PubMed · 8746676
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K D Altria. 1996. Typical operating procedures.. https://doi.org/10.1385/0-89603-315-5%3A21
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Capillary array electrophoresis (CAE) microplates that can analyze 96 samples in less than 8 min have been produced by bonding 10-cm-diameter micromachined glass wafers to form a glass sandwich structure. The microplate has 96 sample wells and 48 separation channels with an injection unit that permits the serial analysis of two different samples on each capillary. An elastomer sheet with an 8 by 12 array of holes is placed on top of the glass sandwich structure to define the sample wells. Samples are addressed with an electrode array that makes up the third layer of the assembly. Detection of all lanes with high temporal resolution was achieved by using a laser-excited confocal fluorescence scanner. To demonstrate the functionality of these microplates, electrophoretic separation and fluorescence detection of a restriction fragment marker for the diagnosis of hereditary hemochromatosis were performed. CAE microplates will facilitate all types of high-throughput genetic analysis because their high assay speed provides a throughput that is 50 to 100 times greater than that of conventional slab gels.
Chiral separations employing molecular imprint polymer (MIP) stationary phases in both open tubular liquid chromatography (OT-LC) and capillary electrochromatography (OT-CEC) are demonstrated. MIPs are highly crosslinked polymers containing spatial and functionality memory of template molecules which provide a higher degree of selectivity when used as stationary phases for chromatographic separations. Thin films of molecular imprinted polymers bonded to the inner walls of 25 microm ID fused-silica capillaries were prepared using an in situ polymerization technique developed in our laboratory that allows the use of conventional fused-silica capillaries with polyimide outer coatings. The success rate in preparing such open tubular columns was about 70%. Methacrylic acid and 2-vinyl pyridine were chosen as functional monomers, and either ethylene dimethacrylate or trimethylol propane trimethacrylate was used as the crosslinker. Toluene was employed as the porogen. Effects of polymerization conditions on column preparation and chromatographic performance were studied. Enantiomeric separations of D- and L-dansyl phenylalanines were achieved in both OT-LC and OT-CEC modes with good selectivity and efficiencies. Both types of separations may be performed on the same column using a single commercial instrument.
Polyethyleneimine (PEI, molecular weight 6 x 10(5) - 1 x 10(6)) is applied as a positively charged pseudostationary phase for electrokinetic chromatography (EKC) of uncharged mono- and oligophenols. EKC is carried out in PEI-coated fused-silica capillaries (with electroosmotic flow directed towards the anode) in 2-(N-morpholino)ethanesulfonic acid (MES) buffer (pH 7.0, 20 mM) with PEI added to the solution in concentrations up to 0.70% w/v. The pseudostationary phase leads to a retardation of the solutes mainly according to the number (and the position) of the OH-groups of the separands, and is not influenced significantly by methyl groups. For 0.70% w/v PEI solution, for instance, the relative retention, rho, has values between 0.33 and 0.53. For the systems with the highest resolution of the separands (0.25-0.30% PEI) 190,000 plates per meter are observed. The results indicate that the separation selectivity is mainly caused by ion-dipole interactions between the OH-groups of the solutes and the pseudostationary phase.