Electrostatic sprayer

Table III. Applicator Exposure Using Conventional and Electrostatic Sprayers...

Knowledge of the fact that the fundamental operation of electrostatic sprayers involves an electrochemical process pre-dates their use as an ion source in ES-MS. The circuit diagrams for electrostatic sprayers that are found in the literature from the early 1900s are... 

This means that charge cannot flow through these circuit junctions except via heterogeneous electron transfer chemistry. Heterogeneous electron transfer chemistry is electrochemistry. Thus, electrochemistry is inherent to the operation of the electrostatic sprayer used in ES-MS. 

Figure 5.21 Photograph of jets formed from an oil-ethanol mixture in a laboratory scale model of an electrostatic paint sprayer. Reproduced with permission from Hines, /. App. Phys. 37, 2730 (1966). Copyright (1966) American Institute of Physics.

A specific example of the continuity between applied and fundamental research, of direct relevance to the subject of this book (see Chapter 5), is provided by the direct line of development starting from an electrostatic paint sprayer designed for industrial use, through attempts by materials scientists to prepare single molecules of synthetic polymers in the gas phase to enable fundamental studies, to the eventual award of a Nobel Prize to John B. Fenn for the invention of electrospray ionization mass spectrometry and its application to biochemistry and molecular biology. 

Protection by limitation of energy is in subsections 411-04 and 471-03. The intention is not to prevent the shock sensation but to limit the shock current and/or its duration so as to avoid injury to persons and animals. Common examples of equipment complying with this requirement are electric fence energisers, electrostatic paint and powder sprayers, and tungsten inert gas (TIG) welding electrodes. 

Analyte ions can also be efficiently generated when sample vapor or finely dispersed sample droplets transported by a carrier gas stream are admixed to the expanding electrospray plume. This technique, simple yet effective, has been introduced as extractive electrospray ionization (EESI) [37]. It utilizes two separate sprayers, one conventional ESI sprayer to provide the electrostatically charged mist and another to supply the sample vapor or mist (Fig. 13.13). While this approach is suggested for API interfaces with the heated transfer capillary design, the sample carrier stream may alternatively be passed into the desolvation gas of interfaces employing the heated curtain gas design (Fig. 13.14) [6,38]. 

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