Agilent HPLC Column Selection Guide

Columns for Analytical HPLCColumn Stability Testing at pH 3 and 60°CColumn:ZORBAX SB-C8883975-9064.6 x 150 mm, 5 µm7.0Column: Eclipse XDB-C8993967-9064.6 x 150 mm, 5 µmMobile Phase: Purge Conditions:70% 50 mM NaAc-HCl, pH 3.030% ACNRetention Test Conditions:65% Methanol35% WaterFlow Rate: 1.0 mL/minTemperature: 60°CSample:Tricyclic AntidepressantsK of Amitriptyline6.56.05.55.00 2ZORBAX SB-C84 6 8 10 12Column Volumes of Mobile Phase (X1000)ZORBAX Eclipse XDB-C8Competitive C8LCEC005Eclipse XDB columns are stable over a wide pH range. At low pH, Eclipse, an end capped column is extremely stable and shows equivalent stability to a non-endcappedcolumn, SB-C8, at pH 3. The columns were purged with a pH 3 mobile phase at 60°C. Then they were tested with a strongly basic compound to determine if the endcappingor bonded phase had been hydrolyzed from the silica surface. The Eclipse XDB column was very stable, as shown by the consistency of the retention of amitriptyline overthe 12,000 column volumes of the test. Another endcapped column shows less stability under these same conditions.Selectivity Changes for Basic Compoundswith Eclipse XDB and StableBondColumn A:Eclipse XDB-C8966967-9064.6 x 75 mm, 3.5 µmColumn B: ZORBAX Rx/SB-C8866953-9064.6 x 75 mm, 3.5 µmMobile Phase: 70% 25 mM NaH 2 PO 4 , pH 3.030% MethanolFlow Rate: 1.0 mL/minTemperature: 35°CEclipse XDB and StableBond columns are basedon the same silica but have different bondingand endcapping. Therefore, they can have verydifferent selectivity for the same sample underthe same conditions, as this example shows.A32B1. Barbital2. Sulfamethoxazole3. Caffeine23110 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5Time (min)0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5Time (min)LCEC00834 Order online at www.agilent.com/chem/store