Normal Phase Chromatography operates on the principle of polarity differences between the stationary and mobile phases. In contrast to reversed phase HPLC, the stationary phase is polar (commonly unmodified or functionalized silica), while the mobile phase is nonpolar, typically composed of organic solvents such as hexane, isopropanol, or ethyl acetate.
This chromatographic mode is particularly effective for separating polar analytes, geometric and chiral isomers, and compounds with functional group variations. NP-Chromatography remains the method of choice for many synthetic chemists, natural product researchers, and chiral separations, offering reproducible results and predictable selectivity.
By fine-tuning the polarity of the mobile phase or introducing specific modifiers, retention and resolution can be precisely adjusted to suit the properties of the analytes.
Normal Phase Chromatography represents one of the oldest and most fundamental modes of High-Performance Liquid Chromatography (HPLC). It is especially suited for compounds that are poorly retained or unresolved under reversed phase conditions. With excellent selectivity for polar and structurally similar molecules, NPC continues to play an important role in method development, preparative purification, and chiral analysis.
The stationary phase in NP-Chromatography is polar, commonly consisting of bare silica gel or silica modified with functional groups such as amino (NH₂), cyano (CN), or diol. These surfaces interact with analyte molecules through hydrogen bonding, dipole–dipole interactions, and adsorption mechanisms. The surface chemistry and activity of the silica phase are key parameters influencing selectivity and reproducibility in normal phase separations.
Normal Phase Chromatography uses nonpolar organic solvents such as n-hexane, heptane, or dichloromethane, often combined with more polar modifiers like ethanol, isopropanol, or ethyl acetate. Adjusting the ratio of polar modifier controls analyte retention and resolution. Mobile phase dryness and water content play a crucial role, as trace moisture can significantly influence retention behavior and peak shape.
Retention in Normal Phase Chromatography is primarily driven by adsorption and polarity-based interactions between analytes and the stationary phase. More polar compounds are retained longer due to stronger interactions with the polar surface, while nonpolar molecules elute earlier. By varying solvent polarity or adding specific modifiers, chromatographers can fine-tune selectivity and optimize separation performance for complex mixtures.
| Name | Particle Sizes | Carbon Load | Pore Size |
|---|---|---|---|
| Adsorbosil CN | 5 – 10 µm | 5 % | 60 Å |
| Adsorbosil NH2 | 5 – 10 µm | 3 % | 60 Å |
| Adsorbosil Si | 5 – 10 µm | 0 % | 60 Å |
| Adsorbosphere CN | 3 – 10 µm | 6 % | 100 Å |
| Adsorbosphere NH2 | 3 – 10 µm | 6 % | 100 Å |
| Adsorbosphere PAC | 3 – 10 µm | 6 % | 100 Å |
| Adsorbosphere Si | 3 – 10 µm | 0 % | 100 Å |
| Adsorbosphere HS Si | 5 µm | 0 % | 100 Å |
| Adsorbosphere XL NH2 | 3 – 10 µm | 5 % | 100 Å |
| Adsorbosphere XL Si | 3 – 10 µm | 0 % | 100 Å |
| Allsphere Amino | 3 – 10 µm | 5.5 % | 80 Å |
| Allsphere Cyano | 3 – 10 µm | 7.5 % | 80 Å |
| Allsphere Silica | 3 – 10 µm | 0 % | 80 Å |
| Brava Amino | 3 – 10 µm | 4 % | 130 Å |
| Brava CN-BDS | 3 – 10 µm | 5 % | 145 Å |
| Brava Cyano | 3 – 10 µm | 5 % | 130 Å |
| Brava Silica | 3 – 10 µm | 0 % | 130 Å |
| CT-Sil CN | 5 µm | 7 % | 100 Å |
| CT-Sil Diol | 5 µm | 0 % | 100 Å |
| Econosil CN | 5 µm | 5 % | 60 Å |
| Econosil NH2 | 5 µm | 3 % | 60 Å |
| Econosil Silica | 5 – 10 µm | 0 % | 60 Å |
| Econosphere Amino | 3 – 10 µm | 3 % | 100 Å |
| Econosphere Cyano | 3 – 10 µm | 6 % | 100 Å |
| Econosphere Silica | 3 – 10 µm | 0 % | 100 Å |
| EcoPrep 60 Si | 10 µm | 0 % | 60 Å |
| EcoPrep 120 Si | 10 – 50 µm | 0 % | 120 Å |
| Equisil APS | 3 – 5 µm | 4 % | 120 Å |
| Equisil APS-2 | 5 µm | 4 % | 120 Å |
| Equisil CPS | 5 µm | 5 % | 120 Å |
| Equisil CPS-2 | 3 µm | 5 % | 120 Å |
| Equisil Si | 3 – 5 µm | 0 % | 120 Å |
| Equisil BDS CPS | 5 µm | 5 % | 130 Å |
| Equisorb CN | 3 – 10 µm | 7.5 % | 80 Å |
| Equisorb NH2 | 3 – 10 µm | 5.5 % | 80 Å |
| Equisorb Si | 3 – 10 µm | 0 % | 80 Å |
| Exsil 80 Amino | 3 – 10 µm | 80 Å | |
| Exsil 80 Nitrile | 3 – 10 µm | 80 Å | |
| Exsil 80 Nitrile EC | 5 µm | 80 Å | |
| Exsil 80 Nitrile HL | 3 – 5 µm | 80 Å | |
| Exsil 80 Si | 3 – 10 µm | 0 % | 80 Å |
| Exsil 100 Amino | 1.5 – 10 µm | 100 Å | |
| Exsil 100 Diol | 5 µm | 100 Å | |
| Exsil 100 HAAX | 5 µm | 100 Å | |
| Exsil 100 Hexyl | 5 – 12 µm | 100 Å | |
| Exsil 100 Nitrile | 1.5 – 10 µm | 100 Å | |
| Exsil 100 Nitrile HL | 5 µm | 100 Å | |
| Exsil 100 SH | 10 µm | 100 Å | |
| Exsil 100 Si | 1.5 – 10 µm | 0 % | 100 Å |
| Exsil Pure 120 Amino | 1.5 – 10 µm | 120 Å | |
| Exsil Pure 120 Nitrile | 1.5 – 10 µm | 120 Å | |
| Exsil Pure 120 Phenyl-Amino | 1.5 – 5 µm | 120 Å | |
| Exsil Pure 120 Si | 1.5 – 10 µm | 0 % | 120 Å |
| Exsil 300 PAX | 3 – 7 µm | 300 Å | |
| Exsil 300 Si | 3 – 10 µm | 0 % | 300 Å |
| Exsil Avanti CN (1) | 3 – 5 µm | 130 Å | |
| Exsil Avanti NH2 (2) | 3 – 5 µm | 130 Å | |
| Exsil Avanti Si | 1.5 – 10 µm | 0 % | 130 Å |
| Exsil Avanti BDS CN | 3 – 5 µm | 145 Å | |
| Exsil Avanti BDS Si | 3 – 10 µm | 0 % | 145 Å |
| Exsil Clasico CN | 3 – 10 µm | 90 Å | |
| Exsil Clasico NH2 | 8 µm | 90 Å | |
| Exsil Clasico Si | 5 – 8 µm | 90 Å | |
| Exsil NP Si | 1 – 50 µm | 0 % | 0 Å |
| Gold-Turbo 100 Si | 1.5 µm | 100 Å | |
| GreatSmart NH2 | 3 – 10 µm | 5 % | 120 Å |
| GreatSmart Silica | 3 – 10 µm | 0 % | 120 Å |
| Grom Sapphire 65 Si | 5 µm | 65 Å | |
| Grom Sapphire 110 Si | 5 µm | 110 Å | |
| GromSil Amino-3 CP | 5 µm | 100 Å | |
| GromSil 60 Diol | 5 µm | 60 Å | |
| GromSil 60 NP-2 | 3 – 5 µm | 60 Å | |
| GromSil 80 Amino-1 PR | 3 – 10 µm | 80 Å | |
| GromSil 80 Cyan-2 PR | 3 – 5 µm | 80 Å | |
| GromSil 80 NP-1 | 3 – 5 µm | 80 Å | |
| GromSil 100 Amino-1 PR | 5 – 10 µm | 100 Å | |
| GromSil 100 NP-1 | 3 – 10 µm | 100 Å | |
| GromSil 100 NP-4 | 5 µm | 100 Å | |
| GromSil 120 Cyan-1 ST | 3 – 10 µm | 120 Å | |
| GromSil 120 Diol | 3 – 10 µm | 120 Å | |
| GromSil 120 NP-2 | 3 – 20 µm | 120 Å | |
| GromSil 120 SEC | 3 – 5 µm | 120 Å | |
| GromSil 200 Diol | 5 µm | 200 Å | |
| GromSil 200 SEC | 5 µm | 200 Å | |
| GromSil 300 Amino-4 PR | 3 – 7 µm | 300 Å | |
| GromSil 300 Cyan-1 ST | 3 – 10 µm | 300 Å | |
| GromSil 300 Diol | 3 – 5 µm | 300 Å | |
| GromSil 300 NP-1 | 5 µm | 300 Å | |
| GromSil 300 SEC | 5 µm | 300 Å | |
| Spherigrom CN | 5 µm | 80 Å | |
| ReproSil Mixed-Mode Amino-C8 | 3 – 5 µm | 11 % | 100 Å |
| ReproSil Mixed-Mode Amino-C18 | 3 – 5 µm | 17 % | 100 Å |
| ReproSil Mixed-Mode Cyano-C18 | 5 µm | 12 % | 100 Å |
| Platinum Amino | 3 – 10 µm | 100 Å | |
| Platinum Cyano | 3 – 10 µm | 100 Å | |
| Platinum Si | 3 – 10 µm | 0 % | 100 Å |
| Platinum 300 CN | 5 µm | 300 Å | |
| Platinum 300 Si | 3 – 15 µm | 0 % | 300 Å |
| Reprobond CN | 10 µm | 7 % | 120 Å |
| Reprobond NH2 | 10 µm | 4 % | 120 Å |
| Reprobond Si | 10 – 45 µm | 0 % | 120 Å |
| ReproKrom Si | 5 – 10 µm | 0 % | 100 Å |
| ReproShell Si | 2.7 – 5 µm | 0 % | 90 Å |
| ReproSil-Si, Saturator column | N/A | ||
| ReproSil 70 CN | 5 µm | 10 % | 70 Å |
| ReproSil 70 Diol | 5 µm | 4 % | 70 Å |
| ReproSil 70 NH2 | 5 µm | 5 % | 70 Å |
| ReproSil 70 Si | 5 – 50 µm | 0 % | 70 Å |
| ReproSil 80 CN | 3 – 10 µm | 3.5 % | 80 Å |
| ReproSil 80 Diol | 5 µm | 0 % | 80 Å |
| ReproSil 80 NH2 | 3 – 5 µm | 2 % | 80 Å |
| ReproSil 80 Si | 3 – 5 µm | 0 % | 80 Å |
| ReproSil 100 CN | 3 – 10 µm | 2 % | 100 Å |
| ReproSil 100 Diol | 5 – 10 µm | 3 % | 100 Å |
| ReproSil 100 DNH | 5 – 50 µm | 5 % | 100 Å |
| ReproSil 100 NH2 | 3 – 10 µm | 3 % | 100 Å |
| ReproSil 100 Polyamin-2 | 3 – 5 µm | 8 % | 100 Å |
| ReproSil 100 Si | 3 – 20 µm | 0 % | 100 Å |
| ReproSil Amid-C12 | 1.5 – 10 µm | 9 % | 120 Å |
| ReproSil Amid-C16 | 5 µm | 100 Å | |
| ReproSil Amid-C18 | 3 – 10 µm | 100 Å | |
| ReproSil Amid-C18 ABZ | 3 – 5 µm | 12.5 % | 200 Å |
| ReproSil Amid-C18-e | 5 µm | 100 Å | |
| ReproSil 150 CN | 3 – 5 µm | 5 % | 150 Å |
| ReproSil 150 Si | 5 µm | 0 % | 150 Å |
| ReproSil 200 Diol | 5 µm | 200 Å | |
| ReproSil 200 Si | 5 µm | 0 % | 200 Å |
| ReproSil 300 DEAE | 5 µm | 300 Å | |
| ReproSil 300 Polyamin | 3 – 7 µm | 300 Å | |
| ReproSil-Pur 60 Si | 3 – 5 µm | 0 % | 60 Å |
| ReproSil-Pur 120 CN | 3 – 10 µm | 7 % | 120 Å |
| ReproSil-Pur 120 Diol | 3 – 10 µm | 7 % | 120 Å |
| ReproSil-Pur 120 NH2 | 3 – 10 µm | 4 % | 120 Å |
| ReproSil-Pur 120 Si | 1.9 – 10 µm | 0 % | 120 Å |
| ReproSil-Pur 200 Diol | 1.9 – 5 µm | 5 % | 200 Å |
| ReproSil-Pur 200 Si | 3 – 5 µm | 0 % | 200 Å |
| ReproSil-Pur 300 CN | 3 µm | 300 Å | |
| ReproSil-Pur 300 Diol | 3 – 5 µm | 3.5 % | 300 Å |
| ReproSil-Pur 300 Si | 3 – 10 µm | 0 % | 300 Å |
| ReproSil-Pur 1000 NH2 | 3 – 5 µm | 1 % | 1 000 Å |
| ReproSil-Pur 1000 Si | 5 µm | 0 % | 1 000 Å |
| ReproSil-Pur Basic 100 Si | 3 – 5 µm | 0 % | 100 Å |
| ReproSil Saphir 100 NH2 | 5 µm | 4 % | 100 Å |
| ReproSil Star NH2 | 5 µm | 3.5 % | 120 Å |
| ReproSil Star Si | 5 µm | 120 Å | |
| ReproSil Star ZIK HILIC | 1.5 – 5 µm | 5 % | 120 Å |
| ReproSil-XR 120 CN | 3 – 5 µm | 5 % | 120 Å |
| ReproSil-XR 120 NH2 | 3 – 10 µm | 5 % | 120 Å |
| ReproSil-XR 120 NH2-e | 5 µm | 5 % | 120 Å |
| ReproSil-XR 120 Si | 3 – 10 µm | 0 % | 120 Å |
| Reprospher 100 CN | 1.8 – 10 µm | 7 % | 100 Å |
| Reprospher 100 CN-DE | 1.7 – 10 µm | 7 % | 100 Å |
| Reprospher 100 Diol | 3 – 10 µm | 7 % | 100 Å |
| Reprospher 100 Diol-DE | 5 µm | 7 % | 100 Å |
| Reprospher 100 DNH | 3 – 10 µm | 5 % | 100 Å |
| Reprospher 100 NH2 | 3 – 5 µm | 4 % | 100 Å |
| Reprospher 100 NH2-DE | 1.8 – 5 µm | 4 % | 100 Å |
| Reprospher 100 PEI | 3 – 50 µm | 13 % | 100 Å |
| Reprospher 100 Si | 1.7 – 10 µm | 0 % | 100 Å |
| Reprospher Carbohydrate | 5 µm | 4.5 % | 100 Å |
| Reprospher 200 Si | 5 µm | 0 % | 200 Å |
| Reprospher 300 PEI | 3 – 10 µm | 4 % | 300 Å |
| Stability ABZ-Amid-C18 | 3 – 5 µm | ||
| Stability Polyamin | 3 – 5 µm | 300 Å | |
| Stability 100 Amid-C16 | 3 – 5 µm | 100 Å | |
| Stability 100 Amid-C18 | 3 – 5 µm | 100 Å | |
| Stability 100 Amid-C25 | 5 µm | 100 Å | |
| Stability 100 Polyamin-2 | 3 – 10 µm | 100 Å | |
| Stability 120 Amid-C12 | 1.5 – 5 µm | 120 Å | |
| Stability 300 Polyamin-2 | 3 – 10 µm | 300 Å | |
| Techsphere NH2 | 3 – 5 µm | 100 Å | |
| Ultrasep 100 NH2-DE | 5 µm | 100 Å | |
| Ultrasep ES 100 CN | 5 µm | 100 Å | |
| Ultrasep ES 100 NH2 | 5 µm | 100 Å | |
| Ultrasep ES 100 OH | 5 µm | 100 Å | |
| Ultrasep ES 100 Si | 5 µm | 100 Å | |
| VisionHT HILIC | 1.5 – 10 µm | 120 Å | |
| VisionHT Silica | 1.5 – 10 µm | 120 Å |