Development of Superficially Porous Silica with Polyfunctional C18 Bonding
Technique for Reversed Phase HPLC
www.chromanik.co.jp

Norikazu Nagae1), Tomoyasu Tsukamoto1), Harald Dibowski2, Annette Dibowski2,Anders Grahn3), Ralf Jutvik3) and Vinay D. Gaintonde3)

1) ChromaNik Technologies Inc., 6-3-1 Namiyoke, Minato-ku, Osaka, Japan2) dichrom GmbH, Gräwenkolkstraße 66, 45770 Marl, Germany 3) Biotech AB, Box 133, 439 23, Onsala, Sweden

www.biotech-sweden.com

0.5 mmAbstract

0.5 mmBrand columns packed with superficially porous particles have been available for sometime. The superficially porous media or so called core-shell media offers significant
improvements such as higher efficiency and lower pressure drop for existing HPLC operations
without having to replace existing HPLC systems with UHPLC systems.
In this study, core-shell silica bonded with C18 using polyfunctional bonding technique(SunShell C18) was evaluated. A 2.6 μm core-shell silica with a non-porous core approximately
1.6 μm in diameter and a superficially porous layer of 0.5 μm was used to be bonded withhexamethyloctadecyltetrasiloxane (HMODTS) and end-capped with trimethylsilane.
Proposed core-shell C18 yielded efficiencies close to totally porous sub-2 μm or 2 μm C18
and showed less than half the pressure drop to compare with the sub-2 μm or 2 μm C18.
Stability under both acidic and basic pH conditions as well as peak shape of basic, acidic andmetal-chelating compounds were evaluated and compared with other core-shell typecolumns. Proposed core-shell C18 was more stable than the other core shell C18s under acidic
and basic pH conditions.
Loading capacity of amitriptyline was examined in acid, low-ionic-strength mobile phasessuch as a mixture of 0.1% formic acid and acetonitrile and 20 mM phosphate buffer pH7.0 andacetonitrile.

35

Fully porous 3 um

30

Brand C C18 1.7 um

25

Brand D C18 2.6 um

12

Fully proous 1.8 um

10SunShell 2.6 um

860SiMeClMeMe
SiO

2468

10

1214

0.2

0.4

0.6

OMeOMe

Si

0.8

1

1.2

1.4OSiOSiOOSi

Brand K core shell C18
Brand A core shell C18
SunShell C180.1

1100Sample weight/mg , mg

1234567Retention time/min

891

1.6

405108060
Brand K core shell C18
Brand A core shell C18
SunShell C18

200204060Time (h)80100120

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

Figure 8. Stability under acidic pH condition

Conclusion

1Core shell silica C18
SunShell C18 2.6 mm

540Retention
time (ｔR)
1.35
1.47
1.65
10.01
14.24
15.09
20.33725Column: SunShell C18, 2.6 mm
100 x 2.1 mm
Mobile phase: CH3CN/H2O=60/40
Flow rate: 0.3 mL/min
Pressure: 12.5 MPa
Temperature: 25 ºC

446Sample: 1 = Uracil
2 = Toluene
3 = Acenaphthene
4 = BUtylbenzene

815 min6Plates(3)=38,000

243

In the case of using acetonitrile /0.1% formic acid as a mobile phase, amitriptyline peak shows more
tailing because a loading capacity decreases in an acidic, low-ionic-strength mobile phase.

Durable 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

8060
Brand K core shell C18
40

2SunShell C18

00

1,000

2,000

3,000

4,000

Elution volume (mL)

5,000

6,000

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

Figure 9. Stability under basic pH condition

6Column: SunShell C18, 2.6 mm
150 x 4.6 mm
Mobile phase: CH3CN/H2O=70/30
Flow rate: 1.0 mL/min
Pressure: 11.5 MPa
Temperature: 25 ºC

810

Retention time/minFigure 7. Chromatogram of standard samples of SunShell C18＋Q1: 5.997 min to 7.999 min of Sample

TIC of ＋Q1

Brand A core shell C18

20

4Retention
factor (k)
00.10
0.18
3.55
4.99
5.43
5.94

30

Retention time/min

4Retention
time (ｔR)
1.36
1.49
1.61
6.19
8.15
8.75
9.44

Mobile phase: Methanol/water(75:25)
Temperature: 40oC
Column dimension: 150 x 4.6 mm
Flow rate: 1.0 mL/minPlates(3)=21,300

1100

Effective 200 m2/g

Retention
factor (k)00.090.226.41
9.55
10.18
14.06

61520Retention time/min2Core shell silica C18Kinetex C18 2.6 mm

150 m2/g

Retention
factor (k)
00.12
0.28
6.85
10.29
10.74
13.32
720Durable 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 ºC

SiFigure 6. Loading capacity of amitriptyline II

4.4%100OSi OSi3

1.3
0.01
0.1
Sample weight, mgOO62 3 Sunniest C18 5 mm
11.8

10.001SiOO O

340 m2/g

Retentiontime (ｔR)
1 = Uracil
1.70
2 = Caffeine
1.90
3 = Phenol
2.17
4 = Butylbenzene
13.35
5 = o-Terphenyl
19.19
6 = Amylbenzene
19.96
7 = Triphenylene
24.35
2 3 SunShell C18 2.6 mm 52.4

7 timesOOO

O O Si Si
SiOO OHOSi OOOSiSiSi
HO O
O O
OO O
O O
SiOSiOOSiSiSi
O O
O Si
Si O O O
OOOOOSiSi O

Fully porous silica C18Sunniest C18 5 mm
Specific surface area

10Figure 5. Loading capacity of amitriptyline I40

2.92.5

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

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

SunShell C18

1.5

Brand ACore Shell
C18

Relative plate of butylbenzene(%)

0.01

3.6

2

Brand KCore Shell
C18

2000
00.001

USP tailing factor

100 times

10000

Brand A Core Shell C18O

Si

SiO

SiO

Si

Table 1. Comparison of retention between fully porous silica
C18 and core shell silica C18s

USP Tailing factor

Brand k Core Shell C18

3SiSiOOOOOMobile phase: Acetonitrile/0.1% formic acid=(30:70)
Column dimension: 150 x 4.6 mm, Flow rate: 1.0 mL/min, Temp.: 40oC

3.5SiO

Figure 2. Schematic diagram of bonding of SunShell C18 （Core Shell particle）

Figure 4. Comparison of Back Pressure for HighThroughput Columns

SunShellC1812000

OO
Si

4140000O

Flow rate, mL/min

Mobile phase: Acetonitrile/20mM phosphate buffer pH7.0=(60:40)
Column dimension: 150 x 4.6 mm, Flow rate: 1.0 mL/min, Temp.: 40oC4000

SiOO

1616000

6000

SiSiSi(HMODTS)

Column dimension: 50 x 2.1 mm
Mobile phase: Acetonitrile/water=(70/30)
Temperature: 25 oC0Figure 3. Comparison of Plate Height Plots

8000

MeMeMeHexamethyloctadecyltetrasilane

0Mobile Phase Velocity, mm/sec

Theoretical plate

SiO

155Column:C18, 50 x 4.6 mm
Mobile phase: Acetonitrile/water=(60/40)
Temperature: 25 oC Sample : Naphthalene

2

Relative retention (%)

HOSunShell C18 2.6 um

104

Final TMS

BondBrand B C18 1.8 um

20Core1.6 mm

Figure 1. Schematic diagram of a core shell silica particle

Brand A C18 1.9 um

Fully porous 5 um

Pressure, MPa

Plate Height, um

142.6 mm

Porous silica

Sunniest C18-HT 2.0 um

4016Core2.6 mm

45180

www.dichrom.com

Brand L C18

SunSell C18

Column size: 50 x 2.1 mm
Mobile phase:A) 0.1% acetic acidB) CH3CN
Gradient:
Time: 0min 1min 5min 7min
%B: 5% 5% 100% 100%
Flow rate: 0.4 mL/min
Temperature: 40 ºC
MS： ABI API-4000
Ionization:
Turboionspray (cation)
Measurement mode:
Q1 Scan m/z 100-1000

Figure 10. Bleeding test using LC/MS*Core shell particle bonded with polyfunctional C18 (SunShell C18) showed 2 times higher retention factor than Kinetex C18.
*SunShell C18 had 7 to 100 times higher loading capacity than the other core shell C18.
*Furthermore, SunShell C18 was not only stable under acidic and basic pH conditions to compare with the other core shell C18s, but also showed lessbleeding under a typical LC/MS condition.