Application of different stationary phases having different modes of retention can be very effective and powerful, whether you’re starting out with a new method development project or whether you’re trying to “tweak” a method you’ve already developed.

Among the newer ACE Excel phases are several that can be used with very low or no organic modifier for polar analytes. Three of these newer phases are highlighted in a current promotion entitled, “The Polar Power of 3”, namely the ACE Excel C18-PFP, C18-Amide and the CN-ES. The analyte-stationary phase interactions for each phase are summarized below:

C18-PFP:       hydrophobic, π–π, dipole-dipole, hydrogen bonding, and shape-selective interactions

C18-Amide:   hydrophobic and hydrogen bonding interactions

CN-ES:          hydrophobic and dipole-dipole interactions

The following short video discusses these three phases in additional detail, and describes how you can take advantage of this popular offer.

Click here to watch the video.

Figure 1 Example showing different selectivities of C18-PFP, C18-Amide and CN-ES from a screening experiment
for a sample containing acidic, basic and neutral analytes

Chromatograms show results of a screening experiment using 2.1 x 50 mm, 2 µm ACE Excel columns obtained with 8-min gradients from 4 to 80% acetonitrile/ammonium acetate (pH 4.75) at 0.5 mL/min and 35°C. Significant differences in elution order are observed with each phase. Comparable, but different, changes in relative retention were observed among the three phases using methanol as organic modifier.

Short, efficient columns allow you to quickly determine which combination(s) of phase, organic modifier and pH can be selected for further optimization using temperature, gradient steepness, and even organic modifier ratio (CH3CN/CH3OH).


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