The persistent microbicidal effect in water exposed to the corona discharge

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• 作者：Jaroslav Jul&aacute ; k^a ; ^{jaroslav.julak@lf1.cuni.cz} ; Vladimí ; r Scholtz^b ; So艌a Kotú ; 膷ov&aacute ; ^b ; Olga Janou&scaron ; kov&aacute ; ^a
• 关键词：Corona discharge ; Low temperature plasma ; Persistent microbicidal effect
• 刊名：Physica Medica
• 出版年：2012
• 期刊代码：256_11201797
• 类别：med
• 出版时间：July, 2012
• 卷：28
• 期：3
• 页码：230-239
• 文件大小：1354 K

摘要

This article describes and particularly explains a new phenomenon of persistent microbicidal effect of water previously exposed to the low-temperature plasma, which cannot be attributed to the acidification only. The direct microbicidal action of plasma is well documented, being mediated by number of reactive particles with a short lifetime. However, we observed the microbicidal effect also in exposed water stored for a month, where it must be mediated by stable particles. In water and in phosphate-buffered saline, the formation of NO_x and corresponding acids, H₂O₂ and O₃ was confirmed after exposition to the low-temperature plasma generated in air by DC negative glow corona and positive streamer discharge. The time course of acidification, H₂O₂ and O₃ formation were deremined. Except uncertain traces of HCN, SIFT-MS analysis of exposed liquids reveals no additional reactive compounds. The microbicidal effect persists almost unchanged during 4 weeks of storage, although O₃ completely and H₂O₂ almost disappears. Staphylococcus epidermidis and Escherichia coli were inactivated within 10聽min of incubation in exposed liquids, Candida albicans needs at least 1聽h. The solutions prepared by artificial mixing of reactive compounds mimic the action of exposed water, but in lesser extent. The acid milieu is the main cause of the microbicidal effect, but the possibility of still unidentified additional compound remains open.