COMPARISON OF THE LINEAR VANDENBERG RUZIC TRANSFORMATION AND A NONLINEAR FIT OF THE LANGMUIR ISOTHERM APPLIED TO CU SPECIATION DATA IN THE ESTUARINE ENVIRONMENT
COMPARISON OF THE LINEAR VANDENBERG RUZIC TRANSFORMATION AND A NONLINEAR FIT OF THE LANGMUIR ISOTHERM APPLIED TO CU SPECIATION DATA IN THE ESTUARINE ENVIRONMENT
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DOI：
10.1016/0304-4203(94)00041-b
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发表时间：
1995-01-01
期刊：
影响因子：
3
通讯作者：
POORTVLIET, TCW
中科院分区：
文献类型：
--
作者：
GERRINGA, LJA;HERMAN, PMJ;POORTVLIET, TCW
使用差分脉冲阳极溶出伏安法 (DPASV) 和差分脉冲阴极溶出伏安法 (DPCSV) 对河口富含有机物样品进行铜络合测量，结果显示，由于有机质含量较高，数据分散性相对较大。 比较了根据 Langmuir 等温线估计络合参数的两种方法：Van den Berg/Ruzic 的线性变换和根据 Wilkinson 的非线性方法。对于河口样品中的 DPASV 测量，使用线性化方法估计的条件稳定性常数 (K') 值系统地低于使用 Wilkinson 方法估计的值。 Van den Berg/Ruzic 线性化更容易受到异常值或不遵循 Langmuir 等温线模型的数据点的影响。 对于 DPCSV 测量，数据更接近 Langmuir 等温线，无法证明这种差异。首选非线性方法，因为该方法更适合数据的误差结构，其绝对量值恒定。 此外，它的优点是可以一致地计算估计参数的标准误差。
Copper complexation measurements in estuarine organic-rich samples with differential pulse anodic stripping voltammetry (DPASV) and differential pulse cathodic stripping voltammetry (DPCSV) show a relatively large scatter in the data, due to a high organic matter content. Two methods for the estimation of the complexation parameters according to the Langmuir isotherm are compared: the linear transformation of Van den Berg/Ruzic and the non-linear method according to Wilkinson.For DPASV measurements in estuarine samples the values of the conditional stability constant (K'), estimated with the linearization method are systematically lower than those estimated with the Wilkinson method. The Van den Berg/Ruzic linearization is more susceptible to outliers or data points that do not follow the model of the Langmuir isotherm. For DPCSV measurements, where the data followed the Langmuir isotherm more closely, this difference could not be demonstrated.The non-linear method is to be preferred because this method is more suited to the error structure of the data, which is of constant absolute magnitude. Moreover it offers the advantage that the standard error of the estimated parameters can be calculated consistently.