There are generally three primary factors that determine the overall ‘efficiency’ of an analysis undertaken by HPLC: Sample through-put, sensitivity and column performance. The increasing demand for chemical characterization has meant that the modern laboratory is faced with greater time-management challenges. Often more information is required from less, and high resolution requires high plate numbers.

HPLC-MS is widely used for chemical characterization. However, it is in this application of separation science where perhaps the greatest challenge exists in the optimization of these three factors, since there is significant conflict between obtaining high-speed, high performance and high sensitivity.

A serious limitation in HPLC-MS lies in the volumetric through-put of the detector. Practitioners of HPLC-MS commonly employ columns with 2 or 1 mm internal diameters, but at the sacrifice of column performance and sample loading. A new technology, referred to as Curtain Flow Technology has been developed which provides . higher N values, higher sample concentration presented to the detector and a reduced volumetric flow to the detector. Curtain flow columns with a diameter of 4.6 mm i.d. can be utilized and operated at high flow rates: solute can be transported directly to the MS without the need for post column splitting.

In this study, we show how curtain flow chromatography columns can be employed in the analysis of amino acids with improved performance compared to conventional columns. The advantages of curtain flow is that the analysis through-put can be increased by a factor of five, while at the same time there is a reduction in baseline noise, which results in an increase in the signal to noise response by up to 10-fold in comparison to standard columns with the same internal diameter and approaching 66-fold in comparison to standard columns with the same virtual internal diameter.