Abstract: One embodiment of a humidifier designed to supplement humidity for the purpose of maintaining the moisture content of a wooden instrument such as a guitar. The humidifier comprises of an absorbent material, contained within an expandable outer shell, sealed at both ends. The shell is made from a non-permeable material but is constructed to be permeable. The humidifier is hydrated by submerging it in water, resulting in the absorption of liquid, causing expansion of the absorbent core and consequently expansion of the outer shell. Once hydrated, the outer shell is dried, and then, in the case of a hollow bodied instrument, is placed inside the body, or alternatively, and in the case of a solid bodied instrument, is placed in proximity to the instrument in a case or other enclosure. The shell allows the efficient egress of water vapor while isolating the instrument from liquid sequestered by the absorbent within.

Abstract: A soft chemical ionization source can be small, require low power, reliably produce different ions depending on the operating conditions and configuration, and produce ions that ionize many sample chemicals in different phases in air, or solutions, or on surfaces. In one embodiment, an ionization source is comprised of a housing having a center post extending therefrom, a plurality of needles extending from the housing, and a counterelectrode extending around the housing. The plurality of needles and the counterelectrode are each coupled to an electrical supply. The center post and the plurality of needles extend through the counterelectrode. A voltage applied to the plurality of needles and the counterelectrode forms a gas discharge. By changing the dimensional or electrical characteristics of the ionization source elements, singularly, or relative to other sources in an array, the types, ratios among, and quantities of reagent ions can be changed and controlled.