Dean S. Burgi

Bio: Dean S. Burgi is an academic researcher from Varian Associates. The author has contributed to research in topics: Capillary electrophoresis & Capillary action. The author has an hindex of 9, co-authored 9 publications receiving 886 citations.

Methods For Calculating the Internal Temperature of Capillary Columns During Capillary Electrophoresis

Abstract: The internal temperature, the buffer viscosity and the efficiency of heat removal from a silica capillary can be calculated by measuring the differential electroosmostic mobility at a low voltage and a high voltage. the calculated temperature is plotted vs the power generated by the electrophoretic instrument and yields a linear relationship when the power is below 3.0 W. the temperature can also be calculated using the conductivity of the solution. the two methods provide the same temperature, which compares well with literature values. A rule of thumb for a quick calculation of internal temperatures is that a power of 0.1 W

Temperature measurement in microfluidic systems using a temperature-dependent fluorescent dye.

Abstract: A technique is described for the measurement of fluid temperatures in microfluidic systems based on temperature-dependent fluorescence. The technique is easy to implement with a standard fluorescence microscope and CCD camera. In addition, the method can be used to measure fluid temperatures with micrometer spatial resolution and millisecond time resolution. The efficacy of the method is demonstrated by measuring temperature distributions resulting from Joule heating in a variety of microfluidic circuits that are electrokinetically pumped. With the equipment used for these measurements, fluid temperatures ranging from room temperature to 90 °C were measured with a precision ranging from 0.03 to 3.5 °Cdependent on the amount of signal averaging done. The spatial and temporal resolutions achieved were 1 μm and 33 ms, respectively.

Fabrication of plastic microfluid channels by imprinting methods.

Abstract: Microfluidic devices have been fabricated on poly(methyl methacrylate) substrates by two independent imprinting techniques. First-generation devices were fabricated using a small-diameter wire to create an impression in plastics softened by low-temperature heating. The resulting devices are limited to only simple linear channel designs but are readily produced at low cost. Second-generation devices with more complex microchannel arrangements were fabricated by imprinting the plastic substrates using an inverse three-dimensional image of the device micromachined on a silicon wafer. This micromachined template may be used repeatedly to generate devices reproducibly. Fluorescent analtyes were used to demonstrate reproducible electrophoretic injections. An immunoassay was also performed in an imprinted device as a demonstration of future applications.

Monitoring amplification of DNA during PCR

Abstract: Methods of monitoring hybridization during polymerase chain reaction are disclosed. These methods are achieved with rapid thermal cycling and use of double stranded DNA dyes or specific hybridization probes. A fluorescence resonance energy transfer pair comprises fluorescein and Cy5 or Cy5.5. Methods for quantitating amplified DNA and determining its purity are carried out by analysis of melting and reannealing curves.

Sample stacking of an extremely large injection volume in high-performance capillary electrophoresis

Abstract: Sample stacking is a sample on-column concentration technique in high-performance capillary electrophoresis (HPCE). However, the amount of sample which can be loaded into the column in conventional sample stacking is rather limited because of disturbance caused by the low-concentration sample buffer. This report describes a technique of stacking an extremely large sample volume into narrow bands. The technique is based on the principal that the local electrophoretic velocity of the ions inside the sample buffer is much faster than the bulk electroosmotic velocity of the solution

Capillary electrophoresis on microchip

Abstract: Capillary electrophoresis and related techniques on microchips have made great strides in recent years. This review concentrates on progress in capillary zone electrophoresis, but also covers other capillary techniques such as isoelectric focusing, isotachophoresis, free flow electrophoresis, and micellar electrokinetic chromatography. The material and technologies used to prepare microchips, microchip designs, channel geometries, sample manipulation and derivatization, detection, and applications of capillary electrophoresis to microchips are discussed. The progress in separation of nucleic acids and proteins is particularly emphasized.