在pH 5.5的乙酸盐缓冲溶液中，并在十二烷基苯磺酸钠的存在下，曙红Y与罗丹明B之间发生能量转移，导致罗丹明B的荧光增强；而在40 ℃温度条件下，当有锰（Ⅱ）存在时，罗丹明B在波长576 nm处的荧光发射发生猝灭现象。进一步试验表明，当在激发波长为508 nm和发射波长为576 nm的条件下，上述荧光猝灭的强度ΔF，即试液中无锰（Ⅱ）及有锰（Ⅱ）存在时所测得的荧光强度F₁及F₂之差，与锰（Ⅱ）的浓度在1.0×10^-8~2.0×10^-7mol·L^-1范围内呈线性关系，检出限（3s/k）为4.0×10^-9mol·L^-1。据此提出了测定样品中痕量锰（Ⅱ）的荧光光谱法。应用此方法对同一试样中痕量锰作了测定，并以此样品作基体，用标准加入法进行回收试验，测得回收率为106%，样品测定值的相对标准偏差（n=11）为4.8%。

In an acetate buffer solution of pH 5.5 and in the presence of sodium dodecyl benzene sulfonate, enhancement of fluorescence intensity of rhodamine B was observed due to the occurrence of energy transfer between eosin Y and rhodamine B. It was shown further that when under a temperature of 40 ℃ and in the presence of trace amounts of Mn(Ⅱ), the fluorescence of rhodamine B emilted at 576 nm was quenched and that linear relationship was obtained between the magnitude of the fluorescence quenching, ΔF [which is the difference of fluorescence intensity of the test solution without Mn(Ⅱ), F₁ and of that with Mn(Ⅱ), F₂ measured at λ_ex=508 nm and λ_em=576 nm] and the concentration of Mn(Ⅱ) ion in the range of 1.0×10^-8-2.0×10^-7mol·L^-1, with detection limit (3s/k) of 4.0×10^-9mol·L^-1. Based on these facts, a method of fluorescent spectroscopy determination of trace amount of Mn(Ⅱ) in samples was proposed. Tests for precision and recovery (by standard addition method) were performed by analyzing a substantial sample with the proposed method, giving values of RSD (n=11) of 4.8% and of recovery of 106%.