Performance Assessment of the Waters Breeze QS HPLC System GPC Applications

This application brief assess the performance of Waters Breeze QS HPLC System for Gel Permeation Chromatography (GPC).

Benefits

• Waters Breeze QS HPLC System, running Empower QuickStart Software, delivers precise flow rate to obtain accurate, reproducible peaks in GPC tests.
• Waters most affordable GPC analysis using a Breeze QS HPLC System.
  
• Empower QuickStart (QS) Software: a simplified and intuitive workflow.
  
• Linear GPC separation to 7 million Daltons with a Waters Ultrahydrogel Linear Column.

Gel permeation chromatography (GPC) requires a high performance liquid chromatography (HPLC) system that delivers precise flow and reproducible results. In GPC, the retention time is plotted against the log of the molecular weight. Thus, flow rate variations can affect peak reproducibility. The flow rate for this experiment is listed in the method parameters (Table 1). The molecular weight of experimental samples is calculated by comparing of unknown  sample data to a calibration curve using narrow molecular weight polyethylene oxide (PEO) and polyethylene glycol (PEG) calibration standards (Figure 1).  

The excellent flow rate precision of Breeze isocratic pumps is demonstrated in an overlay of six injections of a PEO/PEG mixed molecular weight standard, as shown in Figure 2. Relative standard deviations of the peak molecular weight (Mp) at <0.5% are obtained on a Waters Breeze QS HPLC System using two linear GPC columns and a 30-minute run time (Table 2).

Empower QS Software provides easy-to-use fundamental GPC calculations. In this experiment, the narrow PEO/PEG standards are used as calibration standards, as well as broad unknowns. The Empower QS Software’s partial list of reportable peak result fields includes Mn, Mw, Mp, Mv, Mz, Mz+1, and polydispersity (Figure 3). Relative and modified universal calibration types employing point-to-point and first- through fifth-order fits are available, and an example of relative calibration is shown in Figure 1.

Empower QS has many built-in features that enable sophisticated reporting of data usually done in spreadsheets. Two popular reporting areas are column plate counts and control charting. By reporting the column plate counts, the column efficiency can be charted and observed for any changes in performance (Table 3). Control charts can capture upper and lower limits of molecular weight ranges used in a polymer pre-manufacture notice (PMN) or for charting impurity levels in raw materials (Figure 4).

• Breeze isocratic pumps provide the excellent flow precision necessary for high-quality gel permeation chromatography.
  
• All basic GPC calculations can be calculated using the easy-to-use interface included with Empower QS Software.
• Short analysis time of 30 minutes was demonstrated using two linear columns.

1. Waters Corporation. Gel Permeation Chromatography (GPC) Capabilities. https://www.waters.com/waters/ library.htm?cid=511436&lid=134697666, August 2014.
   
2. Waters Corporation. Empower GPC Software Getting Started Guide. https://www.waters.com/waters/ support.htm?lid=1852970, May 2004.
3. Waters Corporation. Empower Tips. https://blog.waters.com/category/empower-tips