Jones Willis B, Donati George L, Calloway Clifton P, Jones Bradley T
Department of Chemistry, Wake Forest University , Winston-Salem, North Carolina 21709, United States.
Anal Chem. 2015 Feb 17;87(4):2321-7. doi: 10.1021/ac504152x. Epub 2015 Jan 30.
Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES.
标准稀释分析（SDA）是一种新型校准方法，可应用于大多数能接受液体样品并能同时监测两个波长的仪器技术。它结合了标准加入法和内标法的传统方法。因此，它能同时校正基体效应以及因样品大小、取向或仪器参数变化引起的波动。使用电感耦合等离子体发射光谱法（ICP OES）时，SDA每个样品仅需200秒。既不需要制备一系列标准溶液，也不需要构建通用校准曲线。分析是通过在单个容器中混合两种溶液来进行的：第一种溶液含有50%的样品和50%的标准混合物；第二种溶液含有50%的样品和50%的溶剂。当第一种溶液被第二种溶液稀释时实时收集数据。结果用于绘制以分析物与内标信号比为纵坐标、以内标浓度的倒数为横坐标的曲线。样品中分析物的浓度由该曲线的斜率和截距之比确定。该方法已应用于通过分子吸收光谱法测定漱口水中的FD&C蓝色一号染料，以及通过ICP OES测定漱口水中、葡萄酒、可乐、硝酸和水中的八种金属。SDA的准确度和精密度均优于使用ICP OES的外标法、标准加入法和内标法。
