High-throughput Ru(III) analysis using the hydrothermal flow reactor-mediated FIA by the extreme acceleration of Ru(III) complexation with 1,10-phenanthroline.

A new type of flow injection analysis (FIA) combined with a high-temperature reactor maintained at 100-400 °C, namely hydrothermal flow injection analysis (HT-FIA), has been successfully applied to high throughput determination of Ru(III) on the basis of a conventional chromogenic reaction with 1,10-phenothroline (phen). Although this classical chromogenic reaction using phen is sensitive and selective for Ru(III), the complex formation of Ru(phen)(3) requires 2 h. The acceleration using HT-FIA is extraordinary high so that the determination reaction of Ru(III) was successfully shortened to 5 s at 150 °C, where the analytical procedure was accelerated more than 1000-fold. This enabled a high-throughput analysis of Ru(III) with 100 µL sample, of which at least 10 samples can be analyzed within 10 min. The detection limit of Ru(III) determined on the basis of 3 times of standard deviation was 5.3×10(-7) M (53 pmol or 5.4 ng Ru in 100 µL sample). The present study emphasizes the importance of the revival of classical chromogenic reactions, which are potentially valuable but not regarded anymore as useful because they are time-consuming and tedious, to fit for the demand for environmentally harmless analytical techniques.

Flow injection analysis combined with a hydrothermal flow reactor: application to kinetic determination of trace amounts of iridium using a water-soluble porphyrin.

A new type of flow injection analysis (FIA) system combined with an extremely high temperature reactor, namely hydrothermal flow injection analysis (HT-FIA), has been successfully constructed for the first time. Fundamental characteristics of HT-FIA system, such as limit temperature, pressure, and flow rate, were examined as an analytical tool. To demonstrate the potential of HT-FIA, the catalytic activity of Ir(IV) for the degradation of a water-soluble porphyrin, 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid (TPPS), was applied for the determination of trace amounts of Ir(IV). Although the indicator reaction is very slow at room temperature, HT-FIA system enables to accelerate the reaction. A linear calibration curve was acquired at 10(-8)M level of Ir(IV) and the interferences of platinum group metal ions were examined. The detection limit of Ir(IV) was 5.8 × 10(-9)M and a fairly high-throughput analysis, of which more than 30 samples can be analyzed within 80 min, was achieved.