在总体积为50.0 mL的溶液中加入0.1 mol·L^-1硫酸溶液2.0 mL，0.1 mol·L^-1碘化钾溶液2.0 mL及1.0×10^-4mol·L^-1罗丹明B溶液5.0 mL，以荧光激发波长为365 nm，在荧光最大发射波长580 nm处可测得罗丹明B发出的明显荧光。当在此条件下，加入过氧乙酸能使其荧光强度迅速减弱，且其减弱程度与过氧乙酸的浓度在4.2×10^-7~5.0×10^-5mol·L^-1内呈线性关系，并根据10次空白溶液的平行测定计算得到此方法的检出限（3s/k）为2.0×10^-8mol·L^-1。据此提出了罗丹明B荧光猝灭法测定消毒液中过氧乙酸的含量。分析时取样品溶液0.25 mL，滴加0.01 mol·L^-1高锰酸钾溶液至溶液呈稳定的浅粉红色，加水稀释至500.0 mL，制得样品待测液。取此溶液1.0 mL，加入于上述反应溶液中（在加入碘化钾溶液之后），放置15 min后按上述方法操作。在3件不同来源的样品按此方法进行分析并进行加标回收试验，测得回收率在96.5%~97.5%之间，测定总量的相对标准偏差（n=6）在1.3%~2.6%之间。所测得此3个样品的过氧乙酸含量均与其标示量相符。由于过氧乙酸标准溶液的不稳定性导致所测得回收率均低于100%。

Fluorescence with definite intensity was emitted by rhodamine B with λ_ex of 365 nm and λ_em of 580 nm in a reaction system containing 2.0 mL of 0.1 mol·L^-1 H₂SO₄ solution, 2.0 mL of 0.1 mol·L^-1 KI solution and 5.0 mL of 1.0×10^-5mol·L^-1 rhodamine B solution, with total volume of the reaction solution of 50.0 mL. When peroxy acetic acid was added to the reaction system, the fluorescence was quenched instantly. It was found that linear relationship was kept between the magnitude of decrease of fluorescence and concentration of peroxy acetic acid in the range from 4.2×10^-7 to 5.0×10^-5mol·L^-1. Detection limit (3s/k) found by 10 parallel determinations of blank solutions and the standard deviation calculated was 2.0×10^-8mol·L^-1. Based on this phenomenon, a method of determination of peroxy acetic acid in disinfectant by fluorescence quenching of rhodamine B was proposed. The analyte solution was prepared by diluting 0.25 mL of the disinfectant with water to 500.0 mL after oxidation by adding 0.01 mol·L^-1 KMnO₄ solution dropwise until a stable and light pink color persisted in the solution. An aliquot of 1.0 mL of this solution was added to the reaction system (after the addition of KI solution), and kept the reaction solution standing for 15 min, then the analysis was carried on as described in the procedure. Three disinfectant samples from different factories was analyzed by the proposed method giving results in conformity with the labelled values given. Tests for recovery and precision were made by standard addition to the 3 samples as matrixes, giving results of recovery in the range of 96.5% to 97.5%, and RSDs (n=6) ranged from 1.3% to 2.6%. Somewhat lower recoveries were obtained due to instability of the peroxy acetic acid standard solution.