Abstract: An electrokinetically pumped sheath flow nanospray interface for capillary electrophoresis coupled to negative mode electrospray mass spectrometer is described. At this interface, application of an electric field generates electro-osmotic flow at the interior of a glass emitter having an orifice. Electroosmotic flow pumps liquid around the distal tip of the separation capillary, ensheathing analyte into the electrospray electrolyte. In negative ion mode, negative potential applied to an untreated emitter drives sheath flow away from the emitter orifice, decreasing the stability and efficiency of the spray. In contrast, when the interior of the electrospray emitter is grafted with aminoalkylsilanes, the amines have a positive charge, which reverses electroosmosis and generates stable sheath flow to the emitter orifice under negative potential. Limits of detection were about 150 to 900 attomoles injected.

Abstract: An electrokinetically pumped sheath flow nanospray interface for capillary electrophoresis coupled to negative mode electrospray mass spectrometer is described. At this interface, application of an electric field generates electro-osmotic flow at the interior of a glass emitter having an orifice. Electroosmotic flow pumps liquid around the distal tip of the separation capillary, ensheathing analyte into the electrospray electrolyte. In negative ion mode, negative potential applied to an untreated emitter drives sheath flow away from the emitter orifice, decreasing the stability and efficiency of the spray. In contrast, when the interior of the electrospray emitter is grafted with aminoalkylsilanes, the amines have a positive charge, which reverses electroosmosis and generates stable sheath flow to the emitter orifice under negative potential. Limits of detection were about 150 to 900 attomoles injected.

Abstract: The combined capillary electrophoresis electrospray mass spectrometry apparatus has a circuit to handle excess current allows separations under a wide range of electrophoretic conditions. The apparatus includes an electrospray with an emitter and an electrospray interface connected with a separation capillary configured to transport a sample with an injection end and a distal end. The injection end of the separation capillary is inserted into a reservoir containing a background electrolyte and the distal end is threaded within the electrospray interface and sized and shaped to mate with the electrospray interface. A power supply is electrically connected to the injection end and an amplifier at least one first diode positioned between the amplifier and the distal end allows current to flow to the distal end only. A second diode positioned between the distal end and a ground configured to allow current flow to the ground.

Abstract: A method and system is provided for making store sales at a location remote from a sales counter in the store. A mobile computer device is used as a point-of-sale device to scan a product bar code identifier, to display product information associated with the product identifier, to input a quantity of items to be purchased by a customer and to select a payment type for purchasing the items. The device can communicate wirelessly with a database of product, inventory, sales and customer information and can automatically select the type of wireless connection to use. The device includes a card reader to read information from a payment card and a PIN entry pad for entering a PIN when the payment card has a debit capability. The device includes a PIN pad test program to determine whether the PIN entry pad is defective.