Droplet electrospray device

The term nebulizer is used generally as a description for any spraying device, such as the hair spray mentioned above. It is normally applied to any means of forming an aerosol spray in which a volume of liquid is broken into a mist of vapor and small droplets and possibly even solid matter. There is a variety of nebulizer designs for transporting a solution of analyte in droplet form to a plasma torch in ICP/MS and to the inlet/ionization sources used in electrospray and mass spectrometry (ES/MS) and atmospheric-pressure chemical ionization and mass spectrometry (APCI/MS). 

Nebulizers are used to introduce analyte solutions as an aerosol spray into a mass spectrometer. For use with plasma torches, it is necessary to produce a fine spray and to remove as much solvent as possible before the aerosol reaches the flame of the torch. Various designs of nebulizer are available, but most work on the principle of interacting gas and liquid streams or the use of ultrasonic devices to cause droplet formation. For nebulization applications in thermospray, APCI, and electrospray, see Chapters 8 and 11. 

Electrospray a solution of the sample in a solvent is pumped into the source through a capillary submitted to an electric field of several kilovolts per centimetre. This produces droplets and solvated ions in the gas phase. The solvated ions pass through a desolvation device under vacuum and are injected into the analyser. Electrospray produces multiply charged ions from large molecules. 

Once the section is mounted to the sample plate with the desired orientation, matrix solution is deposited on the tissue surface by electrospray deposition, aero spray, or using robotics to deposit small matrix droplets across the tissue surface before MALDI analysis [13]. The most common and least expensive devices available for applying matrix are hand-held aerosol sprayers or air brushes. The main advantage of these devices is that, with careful application, a dispersion of very small droplets... 

We used extensively studied amphiphiles for the emulsion formation in the first step. The oil soluble surfactants Span 80 and Brij 72 are well-known to stabilize emulsions, and they can also form niosomes [8-10]. Furthermore we utilized the natural product lecithine, which is also oil-soluble, and an important component of biological membranes [11], The emulsions were generated with established methods like sonication with ultrasound, applying electrosprays or using microemulsion formations [12-14], In addition, we constracted different microfluidic devices to produce small aqueous droplets in oil. Similar techniques were often used for the production of double emulsions [15, 16]. During droplet formation in the organic phase, a single layer of surfactants adsorbed at the surface of these particles. This thin film of surface-active compounds stabihzed the emulsion droplets and lowered the surface tension [17], A second surfactant film was also formed at the plane oil-water interface of the reaction vessel (Fig. 1). 

Considering the requirements for charge balance in such a continuous electric current device and the fact that only electrons can flow through the metal wire supplying the electric potential to the electrodes, one comes to the conclusion that the electrophoretic charge separation mechanism [of droplet charging and formation] requires that the [positive-ion] electrospray process should involve an electrochemical conversion of ions to electrons [within the metal ES capillary[. 

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