The term polymer additives covers a wide variety of chemistries, and this experiment concentrates on two commonly used groups: polar and non-polar. A legacy polymer additive method is optimized using the column calculator to accommodate a change in column chemistry with scalability and wide chemical compatibility for this analysis (Figure 2).³ The first experiment is separating the known co-eluting Tinuvin 327 and 328 using the THF-compatible APC System with a p-QSM elution gradient pump (Figure 3). The second experiment is separating a mixture containing non-polar Irganox samples 1330, 1010, and 1076 and the comparatively polar Tinuvin samples 328, 327, and 360 (Figure 4).
Transferring a legacy polymer additive separation method to a new column is easily done using a column calculator tool. For the analysis of polymer additives, the legacy method is transferred to the APC System with p-QSM for gradient elution using aggressive solvents, like THF. When entering the column choices, the ratio of column length to packing particle size (L/dp) is kept constant between methods. According to United States Pharmacopeia (USP) guidelines, using a constant L/dp allows the new method to be used without revalidation.⁴ The column calculator tool enables planning of the experiment, ordering columns, and consideration of system capabilities before entering the lab. Instrument capabilities, such as system pressures and solvent consumption, have an impact on safely performing analytical procedures.
