5-Cyano-2,3-di-（p-tolyl）tetrazolium chloride（CTC）是在环境和生态研究中被广泛使用和接受的染料。氧化还原染料CTC由于具有将CTC还原为荧光产物的能力，因此对于评估具有高代谢活性的好氧细菌是一种很好的重要染色剂。通过CTC清除电子传输系统或脱氢酶成分中的电子，可以还原为具有荧光活性的甲electron形式。该染料已与核酸染色染料DAPI结合使用以定量活细菌。 5-Cyano-2,3-di-(p-tolyl)tetrazolium chloride (CTC) is a widely used and accepted dye in environmental and ecological studies. The redox dye CTC is a good vital stain for estimating aerobic bacteria with high metabolic activity due to their ability to reduce CTC to the fluorescent product. The reduction to the fluorescently active formazan form occurs by CTC scavenging for electrons from the components of the electron transport system or dehydrogenases. The dye has been used in conjunction with the nucleic acid staining dye DAPI to quantitate viable bacteria.