Bart Childs

Peak Shape Distortions in the Capillary Electrophoretic Separations of Strong Electrolytes When the Background Electrolyte Contains Two Strong Electrolyte Co-Ions

A series of 25 mM phosphate buffer background electrolytes were prepared from phosphoric acid and mixtures of lithium hydroxide and tetrabutylammonium hydroxide as pH adjusters and sources of background electrolyte co-ions. These background electrolytes were used for the capillary electrophoretic separation of quaternary ammonium analytes. Abnormally distorted peaks, different from the simple characteristic triangular peaks usually attributed to electromigration dispersion, were observed. In order to understand the origin of the greatly distorted peaks, capillary electrophoretic separations with two co-ion background electrolytes were numerically simulated using a mathematical model of the electrophoretic process. Generalized peak shape rules were derived from the simulations which can be used to predict the shape of the analyte, co-ions, and counterion concentration peaks, as well as the local electric field strength changes. Abnormal peak shape and peak disappearance can occur when the analyte peak and the noncomigrating system peaks overlap.

Peak shape distortions during capillary electrophoretic separations of multicomponent samples in two co-ion buffers

Abstract During the capillary electrophoretic separation of a five-component quatternary ammonium analyte sample in two co-ion background electrolytes prepared from phosphoric acid, lithium hydroxide and tetrabutylammonium hydroxide, grossly distorted analyte peaks were observed. The electropherograms were successfully simulated using an earlier mathematical model of electrophoresis that was extended to handle up to eight nonprotic sample ions and two nonprotic background electrolyte co-ions. Peak shape distortion closely followed the predictions made during the recently described simulations of single analyte-two co-ion background electrolyte systems. Peak shape distortion was shown to depend on the relative mobilities of the particular analyte, the non-comigrating system peak and the governing co-ion. Severe peak shape distortion could occur in every multiple co-ion background electrolyte, such as in the indirect detection background electrolytes and charged interacting agent-containing background electrolytes, when certain analyte peaks and the non-comigrating system peaks overlap.

Literate programming and documentation reuse

Object-oriented programming has brought many advantages to the software engineering community. The reuse of existing software components and application frameworks can improve the productivity in software development considerably. The same object-oriented techniques, i.e., inheritance and information hiding, that ease reusing software, can be applied to documentation and thus, enable its reuse. One can document each software component-regardless of what a component is-from scratch. This leads to multiple documentation of features that are multiply reused. One can also describe a components differences to other components. This seems logical for the systems documentation of object-oriented software. However, as is shown, this kind of reuse can not only be applied to source-code related documentation, but also to documentation, where there is no source code involved at all, e.g., user documentation. We describe the concepts for documentation reuse, how these concepts can be realized with a literate programming tool, and the application of documentation reuse.

An Analysis of Power Series Operators

An analysis of some common power series operations is given in terms of the length of the truncated power series. It is shown that functions on power series can be efficiently computed. This can be the basis of accurate, efficient integrators for ordinary differential, integral, and integro-differential equations.