不同pH值下有机酸碱对发光菌的急性毒性

测定了33种有机酸碱化合物在不同pHT(5．0、7．0、9．0)对发光菌的急性毒性(半数发光抑制浓度，15min-EC50。)。结果表明，胺类化合物对发光菌的毒性随pH的升高而增大；酚类和苯甲酸类的毒性随pH的升高而减小，这与不同pH下有机酸碱的电离程度有关。有机酸碱的生物毒性主要是由分子态引起，但离子态作用不可忽略。相同pH下，有机酸碱的生物毒性随取代基团的种类、个数及取代位置而不同。并在此基础上初步探讨了有机酸碱的毒性机制。

Acute Toxicities of Organic Acids and Bases to Photobacterium Phosphoreum at Different pH

The acute toxicities(the concentration values causing a 50% inhibition of bioluminescence after 15 minutes,abbreviated 15min EC 50 )of 33 organic acids and bases to photobacterium phoshoreum were measured at different pH( 5.0, 7.0,9.0).The results showed that the toxicities of anilines increased with pH whereas the toxicites of phenols and benzoic acids decreased with pH.This phenomenon is related to the ionization degree of organic acids and bases.The nonionized form of chemical plays an important role in its toxicity.At the same pH,the toxicites of organic acids and bases vary with the kind,the number and the position of substituents.The toxic mechanisms of organic acids and bases were preliminarily discussed.