Accession Number : ADA310673

Title :   Feasibility of an in Situ Flow Cytometer.

Descriptive Note : Final rept. 1 Jul 93-31 Dec 94,

Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF BIOLOGY

Personal Author(s) : Olson, Robert J. ; Williams, Albert J., III

PDF Url : ADA310673

Report Date : DEC 1994

Pagination or Media Count : 8

Abstract : Our objective was to design an in situ instrument to analyze the optical properties of individual suspended particles, which are important to ocean geochemistry, optics, and biology. The approach arrived at is that of a flow cytometer modified to facilitate in situ unattended operation (use of a battery-powered solid state laser for fluorescence excitation, and of a neural network to carry out real-time data analysis). To increase reliability we use a simple ducted flow of seawater through the instrument rather than injection of seawater into the center of a particle-free fluid stream as in conventional flow cytometers. Simple ducted flow, which does not mechanically confine sample particles to a path through the central region of the focussed laser beam, requires a means of discriminating particles with acceptable trajectories from those which pass through the less-intense edges of the beam and thus give inaccurate signals. We have demonstrated that two orthogonal infrared diode laser beams can be used for this purpose: the beams can be arranged so that particles passing through both infrared beams must also pass through the center of the fluorescence excitation beam, and signals from only these particles will be collected. The instrument is now in development.

Descriptors :   *OCEANOGRAPHIC EQUIPMENT, *DIODE LASERS, LIGHT SCATTERING, OPTICAL PROPERTIES, WATER FLOW, NEURAL NETS, FLUORESCENCE, REAL TIME, LASER BEAMS, OCEANOGRAPHIC DATA, INFRARED LASERS, SUSPENDED SEDIMENTS, FEASIBILITY STUDIES, INFRARED DETECTORS, SEA WATER, GEOCHEMISTRY, PHYTOPLANKTON.

Subject Categories : Physical and Dynamic Oceanography
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE