View
6
Download
0
Category
Preview:
Citation preview
Polymer Coated Titania for Analytical and Preparative Reversed-Phase Chromatography
Pittcon 2005CLAYTON V. MCNEFF1, BINGWEN YAN1, JOCHEN WINKLER2
1ZirChrom Separations, Inc., 617 Pierce Street, Anoka, MN 553032 Sachtleben, Duisburg, Germany
1-866-STABLE-1www.zirchrom.com
Outline• Properties of Titania
• RP Phase Stationary Phase
• Chromatographic Data
• Selectivity Comparison of Sachtopore-RP, Silica C18, ZirChrom-CARB, and ZirChrom-PBD
• Effect of Lewis Base Mobile Phase Additive on Elution of Basic Compounds
• Chemical and Thermal Stability TestingConclusion - The Sachtopore®-RP shows very similar selectivity to ZirChrom®-PBD and has excellent stability from pH 1-12 and up to 100 oC.
Element Electronic Structures
• Silicon (element 14; 2.3 g/cc; Si4+ ionic radius 0.400 Å)– Ne3s23p2
• Titanium (element 22; 4.5 g/cc; Ti4+ ionic radius 0.605 Å)– Ar3d24s2
• Zirconium (element 40; 6.5 g/cc; Zr4+ ionic radius 0.720 Å)– Kr4d25s2
All have four valence electrons so some chemistry is similar, but presence of d orbitals and very electropositive nature allow Ti and Zr (metals) to form strong electron donor-acceptor complexes (coordination chemistry).
Surface Chemistry of Titania-Based Supports for HPLC
Ti Ti
O
OTi Ti
O
OTi Ti
O
OTi Ti
O
O
O
OO
O
O
O
O HO
O H H2O O H2 H2OO H
Weak Brönsted Base: Ti Ti
O
O
O
H++ ⇔Ti Ti
O
O
O
H
Weak Brönsted Acid: OHTiOOHTiOH 2+⇔+−−
Strong Lewis Acid: Ti
O
O
O
OP
O
OO
O
⇔+ SCX modeTi
O
O
O
O
P
OO O
O -
Titania Crystal FormsAnatase (tetragonal), 300 oCRutile (tetragonal), 600 oCBrookite (orthorhombic), 850 oC.
AnataseRutile
Crystallographic data and pI values of sorbents
SiO2 TiO2 Al2O3 ZrO2Ionisation potential (V) 45.14 (Si4+) 43.27 (Ti4+) 28.45 (Al3+) 34.34 (Zr4+)Coordination number 4 6 6 7Ion radius (A) 0.41 (Si4+) 0.68 (Ti4+) 0.5 (Al3+) 0.8 (Zr4+)Ionisation potential/coordination number (V) 11.29 7.33 4.74 4.83pI of sorbent (pH) 2.2 6.6 8.1 6Porosities of test columns (%) 73 74 79 69
Polyethylene Coated Titania
Ti Ti
O
OTi Ti
O
OTi Ti
O
OTi Ti
O
O
O
OO
O
O
O
O HO
O H H2O O H2 H2OO H
PolyethyleneCH2-CH2[ ]n
22 Non-electrolyte Solutes
Benzene Toluene Ethylbenzene p-xylene Propylbenzene Butylbenzene
Br Cl
Cl
OO
O
CN NO2 NO2Cl
NO2
OBromobenzene p-Dichlorobenzene Anisole Methylbenzoate Naphathalene Acetonphenone
Benzonitrile Nitrobenzene p-Nitrotoluene p-Nitrobenzyl Chloride
O
Benzophenone
OH OH NH H
OOH OH
Cl
Benzylalcohol 3-Phenyl Propanol N-Benzyl Formamide Phenol p-Chlorophenol
Nonpolar
Polar
HB Donor
Selectivity Comparison
LC Conditions: Mobile phase, 40/60 ACN/Water; Flow rate, 1.0 ml/min.; Temperature, 30 oC; Injection volume, 5ul; Detection at 254nm.
Solute
-1.500
-1.000
-0.500
0.000
0.500
1.000
1.500
2.000
benz
yl for
mami
de
benz
yl alc
ohol
phen
ol
3-phe
nyl p
ropan
ol
p-chlo
rophe
nol
aceto
phen
one
benz
onitri
le
nitrob
enze
ne
methy
lbenz
oate
aniso
le
p-chlo
rotolu
ene
p-nitro
benz
yl ch
loride
benz
ophe
none
bromo
benz
ene
naph
thalen
ep-x
ylene
p-dich
lorob
enze
nebe
nzen
etol
uene
ethyl
benz
ene
propy
l ben
zene
butyl
benz
ene
log
(k' S
olut
e/k'
ben
zene
)
ZirChrom-PBDZirChrom-CARBSilica C18Sachtopore®-RP
κ-κ Comparison
LC Conditions: Mobile phase, 40/60 ACN/Water; Flow rate, 1.0 ml/min.; Temperature, 30 oC; Injection volume, 5ul; Detection at 254nm.Reference: Melander, W.; Stoveken, J.; Horvath, C. J. Chromatogr. 1980, 199, 35-56.
R2 = 0.992
R2 = 0.036
R2= 0.911
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
0.00 1.00 2.00 3.00 4.00 5.00k' (Schtopore RP)
k' (P
BD
, CA
RB
, C18
) Sachtopore®-RP vs ZirChrom-PBD
Sachtopore®-RP vs ZirChrom-CARBSachtopore®-RP vs Silica-C18
Chemical Stability
Exposure and Evaluation Conditions: Mobile phase, 15/85 ACN/0.1M Nitric acid, pH 1.0, or 0.01M Tetramethylammoniumhydroxide, pH 12.0; Flow rate, 1.0 ml/min.; Temperature, 30 oC; Injection volume, 5 µl; Detection at 254 nm; Column, 50 mm x 4.6 mm i.d. Sachtopore®-RP .
pH 1.0
0.0
2.0
4.0
6.0
0 1000 2000 3000 4000 5000
Column Volumes
k'
methyl benzoate
anisole
Benzonitrile
toluene
pH 12.0
0.0
2.0
4.0
6.0
0 1000 2000 3000 4000 5000
Column Volumes
k'
toluene
anisole
Benzonitrile
Methyl benzoate
Temperature Stability at 100 oC
Exposure and Evaluation Conditions: Mobile phase, 15/85 ACN/water; Flow rate, 1.0 ml/min.; Temperature, 100 oC with Metalox heater; Injection volume, 5 ml; Detection at 254 nm; Column, 50 mm x 4.6 mm i.d., Sachtopore®-RP .
0.0
1.0
2.0
3.0
0 1000 2000 3000 4000 5000 6000
Column Volumes
k'
toluene
anisole
Benzonitrile
methyl benzoate
Effect of Lewis Base Additive on Separation of Basic Drugs
Chromatographic Conditions: Column 50X4.6 mm Sachtopore®-RP, Mobile phase: 30/70 ACN/20 mM buffer (pH=7). (A) ammonium acetate, (B) ammonium fluoride, (C) ammonium phosphate. flow rate: 1ml/min, temperature: 40 oC. Wavelength: 254 nm. Solutes: (1) lidocaine, (2) quinidine, (3) tryptamine, (4) amitriptyline, and (5) nortriptyline.
min0 2 4 6 8 10 12 14 16 18
1 3
2 4
5
1 3
2
4
4
5
5
2+3
1
A
B
C
Effect of Ionic Strength on Separation of Basic Drugs
min0 2.5 5 7.5 10 12.5 15 17.5 20 22.5
45
2+3
1
1 32
45
1 32 4 5
(A) 10 mM
(B) 15 mM
(C) 20 mM
Chromatographic Conditions: Column 50X4.6 mm Sachtopore®-RP , Mobile phase: 30/70 ACN/phosphate buffer (pH=7). (A) 10 mM, (B) 15 mM, (C) 15 mM. flow rate: 1ml/min, temperature: 40 oC. Wavelength: 254 nm. Solutes: (1) lidocaine, (2) quinidine, (3) tryptamine, (4) amitriptyline, and (5) nortriptyline.
Antihistimines Separation at pH 10
-5,0
0,0
10,0
20,0
30,0
40,0
45,0
0,0 2,0 4,0 6,0 8,010,0 12,0 15,0
mAU
min
1
2
3
4
5
230 nm
NH 3 C
O
4: Diphenylpyraline
ON
C H 3
C H 3
5: Phenyltoloxamine
H
H
C O O H
C O O H
1: maleic acid
N
ON
C H 3
C H 3
C l
2: Carbinoxamine
N
NH 3 C
C H 3C l
3: Chlorphenamine
LC Cconditions: Mobile phase, 74% (50 mM H3PO4 + 5 mM KH2PO4), 26% ACN, pH 10; Flow rate, 1.0 ml/min.; Temperature, Ambient; Injection volume, 20 µl; Detection at 220 nm; Column, Sachtopore®-RP (300 Å, 3 µm, 150x4 mm).
Separation of Basic Cardiac Drugs at pH 10
-1,0
5,0
10,0
15,0
20,0
25,0
33,0
0,0 2,0 4,0 6,0 8,0 10,0 12,0 15,0
mAU
min
1
2
3
4
5
6
7
230 nm
N
N
N
N
N
H 3 C
C H 3H 3 C
1: Trapidil
O
O H
HN C H
3
C H3
H3
C O
2: Metoprolol
N
NN
N
N
N
N
NO H
O H
H O
H O
5: DipyridamoleHN
O C H 3
O
H 3 C O
ON O 2
H 3 C C H 3
3: NifedipineO
ON C H 3
C H 3
I
I
O
C H 3
4: AmiodaroneO
O
N C H 3H 3 C
7: Etafenone
NH 3 C O
H 3 C O
C N
C H 3
H 3 CC H 3
O C H 3
O C H 3
6: Verapamil
LC Cconditions: Mobile phase, 70% (10 mM Borax + 10 mM Soda), 30% ACN, pH 10; Flow rate, 1.0 ml/min.; Temperature, Ambient; Injection volume, 20 µl; Detection at 230 nm; Column, Sachtopore®-RP (300 Å, 3 µm, 150x4 mm).
Semi-Prep Separation of Pentifylline (vasodilator)
-200
0
250
500
750
1000
1250
1500
1800
0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0
mAU
min
SLB16 #69 A15 UV_VIS-1280 nm
LC Cconditions: Mobile phase, (+ 10 mM Na2B4O7 + 1 mM H3BO3), pH 8.8; Flow rate, 1.0 ml/min.; Temperature, Ambient; Injection volume, 20 µl; Detection at 254 nm; Column, Sachtopore®-RP (300 Å, 3 µm, 150 x 4 mm).
Particle Sizes:3,5,10,20,40,80100 micron1 mm
Pores sizes:60, 100, 300, 500, 1000, 2000 Angstroms
Conclusions
• The Sachtopore®-RP shows similar selectivityto ZirChrom®-PBD (ODS-like for neutrals).
• The Sachtopore®-RP has excellent stabilityfrom pH 1-12 and up to 100 oC.
• The type of Lewis base buffer has a profound effect on selectivity for Sachtopore®-RP.
• Basic (amine) analytes generally undergo RP/CEX mixed-mode retention mechanism onSachtopore®-RP.
Acknowledgments
For more information and web access to the free Buffer Wizard: www.zirchrom.com
®
1-866-STABLE-1www.zirchrom.com
Dr. Jochen Winkler – Sachtleben
Dr. Bingwen Yan - ZirChrom
Visit Us at Booth 2801
Recommended