Tuning a Parallel Segmented Flow Column and Enabling Multiplexed Detection

Abstract

Active flow technology (AFT) is new form of column technology that was designed to overcome flow heterogeneity to increase separation performance in terms of efficiency and sensitivity and to enable multiplexed detection. This form of AFT uses a parallel segmented flow (PSF) column. A PSF column outlet end-fitting consists of 2 or 4 ports, which can be multiplexed to connect up to 4 detectors. The PSF column not only allows a platform for multiplexed detection but also the combination of both destructive and non-destructive detectors, without additional dead volume tubing, simultaneously. The amount of flow through each port can also be adjusted through pressure management to suit the requirements of a specific detector(s). To achieve multiplexed detection using a PSF column there are a number of parameters which can be controlled to ensure optimal separation performance and quality of results; that is tube dimensions for each port, choice of port for each type of detector and flow adjustment. This protocol is intended to show how to use and tune a PSF column functioning in a multiplexed mode of detection.

(−)-Epicatechin—An Important Contributor to the Antioxidant Activity of Japanese Knotweed Rhizome Bark Extract as Determined by Antioxidant Activity-Guided Fractionation

“…Among the free radical-scavenging methods, the DPPH assay is the fastest, the most straightforward, relatively inexpensive, efficient, and, therefore, the most frequently employed. Many studies on DPPH assay-guided fractionation of various plant materials have already been performed [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ], including on-line methods with pre-column [ 27 ] or post-column [ 28 , 29 , 30 , 31 , 32 , 33 , 41 ] DPPH reactions. On-line methods for measurement of the free radical-scavenging activity indicate the antioxidant fractions/compounds in a fast and inexpensive way, without the need to isolate and test them off-line , which is time consuming, as described in [ 28 ].…”