Application of a Steady-State Flow Analysis to a Long-Period Reaction in a Continuous-Flow System

Abstract

Abstract A steady-state flow analysis (SSFA) has been developed and applied to the determination of trace amounts of manganese in an unsegmented flow system. Because this method is no longer characterized by the sample zone dispersion and/or the sequentiality, sharp decreases in the analytical speed and sensitivity for long-period reactions can be avoided. This method has been demonstrated to be useful, especially for long-period reactions in continuous-flow systems. Optimizations of a steady-state flow manifold are described in detail, and determinations of sub-nanogram manganese have been carried out in a long-period reaction of manganese-catalyzed malachite green with periodate. As a result, several improvements were made in comparison with an ordinary flow-injection method: The detection limit decreased to ca. one-thirtieth, the analytical speed was ca. 2.5 times, the coil length was one-twelfth, the dispersion coefficient was ca. one-eighteenth, while the reaction time was ca. 2.3 times. Determinations of manganese in reference materials of NIES of Japan were performed, and the results were obtained as follows: Manganese in μg g−1 in sargasso, tea leaves, and rice flour (containing high cadmium content) were 22.0 ± 2.6, 686 ± 19, and 35.7 ± 1.7, respectively. These results correspond well with their reference values.