Evaluation of light‐scattering detectors for size exclusion chromatography. II. Light‐scattering equation selection
Evaluation of light‐scattering detectors for size exclusion chromatography. II. Light‐scattering equation selection
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DOI：
10.1002/app.1993.070490805
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发表时间：
1993-08
影响因子：
3
通讯作者：
L. Jeng;S. Balke
中科院分区：
文献类型：
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作者：
L. Jeng;S. Balke
用于尺寸排除色谱的新的多安激光散射（购物中心）探测器有望在每个保留体积上都可以简单地测量重量平均分子量（MW）和循环半径（RG）。解释原始数据以提供这些研究的研究。使用了聚乙烯的聚苯乙烯和高温分析。根据标准出发的简单置信区间，以查看MW和RG相互依赖的影响。 Zimm图）仅评估了回归模型中包含的数据的效果 - 由于外推到零温度的缩短，在室温下的精度缩短了探测器角度，因此发现了平均重量值置信区间仅提供与更精确的JCR的公平近似值。为了区分这些值的有意义的相关性，应在光片段研究中进行更常见的JCR。
A new multiangle laser light-scattering (MALLS) detector for size exclusion chromatography promises simultaneous measurement of both weight-average molecular weight (Mw) and radius of gyration (rg) at each retention volume across the chromatogram. However, there are a variety of ways of interpreting the raw data to provide these results. This study examines variations of three different rearrangements of the basic light-scattering equation. Data from a room temperature analysis of polystyrene and a high-temperature analysis of polyethylene were used. The degree of fit of each equation to the data and the precision of the Mw and rg values are evaluated. To define precision, joint confidence regions (JCRs) were calculated and compared to simple confidence intervals based upon standard deviations in order to see the effect of interdependence of Mw and rg. Results showed that the Debye equation was superior to the inverse Debye equation (similar to the Zimm plot) for the interpretation of MALLS data. The effect of the quantity of data included in the regression model was also assessed. Use of only the most precise four detector angles was compared to use of a full set of 15 angles. Precision of weight-average molecular weight values was found to be improved as the detector angle decreased because of the shortened extrapolation to zero angle. Precision at room temperature was much superior to that at high temperature. Use of simple confidence intervals was shown to provide only a fair approximation to the more accurate JCR. The “natural scatter” of data shown by the JCR generally shows the same trend as do plots in the literature of Mw vs. rg. Thus, it is concluded that JCRs should be more often calculated in light-scattering studies in order to distinguish random scatter from meaningful correlations of these values. © 1993 John Wiley & Sons, Inc.