Abstract: Enclosed (or at least substantially enclosed) microswitch cavities can be constructed with suitable channels, and in some instances vents, to allow for the transport of fluidic microswitch components to the cavities. This generally allows for fluid transport to cavities that are largely completed. Various techniques, including formation of pressure gradients and electrowetting, can be used to transport fluid along the channels. Additionally, structures and techniques for providing fluid to multiple microswitches and for providing fluid in desired amounts to microswitches are disclosed.

Abstract: The present invention relates to a microfluidic device for separating the components of a fluid sample. A cover plate is arranged over the first surface of a substrate, which, in combination with a microchannel formed in the first surface, defines a separation conduit for separating the components of the fluid sample. An inlet port in fluid communication with the separation conduit allows a mobile phase containing a gradient of a selected mobile-phase component to be introduced from an integrated gradient-generation means to the separation conduit. A method is also provided for separating the components of a fluid sample using a mobile phase containing a gradient of a selected mobile-phase component, wherein the gradient is generated within a small volume of mobile phase.

Abstract: The present invention relates to a microdevice for separating the components of a fluid sample. A cover plate is arranged over the first surface of a substrate, and, in combination with a microchannel formed in the first surface, defines a separation conduit for separating the components of the fluid sample. A sample inlet port in fluid communication with the conduit allows a fluid sample introduced from a sample source to be conveyed in a defined sample flow path such that the sample fluid travels, in order, through the sample inlet port, the separation conduit and a sample outlet port. The microdevice also includes an integrated introducing means for controllably introducing a volume of the fluid sample from a sample source into the sample inlet port and through the separation conduit. A method for separating the components of a fluid sample using the microdevice is also provided.

Abstract: Devices comprising a mechanism for selectively diverting a portion of a mobile phase flowing through a mobile-phase transporting conduit to a fluid-transporting conduit comprising a stationary phase for separating sample components are disclosed, as well as systems and methods for using the same.

Abstract: A microfluidic system including a chip sensor and an SPR optical detector. The chip sensor may be made a non-transparent material, such as polyimide or silicon, allowing non-visible radiation produced by the SPR optical detector to pass through and interact with a surface plasmon generating layer on the chip sensor.

Abstract: Disclosed is a multi-substrate microfluidic device for performing multi-dimensional separation of sample components, as well as systems and methods for using the same.

Abstract: An ion source for an analytical instrument is described. The ion source comprises a capillary tip and counter-electrode interface and a feedback loop control device connected to the capillary tip and counter-electrode interface. The feedback loop control device comprises a transimpedance amplifier, a DC de-coupler, a frequency to voltage converter, a controller, and a voltage-controlled high-voltage power supply that provides a tip to counter-electrode voltage to the capillary tip and counter-electrode interface. The feedback loop control device measures the modulation frequency of ionization currents and provides a feedback adjustment of the tip-to-counter-electrode voltage to maintain ionization efficiency.

Abstract: An electrospray device for a mass spectrometry system is described. The electrospray device comprises a body portion and a tip portion extending from the body portion. The tip portion comprises a polymeric material. The electrospray device also comprises a hydrophobic coating substantially selectively covering the tip portion.

Abstract: An electrospray device for a mass spectrometry system is described. The electrospray device comprises a body portion and a tip portion extending from the body portion. The tip portion comprises a polymeric material. The electrospray device also comprises a hydrophobic coating substantially selectively covering the tip portion. The hydrophobic coating is electrically nonconductive.

Abstract: An ion source for an analytical instrument is described. The ion source comprises a capillary tip and counter-electrode interface and a feedback loop control device connected to the capillary tip and counter-electrode interface. The feedback loop control device comprises a transimpedance amplifier, a DC de-coupler, a frequency to voltage converter, a controller, and a voltage-controlled high-voltage power supply that provides a tip to counter-electrode voltage to the capillary tip and counter-electrode interface. The feedback loop control device measures the modulation frequency of ionization currents and provides a feedback adjustment of the tip-to-counter-electrode voltage to maintain ionization efficiency.

Abstract: A dispense system stores a scented material or materials and is provided with an electrical interface that is compatible with a hand-held device. The dispense system can be connected to the hand-held device and driven with the help of the hand-held device to dispense the scented material. The dispense system can be configured to store different scented materials that can be mixed to create different scents. Logic within the hand-held device supports the mixing and dispensing of the scented materials.

Abstract: The present invention relates to a microfluidic device for separating the components of a fluid sample. A cover plate is arranged over the first surface of a substrate, which, in combination with a microchannel formed in the first surface, defines a separation conduit for separating the components of the fluid sample. An inlet port in fluid communication with the separation conduit allows a mobile phase containing a gradient of a selected mobile-phase component to be introduced from an integrated gradient-generation means to the separation conduit. A method is also provided for separating the components of a fluid sample using a mobile phase containing a gradient of a selected mobile-phase component, wherein the gradient is generated within a small volume of mobile phase.

Abstract: A hybrid hard/soft microfluidic device is assembled by covalently bonding bard and soft materials. The channels are formed in a polyimide material, which is to be sandwiched between an integrated circuit and a glass cover. The glass covered is treated with an amino siloxane to form free amine groups. The polyimide is treated to form free carboxyl groups. The glass and polyimide are bonded through amidation. The remaining polyimide surface is treated with polyamines to form free amine groups, while silicon dioxide surfaces of the integrated surface are treated with isocyanate siloxane to form free isocyanate groups. The integrated circuit is then covalently bonded to the polyimide surface. The latter surface can be a thermoplastic coating that offers some compliance, more intimate contact, and more thorough bonding.

Abstract: The invention provides an evanescent wave sensor containing a porous nanostructure layer. In general, a subject sensor contains a transparent substrate and a porous nanostructure layer bound to a surface of the substrate. Also provided by he invention are methods of using the subject sensors, e.g., in analyte detection, as well as kits and systems that include the subject sensors.

Abstract: The present invention relates to a microfluidic device for separating the components of a fluid sample. A cover plate is arranged over the first surface of a substrate, which, in combination with a microchannel formed in the first surface, defines a separation conduit for separating the components of the fluid sample. An inlet port in fluid communication with the separation conduit allows a mobile phase containing a gradient of a selected mobile-phase component to be introduced from an integrated gradient-generation means to the separation conduit. A method is also provided for separating the components of a fluid sample using a mobile phase containing a gradient of a selected mobile-phase component, wherein the gradient is generated within a small volume of mobile phase.

Abstract: Provided are apparatuses and methods for introducing particles into a microdevice conduit. Also provided are microdevices containing a plurality of particles that occupy at least about 25 volume percent of a microconduit. In some instances, particles may controllably form a particle bridge in a bridging zone within a microdevice.

Abstract: The fluid flow rate within a microfluidic passageway of a microfabricated device is determined by measuring the time-of-flight of a heat pulse coupled into the fluid. Since the propagation velocity of the heat trace is generally slower than the mean flow rate of the flow, additional processing provides the appropriate scaling needed to obtain an accurate fluid flow rate measurement. The scaling factor is based on the geometry of the structure and the thermal properties of the fluid and the materials used for the device.

Abstract: An ion source for an analytical instrument is described. The ion source comprises a capillary tip and counter-electrode interface and a feedback loop control device connected to the capillary tip and counter-electrode interface. The feedback loop control device comprises a transimpedance amplifier, a DC de-coupler, a frequency to voltage converter, a controller, and a voltage-controlled high-voltage power supply that provides a tip to counter-electrode voltage to the capillary tip and counter-electrode interface. The feedback loop control device measures the modulation frequency of ionization currents and provides a feedback adjustment of the tip-to-counter-electrode voltage to maintain ionization efficiency.

Abstract: The subject invention includes constituent separation apparatuses that include a fluid pathway and a pair of spaced-apart electrodes positioned within the pathway for detecting current flow within a mobile phase present in the pathway. Coupled to the pair of spaced-apart electrodes is a mix ratio determinator for determining the mix ratio of the mobile phase from the detected current flow. Also provided are methods that include contacting a mobile phase with an apparatus for separating constituents of a mobile phase, detecting the current flow of the mobile phase when the mobile phase is in contact with the apparatus and determining the mix ratio of the mobile phase from the detected current flow. The mix ratio may be adjusted based on the determined mix ratio. Algorithms for practicing the subject methods are also provided on computer readable mediums. Systems and kits for practicing the subject methods are also provided.

Abstract: The fluid flow rate within a microfluidic passageway of a microfabricated device is determined by measuring the time-of-flight of a heat pulse coupled into the fluid. Since the propagation velocity of the heat trace is generally slower than the mean flow rate of the flow, additional processing provides the appropriate scaling needed to obtain an accurate fluid flow rate measurement. The scaling factor is based on the geometry of the structure and the thermal properties of the fluid and the materials used for the device.