BOUNDARY ANALYSIS IN SEDIMENTATION TRANSPORT EXPERIMENTS - A PROCEDURE FOR OBTAINING SEDIMENTATION COEFFICIENT DISTRIBUTIONS USING THE TIME DERIVATIVE OF THE CONCENTRATION PROFILE
BOUNDARY ANALYSIS IN SEDIMENTATION TRANSPORT EXPERIMENTS - A PROCEDURE FOR OBTAINING SEDIMENTATION COEFFICIENT DISTRIBUTIONS USING THE TIME DERIVATIVE OF THE CONCENTRATION PROFILE
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DOI：
10.1016/0003-2697(92)90316-y
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发表时间：
1992-06-01
影响因子：
2.9
通讯作者：
STAFFORD, WF
中科院分区：
文献类型：
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作者：
STAFFORD, WF
介绍了一种由沉降速度浓度剖面的时间导数计算沉降系数分布的方法。希望使用时间导数(∂c∂t)r而不是径向导数(∂c∂r)t，因为它独立于对光学基线的时间不变贡献。缓慢变化的基线变化也显著减少。表观沉降系数分布g∗(S)可由(∂c∂t)ras[公式：见正文]计算得到，其中S是沉降系数，ω是转子的角速度，c0是初始浓度，r是半径，rMis是半月面的半径，t是时间。本文给出了一种计算g∗(S)t的迭代方法，它考虑了高原地区对(∂c∂t)r的贡献，从而得到(∂c∂t)r。用这种方法得到的g∗(S)的值与由径向导数计算的g∗(S)的值相同，都在计算的舍入误差范围内。使用(∂c∂t)r而不是(∂c∂r)t导致从分析超离心机的UV光电扫描仪和瑞利光学系统获得的数据的信噪比显著增加(>；10倍)。以抗原-抗体体系为例，说明了(∂，c，∂，t)r在边界分析中计算表观沉降系数分布的应用。
A procedure is described for computing sedimentation coefficient distributions from the time derivative of the sedimentation velocity concentration profile. Use of the time derivative, ( ∂c ∂t )r, instead of the radial derivative, ( ∂c ∂r )t, is desirable because it is independent of time-invariant contributions to the optical baseline. Slowly varying baseline changes also are significantly reduced. An apparent sedimentation coefficient distribution (i.e., uncorrected for the effects of diffusion), g∗(s) , can be calculated from ( ∂c ∂t )ras [Formula: see text] where s is the sedimentation coefficient, ω is the angular velocity of the rotor, c0is the initial concentration, r is the radius, rmis the radius of the meniscus, and t is time. An iterative procedure is presented for computing g∗(s)tby taking into account the contribution to ( ∂c ∂t )rfrom the plateau region to give ( ∂c ∂t )corr. Values of g∗(s)tobtained this way are identical to those of g∗(s) calculated from the radial derivative to within the roundoff error of the computations. Use of ( ∂c ∂t )r, instead of ( ∂c ∂r )t, results in a significant increase (>10-fold) in the signal-to-noise ratio of data obtained from both the uv photoelectric scanner and Rayleigh optical systems of the analytical ultracentrifuge. The use of ( ∂c ∂t )rto compute apparent sedimentation coefficient distributions for purposes of boundary analysis is exemplified with an antigen-antibody system.