We examined photoinduced electron transfer (PET) in multicomponent aqueous suspensions composed of tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy) 3 2+ , photocatalyst), methylviologen (1,1′-dimethyl-4,4′-bipyridinium dication, MV 2+ , electron acceptor), and ethylenediamine tetraacetate (EDTA, sacrificial electron donor) together with particles of smectite-type clays although previous studies indicated inhibition of the electron transfer from Ru(bpy) 3 2+ to MV 2+ in the presence of clay particles. Clays with different lateral particle sizes were compared: hectorite (Hect) and saponite (Sapo) with small particle sizes (∼30 nm) and fluorohectorite (FH) and montmorillonite (Mont) with large particle sizes (>0.1 μm). Clay particles were flocculated and were settled in many cases after the addition of Ru(bpy) 3 2+ , MV 2+ , and EDTA species, and the Ru(bpy) 3 2+ and MV 2+ cations were almost all adsorbed on the clay particles. When Hect and Sapo were used, reduction of MV 2+ was observed on the aggregated clay particles upon visible light irradiation indicating the occurrence of PET from Ru(bpy) 3 2+ to MV 2+ . However, the reaction was not observed for the samples where the clay particles were not settled. When FH and Mont were used, PET was not observed irrespective of the flocculation of clay particles. These results demonstrated that PET from Ru(bpy) 3 2+ to MV 2+ in the presence of clay particles is possible when the clay particles with small sizes are appropriately aggregated to allow interparticle electron hopping.

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2013 年 1 月 29 日 受付・2013 年 5 月 13 日 受理) 要 旨 手指衛生手技としてのスクラブ法では流水下で手を擦り合わせることによる物理的除去効果が期 待され，その評価には蛍光物質を用いた目視確認が汎用されているが，洗い残しの定量的な把握は 困難であった．そこで，本研究では一定量の蛍光物質を手指に塗布して手洗いを行い，手洗いによ り水中に移行した蛍光物質を定量し，質量除去率を算出する手法について検討した．その結果，洗 い残し面積を目視して算出した面積除去率よりも質量除去率の方が有意に低かったとともに，面積 除去率と質量除去率の乖離の程度が被験者により大きく異なっており，目視確認による主観的評価 の問題点が明らかとなった．よって，手指衛生手技における物理的除去効果を定量的に把握するこ とは評価の客観性向上に資するものと考えられ，各種介入効果や手指衛生手技の具体的手順の検討 等に際し，質量除去率という指標が有用である可能性が示唆された． Key words感染制御，手指衛生，定量的評価，スクラブ法 図 質量除去率測定フロー-202 - AbstractA physical removal eŠect can be expected by the scrub method used as a hand hygiene technique, but quantitative evaluation of the eŠect is di‹cult by visual inspection using ‰uorescent material. This study examined the mass extraction ratio by measurement of ‰uorescent material in the water after washing the hands with aˆxed quantity of ‰uorescent material. As a result, the mass extraction ratio was signiˆcantly lower than the area extraction ratio by visual inspection, and the deviation of the area extraction ratio and mass extraction ratio were signiˆcantly diŠerent from individual to individual, so that the problem with subjective evaluation by visual inspection was revealed. Therefore, the physical removal eŠect as the mass extraction ratio in hand hygiene techniques apparently improves the objectivity of evaluation, and the mass extraction ratio is a useful indicator to evaluate the eŠects of interventions and hand hygiene techniques.