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WelchromTM AQ-C18
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- Moderate surface coverage and fully end-capped
- Excellent peak shape for acids, bases and neutrals
- Compatible in 100% aqueous mobile phase condition, very unique for a universal C18 column
- Extended retention in highly aqueous mobile phase condition for highly polar compounds such as organic acids, peptides, nucleotides bases and water soluble vitamins
- Slightly different selectivity from C18
- Longer lifetime in aqueous eluents
- Exceptional batch-to-batch and column-to-column reproducibility
- Available in dimensions from analytical to preparative for all sample sizes
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| WelchromTM AQ-C18 columns are designed to show extended retention and selectivity for hydrophilic and polar compounds, which are either not or poorly retained on other phases. A proprietary bonding chemistry prevents so-called ＾phase collapse￣, which conventional C18 columns exhibit at high water contents in the mobile phase, even when 100% water is used. The AQ-C18 phase is fully end-capped to ensure the best peak shapes for polar and basic compounds and longer lifetime. Typical applications are separations of biomolecules, metabolites, and pharmaceutical degradants such as organic acids, water-soluble vitamins, oligosaccharides, amino acids, and small peptides and nucleotides. The AQ-C18 phase provides stable base line, high sensitivity and long retention even under neutral pH conditions, or without either buffer or counter-ion additives. These properties make this phase especially suitable for LC/MS. |
| WelchromTM AQ-C18 phase shows similar selectivity as conventional C18 phases when used for separations of hydrophobic compounds with typical reversed phase mobile phases, thus suitable as a unique universal C18 column. |
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No Phase Collapse |
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| For very polar analytes, because of solubility reasons, a highly aqueous mobile phase with a minimal concentration of organic modifier, sometimes less than 5%, has to be used in order to retain analytes on the column. Under such conditions, conventional C18 columns exhibit loss of retention time over time, or sudden loss of retention time when the pump is stopped, a phenomenon commonly known as ＾phase collapse￣. WelchromTM AQ-C18 columns are moderately bonded with extensive endcapping to prevent ＾phase collapse￣ under highly aqueous mobile phase. The following graphs show chromatograms of AQ-C18 column¨s initial performance and performance after flushing in 100% aqueous mobile phase for 200 hours. There is almost no retention drop over 200 hrs¨ of usage. |
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Increased Retention for Polar Compounds |
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| Polar compounds can be difficult to retain on conventional C18 column as they tend to elute at or very close to the void volume. WelchromTM AQ-C18 phase provides additional analyte-ligand interaction and shows increased retention of polar compounds, especially for earlier eluting peaks. Compared with WelchromTM XB-C18 phase, AQ-C18 is less hydrophobic. WelchromTM AQ-C18 phase has less retention for the neutral compounds and longer retention for the highly polar compounds, providing an alternative selectivity as compared to XB-C18 phase. The following shows the comparison of WelchromTM XB-C18 and AQ-C18 on earlier eluting peaks. |
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Applications |
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| Typical applications of WelchromTM AQ-C18 are LC and LC/MS separations of biomolecules, metabolites, pharmaceutical degradants such as organic acids, water-soluble vitamins, oligosaccharides, amino acids, small peptides and nucleotides, and traditional Chinese medicines. The following chromatograms show separation of water-soluble vitamins, organic acids, and basic nucleotides and purines. |
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Performance Comparison |
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The above graph shows the comparison of WelchromTM AQ-C18 with other AQ-C18 columns on separation of 6 highly polar strong organic acids. WelchromTM AQ-C18 shows the longest retention, better peak shapes, and best resolution among the other three AQ-C18 columns. |
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Recommended Substitute For |
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Aquasil
C18 |
Atlantis™ |
Synergi
Hydro-RP |
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HydroBond PS C18 |
Ultra
Aqueous C18 |
ProntoSIL C18 AQ |
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Zorbax®
SB-Aq |
YMC-Pack
ODS-AQ |
HydroBond AQ |
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