Electron-capture detection in reversed-phase liquid chromatography using packed-capillary columns

✍ Scribed by Bart N. Zegers; Jody F.C. de Brouwer; Aldi Poppema; Henk Lingeman; Udo A.Th. Brinkman

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 788 KB
• Volume: 304
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(94)00552-w

✦ Synopsis

A new type of interface has been developed for the direct coupling of packed-capillary reversed-phase liquid chromatography with electron-capture detection. This interface allows the detection of relatively non-volatile and/or polar compounds, and simply consists of a fused-silica capillary (50 pm I.D.) inside of a stainless-steel capillary (0.32 mm I.D.) connecting the analytical column with the detector through the oven wall. The make-up gas is used for cooling of the fused-silica capillary. With flow-injection analysis the influence of several parameters (e.g. flow-rate of the make-up gas and mobile phase, oven temperature) on the performance of the total system (i.e. band broadening, sensitivity) has been studied. Using optimal conditions (flow-rate 2 ~1 min-', make-up gas 40 ml N, min-', oven temperature 300" C, injection volume 60 nl) separation and detection of mononitroanilines, chlorophenols, pesticides and benzodiazepines have been performed. Detection limits are in the range of lo-450 pg (0.2-7 mg 1-r) under reversed-phase conditions. Large-volume injections up to 15 ~1, using a non-eluting solvent (water) to focus the analytes on top of the column, have been performed to increase the sensitivity of the system. This technique increased the concentration sensitivity with 2-3 orders of magnitude allowing the detection of ca. 150 ng I-' of chlorophenols in river Meuse water.