New Stable Chemically Bonded Carbon Stationary Phases for HPLC

Transcription

1 New Stable Chemically Bonded Carbon Stationary Phases for HPLC Angelos Kyrlidis, Lynn Toomey, and Elena Khmelnitskaia, Cabot Corporation Dwight Stoll, Clayton V. McNeff, and Peter W. Carr ZirChrom Separations, Inc.

2 Outline Advantages of Stable Phases Development of a New Type of Reversed Phase Column: DiamondBond -C8 Selectivity Comparison of DiamondBond -C8 and Other DiamondBond Phases with ODS Silica Applications Summary

3 Why Stable Phases? Advantages of Extraordinary Chemical Stability ph Stability Thermal Stability ph < ph > 3 Lower Pressure Drop Less Organic Solvent Thermally Optimize Selectivity Clean with conc. Acids Suppress Ions for Acids Suppress Ions for Amines Sanitation Depyrogenation Less Wear and Tear Higher Flow Fast Analysis More Robust Analysis Easier Method Development Stable Stationary Phases have advantages in terms of Selectivity, Column Lifetime, and Analysis Time

4 Improving the Stability of HPLC Phases: History Pure organic polymers Silica hardened by coating with alumina or zirconia Pure carbon Silica improvements Sterically bulk & bidentate ligand Polymer coated silica Hybrid organic-inorganic silicaceous composite phase Polymer coated porous alumina and zirconia Carbon coated zirconia Chemically bonded carbon-coated zirconia

5 ZirChrom Particle Properties ZirChrom -Carb particles are prepared by coating base zirconia particles with a thin layer of carbon using a chemical vapor deposition process Characteristic Property Surface Area (m 2 /g) 22 Pore Volume (cc/g) 0.3 Pore Diameter (Å) Porosity 0.45 Density (g/cc) 5.8 (2.5x silica) Particle Diameter (µ) 3.0 NH 2 Y + 2 HA + NaNO 2 = AN N Y + 2 H 2 O + NaA + N N + Y - C8 Bonding Reaction on Carbon Clad Zirconia Carbon Clad Zirconia Diazonium Salt Modified Carbon Clad Zirconia

6 DiamondBond : A New Family of Stable Phases O NH O NH O NH ZrO 2 DB-C8 ZrO 2 DB-C8 ZrO 2 DB-Amide8

7 DiamondBond-C8 Stability k' k' Butylbenzene (0.5M Nitric Acid) k' Butylbenzene (.0M NaOH) k' Butylbenzene (200 o C) Column Volumes LC Conditions: Base Stability DiamondBond Phase A, 30 x 4.6 mm id; Mobile phase, 50/50 ACN/Water; Flow rate,.0 ml/min.; Temperature, 30 o C; Injection volume, 5ul; Detection at 254nm. Acid Stability DiamondBond Phase A, 50 x 4.6 mm id; Mobile phase, 50/50 ACN/Water; Flow rate,.0 ml/min.; Temperature, 30 o C; Injection volume, 5ul; Detection at 254nm. Temperature Stability-- DiamondBond Phase B, 50 x 4.6 mm id; Mobile phase, 50/50 ACN/Water; Flow rate,.0 ml/min.; Temperature, 30 o C; Injection volume, 5ul; Detection at 254nm.

8 Test Chromatogram on DB-C8 2 Analytes 4 : Acetone 2: Benzonitrile 3: Ethylbenzene 4: Methylbenzoate DiamondBond-C8 3 >00000 plates/m ZirChrom-Carb LC Conditions: Column dimension, 50 x 4.6 mm id.; Mobile phase, 37.5/5/57.5 ACN/THF/Water; Temperature, 60 o C; Flow rate,.0 ml/min.; Injection volume, 5 µl; Detection at 254 nm.

9 22 Non-Ionizable Solutes Nonpolar Benzene Toluene Ethylbenzene p-xylene Propylbenzene Butylbenzene Cl Polar Br Cl O O Bromobenzene p-dichlorobenzene Anisole O O Methylbenzoate Napthalene Acetophenone O NO 2 CN NO 2 NO 2 Cl Benzonitrile Nitrobenzene p-nitrotoluene p-nitrobenzyl Chloride Benzophenone HB Donor Cl OH OH NH H OH OH O Benzylalcohol 3-Phenyl Propanol N-Benzyl Formamide Phenol p-chlorophenol Mobile phase, 40/60 Acetonitrile/Water; Flow rate,.0 ml/min.; Temperature, 30 o C; Detection at 254nm; 5 ul Injection volume.

10 Selectivity Comparison Diamondbond-C8 ODS- Unmodified Carbon coated zirconia

11 Effect of Polar Embedded Amide Absolute Retention on Silica RPAmide 00 0 p-chlorophenol Silica Amide vs. C8 Phenol 3-Phenylpropanol N-Benzylformamide Benzylalcohol Absolute Retention on Silica C8 Absolute Retention on Carbon RPAmide 00 0 Carbon Amide vs. C8 p-chlorophenol Phenol 3-Phenylpropanol N-Benzylformamide Benzylalcohol Absolute Retention on Carbon C8 RPAmide shows increased retention of HB Donors on silica and carbon-based phases

12 Why are Bonded Carbons Unique? Carbon p - electrons Bonded Carbon Carbon surfaces have π- electrons which increase retention of certain types of analytes: fused polyaromatics (e.g. naphthalene, etc) polar molecules (e.g. amides, ketones, alcohols, etc) Surface modified carbon surfaces combine some of these interactions with interactions specific to the bonded surface groups. Bonded Carbons maintain the high ph and thermal stability that is inherent in the C-C bond.

13 Shape Makes a Difference p-xylene ethylbenzene a ODS =.03 a CARB =.58 a DB-C8 =.22 C-C-C-C-C-C-C-C-C-C-C-C C-C-C-C-C-C-C-C-C-C-C-C

14 Shape Selectivity: Anabolic Steroids LC Conditions: Column, 50 x 4.6 DiamondBond-C8; Mobile phase, 60/40 ACN/Water; Flow rate, 2.0 ml/min.; Temperature, 00 o C; Injection volume, 0ul; Detection at 25nm; Solutes: =Epietiocholanolone, 2=Etiocholanolone, 3=Androsterone, 4=Epiandrosterone mau VWD A, Wavelength=25 nm (G:\HPCHEM\DATA\MDARCHIV\ D) Anabolic Steroids Separation in less than 3 minutes! min

15 High ph Stability - Beta Blockers Analytes - Atenolol 2 - Metoprolol 3 - Oxprenolol 4 - Alprenolol min LC Conditions: 20/20/60 ACN/THF/200 mm AH and 200 mm NaCl, ph 3.3 Flow Rate: ml/min. Temperature: 75 o C. Injection Volume: 5 ul Detection: 254 nm.

16 High Temperature Stability - Speed Resolution (min; 3,4) =2.2 Temperature = 2 o C Flow Rate =.4 ml/min. ACN/Buffer = 8.5/8.5 Analysis Time = 43 min. 6 min Resolution (min; 3,4) = 2.2 Temperature = 80 o C Flow Rate = 3.2 ml/min. ACN/Buffer = 8.8/9.2 Analysis Time = 2 min. Analytes: = Barbital 2 = Butabarbital 3 = Pentobarbital 4 = Carbromal 5 = Secobarbital 6 = Methohexital min Mobile Phase: ACN/5mM Ammonium phosphate, ph 7.0 Pressure drop =95 bar

17 Application in LC/MS/MS Intensity, cps XIC of +MRM (2 pairs): 35.2/93.2 amu THC in Saliva by LC/MS/MS Blue THC (tetrahydrocannabinol parent drug) Red D3 THC (Internal Standard) Column 50mm X 4.6mm DBC8 80 o ml/min Solvent A 20mM NH 4 CH 3 CO 2 in 70% Acetonitrile, 30% aqueous (0.% acetic acid, ph 4.5) Solvent B Acetonitrile Isocratic 35% A, 65%B 25 ul injection Time, min Data Courtesy R. Clouette - Clinical Reference Laboratories

18 Summary The effect of ligand type on retention for bonded carbon phases is similar to that for bonded silicas Unique surface chemistry enables unique separations The carbon-carbon attachment bond is extremely stable Low ph and High ph applications High Temperature / Fast HPLC Both normal and high ph, high temperature applications are possible on these new materials LC/MS pharmaceutical applications enabled by this technology