title: Evaluation of a hyperbaric system to be used in conjunction with a fluorometer.
abstract: A high-pressure chamber that can be used inside the sample chamber of a spectrofluorometer is described and some performance characteristics are presented. The chamber body, constructed of 316 stainless steel, is temperature regulated using resistive heating elements and a microprocessor-based proportional integral derivative controller. The chamber holds a standard 1-cm2 cuvette that indexes with an electromagnetic stirrer. Injection of different solutions into the closed and pressurized (6.8 MPa) vessel is accomplished by computer-controlled, low-volume solenoids attached to separate microliter injection ports. Repetitive injections of fluids down to a volume of 7 microliters are possible in the pressurized chamber. Temperature stability of the chamber is +/- 0.2 degrees C at atmospheric or elevated pressure. However, during the initial phase (first 3 min) of pressurization, at a compression rate of 0.62 MPa/min, a 0.23 degrees C/min increase in temperature occurs. The chamber windows depress the relative intensity of the emitted light by approximately 20% for visible light and 40% for near UV; however, total sensitivity of the system is sufficient to accomplish most determinations while maintaining a good signal-to-noise ratio. This system can be used to evaluate the response of several molecular and cellular events during compression and at depth with the use of various fluorometric probes.
authors.affiliation: Dysbaric Diseases and Treatment, Naval Medical Research Institute, Bethesda, Maryland 20889-5055.
authors.forename: J S
authors.initials: JS
authors.lastname: Colton
authors.forename: Y
authors.initials: Y
authors.lastname: Grossman
authors.forename: K
authors.initials: K
authors.lastname: Miller
authors.forename: S L
authors.initials: SL
authors.lastname: Pocotte
mesh_terms: D001273:Atmosphere Exposure Chambers; D004867:Equipment Design; D005470:Fluorometry / Q000379:methods*