Narrow bore post column derivatisation assays via reaction flow chromatography

Abstract

This study highlights the capability to conduct a post column derivatisation (PCD) process with a narrow bore, low volume column. A reaction flow (RF) HPLC column (30 mm × 2.1 mm internal diameter (i.d.), 3 μm particle diameter) enabled the selective detection of phenols for both a simple standard mixture and a complex sample represented by green tea. The resolving power and sensitivity obtained were similar to an analytical scale (4.6 mm i.d.) RF HPLC column of the same format. However, the baseline noise experienced was higher when the assay was scaled down from the RF 4.6 mm i.d. to the RF 2.1 mm i.d. narrow bore column. The PCD mixing and reaction speed inside the RF column outlet (frit and head-fitting design) enabled the coupling of PCD protocols with “UHPLC-type” low volume columns and systems without significant loss in separation performance. In comparison to a conventional analytical scale PCD approach the scaled down narrow bore RF approach demonstrated 40 times greater sensitivity in terms of S/N. Scaled down PCD is vital for decreased consumption and cost without significant loss in separation performance.