Abstract. Polyacrylamide gels are unstable in 50-pm internal diameter capillaries at electric fields greater than about 500 V cm-l due to the formation of bubbles, which destroy the separation. We describe the use of a modified polyacrylamide capillary gel that is stable at electric fields of at least 800 V crn-l. This capillary gel produces sequencing rates of 3,200 bases h-' for fragments up to 250 bases in length; a total of 7 min are required to separate fragments of 250 bases in length. Longer fragments tend to coelute and do not generate useful sequencing information. This sequencing rate is a factor of 40 times higher than that produced by conventional sequencing gels and a factor of 3 faster than previous reports in the literature.
The application of quaternary ammonium functionalized polymers to voltammetric analysis is described. A glassy carbon electrode coated with a thin film of poly(trihexylviny1ben-zylammonium chloride) exhibited attractive permselectivity to uric acid. Typically, this polymer-modified electrode yielded a linear voltammetric response to uric acid in the concentration range of 1-10 pM. The ion exchange properties of poly(trihexylvinylbenzy1am-monium chloride) was related to the Gibbs-Donnan equation. Also, chronoamperometry was used to probe the charge-transport and response mechanisms within this type of ionic polymer film.
Generic capillary electrophoresis (CE) conditions have been implemented for chiral separations in early pharmaceutical development. The chiral CE separations of several pharmaceutical samples at different stages of development, i.e., discovery, process chemistry, and investigative new drug application, have been obtained using sulfated beta-cyclodextrin (CD). Several sulfated beta-CDs have been screened to select an appropriate enantioselective agent. The use of a generic CE method allows for a convenient and rapid chiral recognition of different weak bases, with minimal or no method development. CE using sulfated beta-CD for the chiral separation of N-benzoyl methyl piperazine has been validated for linearity, precision, accuracy, limits of detection and quantitation (LOD, LOQ). Although less sensitive than a specific liquid chromatography method using a Chiralpak AD column, the overall performance of the chiral CE method was found comparable. Validation data demonstrate that a LOD of 0.1%, sufficient to fulfill regulatory requirements, is achievable by chiral CE.
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