Abstract: Droplets or plugs within multiphase microfluidic systems have rapidly gained interest as a way to manipulate samples and chemical reactions on the femtoliter to microliter scale. Chemical analysis of the plugs remains a challenge. It has been discovered that nanoliter plugs of sample separated by air or oil can be analyzed by electrospray ionization mass spectrometry when pumped directly into a fused silica nanospray emitter nozzle. Using leu-enkephalin in methanol and 1% acetic acid in water (50:50 v:v) as a model sample, we found carry-over between plugs was <0.1% and relative standard deviation of signal for a series of plugs was 3%. Detection limits were 1 nM. Sample analysis rates of 0.8 Hz were achieved by pumping 13 nL samples separated by 3 mm long air gaps in a 75 ?m inner diameter tube. Analysis rates were limited by the scan time of the ion trap mass spectrometer. The system provides a robust, rapid, and information-rich method for chemical analysis of sample in segmented flow systems.

Abstract: Droplets or plugs within multiphase microfluidic systems have rapidly gained interest as a way to manipulate samples and chemical reactions on the femtoliter to microliter scale. Chemical analysis of the plugs remains a challenge. It has been discovered that nanoliter plugs of sample separated by air or oil can be analyzed by electrospray ionization mass spectrometry when pumped directly into a fused silica nanospray emitter nozzle. Using leu-enkephalin in methanol and 1% acetic acid in water (50:50 v:v) as a model sample, we found carry-over between plugs was <0.1% and relative standard deviation of signal for a series of plugs was 3%. Detection limits were 1 nM. Sample analysis rates of 0.8 Hz were achieved by pumping 13 nL samples separated by 3 mm long air gaps in a 75 ?m inner diameter tube. Analysis rates were limited by the scan time of the ion trap mass spectrometer. The system provides a robust, rapid, and information-rich method for chemical analysis of sample in segmented flow systems.

Abstract: Systems and methods are provided for preparing samples for chromatographic separations and then chromatographically separating the prepared samples, preferably in a high-throughput fashion utilizing multiple parallel first (fluid) processing regions in fluid communication with multiple parallel second (fluid) processing regions wherein the each second processing region includes a chromatography column. One or more common fluid supplies may be utilized in each of the sample preparation and separation steps to minimize the number of requisite fluid connections and external components such as pumps, reservoirs, pulse dampers, flow controllers, and the like.

Abstract: Feedback control system for electrospray nozzle using optical system for monitoring and controlling dynamic or static morphology of the fluid exiting the electrospray nozzle.

Abstract: Systems and methods are provided for preparing samples for chromatographic separations and then chromatographically separating the prepared samples, preferably in a high-throughput fashion utilizing multiple parallel first (fluid) processing regions in fluid communication with multiple parallel second (fluid) processing regions wherein the each second processing region includes a chromatography column. One or more common fluid supplies may be utilized in each of the sample preparation and separation steps to minimize the number of requisite fluid connections and external components such as pumps, reservoirs, pulse dampers, flow controllers, and the like.

Abstract: Feedback control system for electrospray nozzle using optical system for monitoring and controlling dynamic or static morphology of the fluid exiting the electrospray nozzle.

Abstract: A feedback control system for an electrospray nozzle and counter-electrode, comprising a source of light which intersects, one or snore of the liquid cone, jet and plume of the fluid exiting the nozzle, one or more photo detectors to detect light patterns and generate photo-electronic signals in response thereto, an electronic detection and amplification system to convert the photo-electronic signals to electronic signals, a computer or micro-processor to interpret said electronic signals and a second computer or microprocessor to communicate with the first computer and generate a signal to a controller which adjusts the electric field surrounding the nozzle either by changing the distance between the nozzle and counter-electrode or changing the voltage of the nozzle or counter-electrode.

Abstract: Feedback control system for electrospray nozzle using optical system for monitoring and controlling dynamic or static morphology of the fluid exiting the electrospray nozzle.