YMC Analytical Columns: Pro Family : YMC Hydrosphere C18 |
- stable under the use of 100% aqueous eluent
- UltraHT Hydrosphere for Fast-LC (2μm particle size)
- “hydrophilic” C18 surface for enhanced polar recognition
- no need for ion pair reagents
- based on highly inert, ultrapure, pH neutral silica specifically designed for pharmaceutical and biotechnology R&D
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Click here to view the full list of Hydrosphere parts
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Specification |
Particle size / µm |
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Pore size / nm |
12 |
Surface area / m2g-1 |
340 |
Carbon content / % |
12 |
Recommended pH range |
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| *UltraHT for Fast-LC |
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General
The separation of polar compounds in many cases requires highly aqueous mobile phase conditions to achieve sufficient retention on the stationary phase. Conventional reversed phase selectivities do not give reproducible results under these conditions due mainly to the collapse of the C18 chains, Hydrosphere C18 has been developed, on the ultra pure silica support of the ProFamily, as the next generation of speciality phases following the well known YMC-Pack ODS-AQ, which was developed in 1987 and is still a very interesting selectivity option for these purposes.
In order to compare the differences and similarities of both reversed phases, nucleic acid bases are separated under pure aqueous eluent conditions on both selectivities. Interestingly uracil, normally used as a dead volume marker, can be retained on both phases, whereas adenine elutes later on YMCPack ODS-AQ. This peak on Hydrosphere C18 is virtually symmetrical with a tailing factor of 1.05, but on YMC-Pack ODS-AQ it shows a slightly tailing peak (with a tailing factor of 1.49).
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| Hydrosphere C18 vs. YMC-Pack ODS-AQ* |
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Column: 150 x 4.6 mm
Eluent: 20mM KH2PO4-K2HPO4 (pH 6.9)
Flow rate: 1.0 ml/mins
Temperature: 37° C
Detection: UV at 254 nm |
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As a consequence, both Hydrosphere C18 and YMC-Pack ODS-AQ are the selectivities of choice within the YMC portfolio to separate polar compounds when using 100% aqueous eluent conditions. YMC-Pack ODS-AQ shows stronger retention for more hydrophobic substances, while Hydrosphere C18 is ideal for basic substances.
Both selectivities are a “must” for approaching the separation of polar compounds. |
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Properties
A proprietary derivatisation procedure enables Hydrosphere C18 to be penetrated by water without losing its brush-like chain structure. This model of the so-called phase collapse is one explanation for a phenomenon, where the retention times decrease after a very short time under 100% aqueous eluent on a conventional C18 phase.
Here, the retention behaviour of a conventional ODS column and Hydrosphere C18 under 100% aqueous conditions is compared. Its “hydrophilic” C18 surface gives Hydrosphere C18 the capability to show stable retention times even after 24 hours under these chromatographic conditions. |
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| Problem: Conventional ODS under 100% aqueous chromatographic conditions* |
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Column: 150 x 4.6 mm i.d.
Eluent: 20 mM KH2PO4-K2HPO2 (pH 6.9)
Flow rate: 1.0 ml/min
Temperature: 37 °C
Detection: UV at 254 nm |
After use, the column was stored overnight without any washing procedure. The next day, the application was continued. |
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| Solution: Hydrosphere C18 under 100% aqueous chromatographic conditions* |
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Column: 150 x 4.6 mm i.d.
Eluent: 20 mM KH2PO4-K2HPO2 (pH 6.9)
Flow rate: 1.0 ml/min
Temperature: 37 °C
Detection: UV at 254 nm |
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After use, the column was stored overnight without any washing procedure. The next day, the application was continued. |
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*By courtesy of YMC Co., Ltd. |
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Column care
Hydrosphere C18 is stable towards hydrolysis between pH 2 - 8 in up to 100% aqueous systems and a maximum of 50 °C. Remove acid and buffer salts before storage. Store the column in methanol / water = 70/30.
For detailed information please refer to the “Column Care and Use Instructions” which are shipped with each analytical column.
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