Certain substituted benzo- and naphthoquinone electron transfer agents are useful in analytical compositions, elements and methods, e.g. for determinations of living cells. These electron transfer agents are capable of being reduced by an analyte, and the reduced electron transfer agent, in turn, reduces another compound providing a detectable species (e.g. a dye). The reduction potential (E.sub.1/2) of the electron transfer agents useful inthis invention is in the range of from about -320 to about +400 mV as measured in an aqueous buffer solution at pH 7.
某些取代苯并和
萘醌电子转移剂在分析组成物、元素和方法中是有用的,例如用于测定活细胞。这些电子转移剂能够被分析物还原,而还原的电子转移剂又进一步还原另一种化合物,提供可检测的物种(例如
染料)。这种发明中有用的电子转移剂的还原电位(E.sub.1/2)在pH 7的
水溶液缓冲溶液中的范围为约-320至约+400 mV。