Allureâ¢ Acidix HPLC Column - Chromtech.com.au

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Restek -- Ultra IBD Intrinsically Base Deactivated HPLC Column as do most C18 chains under high aqueous mobile phase conditions (see Figure 1). Chain folding on C18 phases results in complete or partial loss of retention and resolution. Fourth, the Ultra IBD phase shows excellent peak shape for acids, bases, and zwitterions. The polar group plays an active role in deactivating undesirable silanol interactions with the analyte. As a result, samples containing mixtures of widely different pKa's can be run simultaneously. Finally, the Ultra IBD phase is often a good choice for LC-MS applications. Simple, MS-compatible mobile phases can be used with IBD columns while maintaining good peak shape and selectivity. IBD columns are an excellent alternative to ion pair methods on conventional C18 phases. II. Applications Figure 1A depicts the chain collapsing phenomenon associated with most C18 and some C8 phases under high aqueous mobile phase conditions. With insufficient organic content in the mobile phase, the hydrophobic chains of the phase fold down on themselves to obtain an energetically more favorable position, to avoid the outer aqueous, hydrophilic environment. The chains are no longer in a position to interact with the analytes, resulting in partial or complete loss of retention, depending on the degree of chain folding. In contrast, under the same high aqueous mobile phase conditions, the Ultra IBD phase provides essentially no net gain in energy from chain folding, because the polar group within the chain is hydrophilic. Therefore, the chains remain extended and can continue to interact with the analytes (Figure 1B). Typically, this scenario is chromatographically manifested in reversed-phase mode as plotted in Figure 1C, where retention continues on an upward swing (no loss of retention) even at 100% aqueous mobile phase composition. Peak shape of basic compounds on silica bonded phases can be improved by lowering the pH to protonate active silanols. However, there are times when more neutral conditions are required, such as with samples that are labile at acidic pH's. The Ultra IBD phase performs well even at neutral pH (see Figure 2), which makes it a particularly valuable packing in this instance. Figures 3 and 4 serve as examples of how the Ultra IBD phase performs well for acid/base mixtures. Many C18 packings show good peak shape for acids (in the case of active phases) or bases (in the case of deactivated phases), but not for both. The Ultra IBD phase exhibits good peak shape for a wide variety of solute types, at both acidic (Figure 3) and neutral (Figure 4) pH. It is noteworthy that the Ultra IBD phase is similar to conventional C18 phases in one aspect. That is, acidic mobile phases decrease retention for basic analytes and increase retention for acidic analytes. To increase retention for bases and/or increase retention for acids, use a neutral pH mobile phase. Retention of polar compounds that are difficult to obtain on C18 phases can often be retained on the Ultra IBD phase. The famotidine/ranitidine chromatogram in Figure 5 is indicative of this increased retention of polar compounds. III. Summary Ultra IBD columns are intrinsically base deactivated phases for reversed-phase separations of acids, bases, zwitterions and polar compounds. They demonstrate strength in areas weakly serviced by http://www.restekcorp.com/pinn_ibd.htm (2 of 3) [12/7/01 8:56:21 PM]
Restek -- Ultra IBD Intrinsically Base Deactivated HPLC Column traditional C18 columns, including retention of polar solutes, good peak shape for compounds containing a wide variety of pKa's, and the ability to use high aqueous mobile phases in separations. Employment of Ultra IBD columns in place of conventional C18 phases often eliminates the need for ion pair reagents in the mobile phase. This is especially important for LC/MS work. Generally, they also are more selective than C18 phases. IV. Product Listing Ultra IBD Columns, 5µm, 100Å Cat # Description 91755 Bulk Silica 9175532 30 x 2mm 9175552 50 x 2mm 9175512 100 x 2mm 9175562 150 x 2mm 9175522 200 x 2mm 9175572 250 x 2mm 9175533 9175553 9175513 9175563 9175523 9175573 9175535 9175555 9175515 9175565 9175525 9175575 917550212 917550210 917550220 30 x 3mm 50 x 3mm 100 x 3mm 150 x 3mm 200 x 3mm 250 x 3mm 30 x 4.6mm 50 x 4.6mm 100 x 4.6mm 150 x 4.6mm 200 x 4.6mm 250 x 4.6mm 10 x 2mm (3-pk.) 10 x 4mm (3-pk.) 20 x 4mm (2-pk.)
Page 1 and 2: Restek Advantage, Summer 1999: Allu
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Page 5 and 6: Restek -- LC/MS Columns Restek HPLC
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Page 11 and 12: Restek -- LC/MS Columns
Page 13 and 14: RAS[TM] -- Allure[TM] Basix HPLC Co
Page 21 and 22: Restek Advantage, Fall 2000: Ultra
Page 23 and 24: Restek Advantage, Fall 2000: Ultra
Page 25 and 26: Restek -- HPLC Methods Development
Page 27 and 28: Restek -- HPLC Applications (PDF) H
Page 29 and 30: Restek -- HPLC Applications (PDF) C
Page 31 and 32: Ascorbic Acid on Allure Acidix (LC
Page 33 and 34: Adenine Nucleotides on Allure Acid
Page 35 and 36: Acetaminophen on Allure Acidix Pea
Page 37 and 38: Ibuprofen and Naproxin on Allure A
Page 39 and 40: Tricyclic Antidepressants on Allure
Page 41 and 42: Ibuprofen and 1 Application Note:00
Page 43 and 44: Timolol Maleate on Allure Basix Pe
Page 45 and 46: Metoprolol on Allure Basix Peak Li
Page 47 and 48: Cyclobenzaprine on Allure Basix Pe
Page 49 and 50: Norethindrone and 1 Application Not
Page 51 and 52: Sertraline HCI on Allure Basix Pea
Page 53 and 54: Verapamil HCL on Allure Basix Peak
Page 55 and 56: Atenolol on Allure Basix Peak List
Page 57 and 58: Trycyclic Antidepressants Applicati
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Norgestrel and Application Note: LC
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Norgestrel and Ethynyl Estradiol on
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EPA Method 8330 Application Note:00
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Benzaldehyde, Hydrocortisone, and P
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Carbamates on Ultra IBD Peak List:
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Thymine, Thymidine, TTP, TDP, and T
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Cytosine, Cytidine, CTP, CDP, and C
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11 Component Mixture of Nucleotides
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LC/MS of Cephradine on Ultra IBD Ap
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Cephaloridine by Normal Phase on Ul
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Cephalexin and Cephradine on Ultra
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Digoxin on Ultra IBD Peak List: 1.
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Furosemide on Ultra IBD Peak List:
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Acids and Bases @ pH3 Application N
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Levothyroxine on Ultra PFP Peak Lis
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EPA 8330 on Ultra Cyano Peak List:
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Calcium Channel Blockers Applicatio
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Organic Acids on Application Note:
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Carbonyls Application Note:0036 1 2
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Beclomethasone and des-chlorobeclom
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β-Estradiol, Norethindrone and Eth
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Restek Corporation -- Product Infor
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