorb ODS1Waters Spherisorb ODS2Zorbax ODS

Very Low

Low

Moderate

High

Figure 13

Grouping of C18 Columns According toSilanol Activity

For further technical information on ultra-inert HPLCcolumns please contact your local distributor;

www.ace-hplc.com

ACE Comparison Guide - Analítica · 2 This Guide provides the following comparison data on...

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