Preparation method and application of fluorescent optical fiber sensor suitable for monitoring strongly alkaline pH

The invention belongs to the technical field of fluorescence detection, and relates to a preparation method and application of a fluorescent optical fiber sensor suitable for monitoring strongly alkaline pH. The method comprises the following steps: preparation of silicon dioxide fluorescent nanoparticles: covalently adding a 1, 8-naphthalimide fluorescent dye to nano silicon dioxide to prepare the silicon dioxide fluorescent nanoparticles; preparation of PVA/silicon dioxide sol-gel: during preparation of the PVA/silicon dioxide sol-gel, embedding and fixing the silicon dioxide fluorescent nanoparticles in the PVA/silicon dioxide sol-gel through a hydrolytic condensation reaction; optical fiber coating: removing a protective layer from one end of the quartz bare fiber, and carrying out hydroxylation and silanization treatment; and forming a uniform thin film on the end part of the hydroxylated/silanized optical fiber by adopting a dip-coating method, so as to prepare the fluorescent optical fiber sensor suita