Proceedings Article | 23 October 2006
Proc. SPIE. 6380, Smart Medical and Biomedical Sensor Technology IV
KEYWORDS: Statistical analysis, Capillaries, Spectroscopy, Surface enhanced Raman spectroscopy, Raman spectroscopy, Chemical analysis, Sol-gels, Urea, Human physiology, Mode conditioning cables
Extended weightlessness causes numerous deleterious changes in human physiology, including space motion sickness,
cephalad fluid shifts, reduced immune response, and breakdown of muscle tissue with subsequent loss of bone mass and
formation of renal stones. Furthermore, these physiological changes also influence the metabolism of drugs used by
astronauts to minimize these deleterious effects. Unfortunately, the changes in human physiology in space are also
reflected in drug metabolism, and current pre-flight analyses designed to set dosage are inadequate. Furthermore,
current earth-based analytical laboratory methods that employ liquid or gas chromatography for separation and
fluorescence or mass spectrometry for trace detection are labor intensive, slow, massive, and not cost-effective for
operation in space. In an effort to overcome these instrument limitations we have been developing a sampling device to
both separate these drugs and metabolites from urine, and generate surface-enhanced Raman (SER) spectra. The
detailed molecular vibrational information afforded by Raman scattering allows chemical identification, while the
surface-enhancement increases sensitivity by six or more orders of magnitude and allows detection of nanogram per
milliliter concentrations. Generally no more than 1 milliliter of sample is required and complete analysis can be
performed in 5 minutes using a portable, light-weight Raman spectrometer. Here we present the SER analysis of
several drugs used by astronauts measured in synthetic urine and reconstituted urine.
