Evaluation of Six Core Shell Columns Based on Both Separation Behavior and Physical Property
Norikazu Nagae, Tomoyasu Tsukamoto, Shun Kojima

ChromaNik Technologies Inc., 6-3-1 Namiyoke, Minato-ku, Osaka, Japanwww.chromanik.co.jp

Abstract

A column packed with 2.7 μm core shell particles has been widely used on HPLC and UHPLC, because it showed not only excellent column efficiency but also lower backpressure than sub-2 μm column. More than 10 kinds of core shellcolumn are available in the market. It is said that two types of core shell silica particle are used. One is a mono-layer structure as a porous silica layer like a core shell silica manufactured by Advanced Materials Technology and anotheris a multi-layer structure like that manufactured by Phenomenex.
In this study, a separation behavior and physical property along with performance matrix of Kinetex C18, Accucore C18, Cortecs C18, PoroShell EC-C18, Ascentis Express C18 and SunShell C18 were evaluated. The evaluation andperformance measurements were done using Tanaka Method with reference to retention factor, hydrogen bonding capacity, hydrophobicity and steric selectivity. In addition to peak shapes profile the core shell columns wereevaluated for loading capacity of amitriptyline under neutral condition. The stability of the core shell columns under acidic pH1 and basic pH10 conditions at elevated temperatures was evaluated. Apart from physical property such as
specific surface area, pore volume, pore diameter along with carbon loading of each C18 packing material, we studied forced degradation of alkyl chains by sintering at 600 degree Celsius for 8 hours. This study revealed significant
differences among 6 kinds of core shell C18 in regards to separation behavior, stability and physical properties. This difference can be attributed to diversity of each manufacturing method and bonding technique as well as fully porous
silica C18 sorbent matrixes. SunShell C18 showed the largest retention factor and the highest stability despite moderate carbon loading (7%), while the company P C18 core shell column which had the lowest carbon loading and thelowest specific surface area revealed the lowest retention factor and the company A C18 core shell column revealed the lowest stability in regards to chromatographic performance and endurance at elevated Temperature and pH.

244765SunShell C18
21.8 MPa 4
68

Hydrogen bonding Hydrophobicity Steric selectivity

30.6 MPa

52 k6=9.7
1 3 N6=31,800

0646(Caffeine/Phenol)

0.48

1.54

1.20

0.35

1.56

1.50

Company W C18

0.38

1.59

1.32

Company A C18

0.42

1.57

1.25

Company S C18

0.44

1.60

1.31

SunShell C18

0.39

1.60

1.46

Company P C18

Company S C18
Company T C18
22.2 MPa
7k6=10.4
N6=31,900

10121416
Retention time/min182022(Amylbenzene/Butylbenzene) (Triphenylene/o-Terphenyl)

24

16000

13

2

TF=1.18

414000100 times

SunShell C18

10000

Company A C18
Sunniest C18 3um
Company P C18
Company T C18
Compnay W C18
Company S C18

8000
6000
4000

TF=2.43

2000

0.1

110

1

2

3

4
5
6
7Retention time/min

Company T C18
2

TF=1.56

Company W C18
2

1

TF=2.07

Company A C18
21Company S C18

TF=2.04
10

1

2
TF=1.21

2

3

4

10Sample: 1=Uracil, 2=Propranolol,
3= Nortriptyline, 4=Amitriptyline
CH3Column:
Company P C18, 2.6 mm 150 x 4.6 mm
Company T C18, 2.6 mm 150 x 4.6 mm
Company W C18, 2.7 mm 150 x 4.6 mm
Company A C18, 2.7 mm 150 x 4.6 mm
Company S C18, 2.7 mm 150 x 4.6 mm
SunShell C18, 2.6 mm 150 x 4.6 mm
Mobile phase: CH3CN/20mM H3PO4=10/90
Flow rate: 1.0 mL/min
Temperature: 40 ºC
Detection: UV@250nm
Sample: 1 = 8-Quinolinol (Oxine)
2 = Caffeine

56712000
10000
8000
6000
4000

100 times

SunShell C18

0.01

89▲

SunShell C1840Company S C18
Company W C18

Measurement condition
Column size: 50 x 2.1 mm
Mobile phase: CH3CN/H2O=60/40
Flow rate: 0.4 mL/min
Temperature: 40 ºC
Sample: 1 = Uracil
2 = Butylbenzene

Company T C18
Company P C18
Company A C18

200020406080100120

CH3Durable test condition
Column size: 50 x 2.1 mm
Mobile phase:
CH3OH/20mM Sodium borate/10mM
NaOH=30/21/49 (pH10)
Flow rate: 0.4 mL/min
Temperature: 50 ºC

1008060

SunShell C18
Company S C18

40Company P C18

Measurement condition
Column size: 50 x 2.1 mm
Mobile phase: CH3OH/H2O=70/30
Flow rate: 0.4 mL/min
Temperature: 40 ºC
Sample: 1 = Butylbenzene

Company T C18

20

Company A C18

01,000 2,000 3,000 4,000 5,000 6,000

Elution volume/mLAcidicBasic condition
condition pH 1 pH 10

200000.001

600Company A C18
Sunniest C18 3um
Company P C18
Company T C18
Compnay W C18
Company S C18

0.1

110Sample weight/mg

SunShell C18

Retention time/min

14000

Theoretical plate

21916000

Company P C18
1 TF=3.94

8N

2

Durable test condition
Column size: 50 x 2.1 mm
Mobile phase: CH3CN/1.0% TFA,pH1=10/90
Flow rate: 0.4 mL/min
Temperature: 80 ºCTime/hS C18(core shell)

TF=4.38

Sample weight/mg▲

W C18(core shell)

TF=3.170.01▲

80T C18(core shell)

TF=3.2100.001

Sunniest
C18 3μm(fully porous)
P C18(core shell)

TF=1.250

TF=1.24

A C18(core shell)

TF=1.42

12000

Metal Chelating Compound
1

SunShell C18(core shell)▲

Sample: 1=Uracil, 2=Propranolol,
3= Nortriptyline, 4=Amitriptyline

10

pH range written ineach brochure

SunShell C18◎◎

1.5 - 10Company W C18△

not tested

2-8Company S C18○○2-9Company A C18△

△2-9Company T C18△△

1 - 11Company P C18△△

1.5 - 10

Physical Property
12aSunSehll C18 (2.54 μm)
aAscentic Express C18 (2.52 μm)
Accucore C18 (2.53 μm) aaKinetex C18 (2.34 μm)
a
PoroShell C18 (2.34 μm)
Cortecs C18 (2.77 μm)a10

Number/%Mobile phase: Acetonitrile/20mM phosphate buffer pH7.0=(60:40)
Column dimension: 150 x 4.6 mm, Flow rate: 1.0 mL/min, Temp.: 40oC

Theoretical plate was calculated by 5σ method
using peak width at 4.4% of peak height

Comparison of Oxine,

Stability under pH1 and 10 Conditions
100

Theoretical plate

3231Loading Capacity of Amitriptyline

75

Relative retention/%

Column:Company P C18, 2.6 μm 150 x 4.6 mm (26.1 Mpa, 30,800 plate )Company P C18
264
Company T C18, 2.6 μm 150 x 4.6 mm (22.7 Mpa, 31,600 plate)
26.1 MPa
11 3
Company W C18, 2.7 μm 150 x 4.6 mm (18.5 Mpa, 23,300 plate)
275
Company A C18, 2.7 μm 150 x 4.6 mm (30.6 Mpa, 30,200 plate)
1k6=7.4
Company T C18
Company S C18, 2.7 μm 150 x 4.6 mm (22.2 Mpa, 31,800 plate)
N6=31,600
63422.7 MPa
SunShell C18, 2.6 μm 150 x 4.6 mm (21.8 Mpa, 31,900 plate)
Mobilephase: CH3OH/H2O=75/25
75
7
1 2 k6=7.75Company
WC18
Flow rate: 1.0 mL/min
N6=23,300 4
6318.5 MPa
Temperature: 40 ºCSample: 1 = Uracil, 2 = Caffeine, 3 = Phenol, 4 = Butylbenzene
7
1 2 k6=9.0
5
5 = o-Terphenyl, 6 = Amylbenzene, 7 = Triphenylene
Company A C18
N6=30,200
k6=5.4N6=30,800

Relative plate of butylbenzene/%

Comparison of Standard Samples

8642012Particle diameter/μm48*Measured using Beckman Coulter Multisizer 3 after C18 materials were sintered at
600 degree Celsius for 8 hours. The measured value of each sintered core shell silica
is considered to be different from that of the original core shell silica.
a. Median particle size

Carbonloading (%)
SunShell C18

Specific surface Pore volume aarea a (m2/g)(mL)

Pore diameter a(nm)7.3 (7)b125 (150)b0.261

Company S C18

8.0133 (150)b0.278

8.20 (9)bCompany A C18

8.5 (8)b135 (130)b0.414

12.3 (12)b8.34 (9)bCompany T C18

8.8 (9)b130 (130)b0.273

8.39 (8)bCompany W C18

7.3 (6.6)b113

0.264

9.32

Company P C18

4.9(12 effectivecarbon loading)b102(200 effectivesurface area)b

0.237

9.25 (10)ba. Measured after C18 materials were sintered at 600 degree Celsius for 8hours. The measured value of each sintered core shell silica is considered
to be smaller than that of the original core shell silica.
b. Value written in each brochure or literature

Comparison of Formic Acid1TF=1.47

Company P C18
Company T C18

TF=3.21
TF=1.460

1132

TF=1.79 1

TF=1.45

321

TF=1.86

32

12Company W C18

Company A C18

233

Company S C18

132SunShell C18
23Retention time/min

456Column:
Company P C18, 2.6 mm 150 x 4.6 mm
Company T C18, 2.6 mm 150 x 4.6 mm
Company W C18, 2.7 mm 150 x 4.6 mm
Company A C18, 2.7 mm 150 x 4.6 mm
Company S C18, 2.7 mm 150 x 4.6 mm
SunShell C18, 2.6 mm 150 x 4.6 mm
Mobile phase: CH3CN/0.1% H3PO4=2/98Flow rate: 1.0 mL/min
Temperature: 40 ºC
Detection: UV@210nm
Sample: 1 = Formic acid
2 = Acetic acid
3 = Propionic AcidConclusion
Used Column Name
1. Company P C18, 2.6 mm: Kinetex c18
2. Company T C18, 2.6 mm: Accucore C18
3. Company W C18, 2.7 mm: Cortecs C18
4. Company A C18, 2.7 mm: PoroShell C18 EC
5. Company S C18, 2.7 mm: Ascentis Express C18
6. SunShell C18, 2.6 mm

The big difference concerning retention, residual silanol groups, metal impurities, loading
capacity, stability and particle size among core shell C18s was confirmed as well as fully
porous C18s.
SunShell showed the longest retention, the most symmetrical peak and the highest stability.
Not only the measured value of physical property but also pH range for usage is not as sameas a value shown in a brochure and a literature in some cases.