水杨醛缩7-氨基-8-羟基喹啉-5-磺酸（简称S7N8Q5S）在酸性介质中分解，产物呈现荧光，V（V）对该反应具有催化作用，本文建立了催化荧光法测定痕量钒的新方法。体系在PH=2的柠檬酸钠-盐酸缓冲溶液中，λex／λem=342／499（nm）。测定V（V）的最佳反应条件为0.04％S7NSQ5S5.0mL，5％KBrO35．0mL，缓冲溶液5．0mL，90℃加热5min。V（V）含量在12.0～40.0μg／L的范围内有良好的线性。将该方法用于钒铬钢样品及水样中痕量钒的测定，结果满意。本文还详细探讨了反应机理。 Salicylaldehyde condensed 7-amino-8-hydroxyquinoline-5-sulfonic acid (referred to as S7N8Q5S) in acidic medium decomposition, the product showed fluorescence, V (V) has a catalytic effect on the reaction, the establishment of a catalytic fluorimetric assay A new method of trace vanadium. The system has a λex / λem = 342/499 (nm) in pH = 2 sodium citrate-hydrochloric acid buffer. The optimal reaction conditions for the determination of V (V) were 0.04% S7NSQ5S5.0mL, 5% KBrO35.0mL, buffer solution 5.0mL and 90 ℃ heating 5min. V (V) content in the 12.0 ~ 40.0μg / L range of good linearity. The method was applied to the determination of trace vanadium in vanadium-chromium steel samples and water samples with satisfactory results. This article also discusses the reaction mechanism in detail.