A Spectrophotometric Analyzer for Aqueous Samples in Microgravity

Format:

Conference/Event

Author/Creator:

Burchfield, David, author.

Conference Name:

International Conference On Environmental Systems (1999-07-12 : Denver, Colorado, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 1999

Summary:

The development of a spectrophotometric analyzer for use on water samples in microgravity environments is discussed. The instrument is constructed around a commercial spectrophotometer, the Hewlett-Packard HP8453, with a separate turbidimetric analyzer, here a modified Hach 2100P ratio turbidimeter. Flow-through sample cells were constructed for each instrument to support microgravity use and sample deaeration. Spectrophotometric analyses on aqueous samples on orbit are sensitive to the presence of undissolved gases in the samples. In a micro-g environment, free gas in samples can and does remain suspended, clouding the mixture and interfering with spectral optical density measurements. This paper discusses the design of a spectrophotometric analyzer, with particular emphasis on the merits of two approaches to eliminating free gas interferences in on-orbit water analyses: hyperbaric gas redissolution and deaeration across a hydrophobic membrane. Both techniques mitigate gas loads effectively - membrane removal uses a minimum of sample and time, hyperbaric redissolution takes more time, but provides capability to handle bubbles should gas get introduced into or otherwise evolve in the analytical system

Notes:

Vendor supplied data

Publisher Number:

1999-01-2032

Access Restriction:

Restricted for use by site license