Flow Injection Preconcentration Coupled with Direct Sample Insertion for Inductively Coupled Plasma Atomic Emission Spectrometry

A flow injection (FI) preconcentration system has been coupled with a direct sample insertion (DSI) system for inductively coupled plasma atomic emission spectrometry (ICP-AES). The FI system provides a preconcentration factor of approximately 30. The DSI detection limit improvement, as compared to conventional nebulization detection limits, is element specific and ranges between 10 and 130 when a cup specifically designed for liquid work is used. The FI-DSI hybrid provides detection limit improvements ranging between 140 and 1200 for the elements tested—Cu, Pb, and Zn. Precision of the FI-DSI-ICP system averages 4% RSD for these three elements. FI processing time is 6.0 minutes with the use of 5-mL injection volumes. The system offers considerable potential for further improvement by increasing the injection volume and improving the interface to the DSI.