Chapter 17 - Flow-Cell Analysis

Abstract

The chapter begins with a description of flow-cell detectors used for the measurement of radionuclides or radioisotope-labeled compounds separated in high-performance liquid chromatography (HPLC) effluent streams including liquid (homogeneous) flow cells, solid (heterogeneous) flow cells, gamma and PET flow cells, and narrow-bore and micro-bore flow cells. The principles of flow scintillation analysis (FSA) are discussed including the determination of count rates, background and net count rates, counting efficiency and disintegration rates, minimal detectable activity, sensitivity, resolution, precision, detection optimization, and instrument performance assessment. Dual-functionality flow-cell detectors, which selectively concentrate and detect radionuclides, are described. Among these are flow-cell detectors consisting of scintillating extractive resins, composite beds of scintillating and extracting particles, equilibrium-based detection, fountain-flow planar detectors, whole column detectors, and planar detectors based on semiconductor diodes. The chapter also describes flow-cell analysis of radionuclides sequential to their separation including applications in nuclear waste and process monitoring, measurements of actinides and 90 Sr in soil, alpha/beta discrimination, 89 Sr and 90 Sr( 90 Y) analysis, flow-cell effluent water (tritium) monitors, and Cherenkov flow-cell analysis. Other techniques discussed are stopped-flow detection and single- and dual-radionuclide analysis in HPLC. The chapter concludes with a comprehensive treatment of hyphenated flow scintillation analysis techniques in conjunction with HPLC and mass spectrometry (HPLC-FSA-MS) and/or nuclear magnetic resonance (NMR) spectroscopy (HPLC-FSA-NMR) for the simultaneous on-line measurement of radioisotope label and the molecular structure of organic compounds, and the applications of this technique in drug metabolism and pharmaceutical and biomedical research.