1.1 该测试方法使用信噪比来确定荧光测量系统在测试溶液中硫酸奎宁二水合物的检测限（LOD）时的灵敏度。用硫酸奎宁二水合物溶液获得的结果适用于在室温或室温附近具有大于10nm的激发和荧光带的样品上指定仪器性能。 1.1.1 本试验方法不用于( 1. )仪器性能的严格测试，或( 2. )，以相互比较不同设计的仪器的定量性能。 仪器之间LOD的相互比较通常表示为水拉曼峰值强度与均方根（rms）噪声的比率，如在荧光计上使用350nm的激发波长测量的。该测试方法使用溶液中硫酸奎宁二水合物的激发和发射峰值波长，分别约为350nm和450nm。 1.2 该测试方法已应用于使用非激光、低能激发源的荧光测量系统。无法保证极强的照明不会导致光分解 2. 本试验方法中所建议的化合物。因此，建议不要对高强度光源不加区分地使用该试验方法。本试验方法不旨在确定其他材料的最低可检测量。如果该测试方法扩展到使用其他化学物质，用户应意识到这些其他物质可能会分解或吸附到容器上。 1.3 使用该测试方法的常规荧光计的典型检测限为每毫升1 ng硫酸奎宁。 1.4 1 mg/mL硫酸奎宁二水合物储备溶液的建议保质期为三个月，存放在带塞子的玻璃瓶中。 1.5 以国际单位制表示的值应视为标准值。本标准不包括其他测量单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 当确定荧光物质的极限可检测浓度时，通常需要将光电仪器的读数刻度增加到噪声（即系统的随机波动）变得明显的程度。该噪声将叠加在来自样本的信号上。 4.2 在分子荧光光谱中， 序号 其中， S ，是用样品溶液和空白溶液获得的读数之间的差值，以及 N 是总均方根（rms）噪声。样本的检测极限将由仪器读数给出，该读数给出的信号等于噪声均方根值的三倍。 注2: 影响对应于检测极限的样品浓度的噪声以外的因素包括:激发和发射单色仪的光谱带宽、可集中在样品上的激发光的强度、检测系统收集的荧光的分数、检测系统的响应时间和溶剂的纯度。 样品容器相对于光束的尺寸和布置也很重要，因为它们会影响所需信号和仅产生噪声的外来信号。 注3: 均方根噪声值( N )可以通过如下计算在大约450nm的峰值发射波长下来自样品的信号的一系列读数的标准偏差来获得: 哪里: = 一系列读数的平均值， x（x） = 单个读数的值，以及 n = 读数数量。 或者，可以通过记录一系列读数（峰值- 峰值噪声）并除以通常取为5的因子。 6. 7.

1.1 This test method employs the signal-to-noise ratio to determine the sensitivity of a fluorescence measuring system in testing for the limit of detection (LOD) of quinine sulfate dihydrate in solution. The results obtained with quinine sulfate dihydrate in solution are suitable for specifying instrument performance on samples having excitation and fluorescence bands wider than 10 nm at or near room temperature. 1.1.1 This test method is not intended to be used as ( 1 ) a rigorous test of performance of instrumentation, or ( 2 ), to intercompare the quantitative performance of instruments of different design. Intercomparison of the LOD between instruments is commonly expressed as the ratio of the water Raman peak intensity to the root-mean-square (rms) noise as measured on a fluorometer using an excitation wavelength of 350 nm This test method uses the excitation and emission peak wavelengths for quinine sulfate dihydrate in solution, which are approximately 350 nm and 450 nm, respectively. 1.2 This test method has been applied to fluorescence-measuring systems utilizing non-laser, low-energy excitation sources. There is no assurance that extremely intense illumination will not cause photodecomposition 2 of the compound suggested in this test method. For this reason, it is recommended that this test method not be indiscriminately employed with high intensity light sources. This test method is not intended to determine minimum detectable amounts of other materials. If this test method is extended to employ other chemical substances, the user should be aware of the possibility that these other substances may undergo decomposition or adsorption onto containers. 1.3 A typical LOD for conventional fluorometers using this test method is 1 ng of quinine sulfate per mL. 1.4 The suggested shelf life of a 1 mg/mL stock solution of quinine sulfate dihydrate is three months, when stored in the dark in a stoppered glass bottle. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 When determining the limiting detectable concentration of a fluorescent substance, it is usually necessary to increase the readout scale of a photoelectric instrument to a point where noise (that is, random fluctuations of the system) becomes apparent. This noise will be superimposed upon the signal from the sample. 4.2 In molecular fluorescence spectroscopy, the limit of detection for the sample will be determined by the limiting signal-to-noise ratio, S/N , where the signal, S , is the difference between readings obtained with the sample and blank solutions, and N is the total root-mean-square (rms) noise. The limit of detection for the sample will be given by the instrument readings that give a signal equal to three times the rms value of the noise. Note 2: Factors other than noise affecting the sample concentration corresponding to the limit of detection include: the spectral bandwidths of the excitation and emission monochromators, the intensity of the exciting light that can be concentrated on the sample, the fraction of the fluorescence collected by the detection system, the response time of the detection system, and the purity of the solvent. The size and arrangement of the sample container with respect to the light beams are also important, as they affect both the desired signal and the extraneous signal that only contributes noise. Note 3: The value of rms noise ( N ) can be obtained by calculating the standard deviation of a series of readings of the signal from the sample at the peak emission wavelength at approximately 450 nm as follows: where: = mean of the series of readings, x = value of the individual reading, and n = number of readings. Alternatively, rms noise may be estimated by noting the extreme differences between the members of a series of readings (peak-to-peak noise) and dividing by a factor that is usually taken to be 5. 6, 7