Randy R Russell

US Patent:

59255722, Jul 20, 1999

Filed:

Aug 6, 1997

Appl. No.:

8/907324

Inventors:

Robert H. Byrne - St. Petersburg FL
Robert D. Waterbury - Palm Harbor FL
John J. Kelly - Clearwater FL
Bram Leader - Clearwater FL
Randy Russell - Safety Harbor FL
Charles W. Jones - Seminole FL
Joseph R. Kolesar - Pinellas Park FL
Sean McElligott - Bryn Mawr PA

Assignee:

University of South Florida - Tampa FL

International Classification:

G01N 2180
G01N 2100

US Classification:

436163

Abstract:

A pH sensor based upon spectrophotometric techniques has been developed for in situ analysis of an aqueous medium, e. g. , surface seawater. This sensor utilizes a spectrophotometric pH indicator (Thymol Blue), which has been calibrated for use in seawater as a function of temperature and salinity. Shipboard spectrophotometric pH analyses routinely demonstrate a precision on the order of. +-. 0004 pH units. In situ analysis of seawater pH has demonstrated a precision on the order of. +-. 001 and an accuracy, using shipboard measurements as a standard, on the order of. +-. 01. The sensor is a self-contained system that pumps seawater, meters in indicator, and spectrophotometrically determines indicator absorbance cells, each with three wavelength channels, to obtain the spectrophotometric absorbance. The sensor system, rated for depths up to 500 m, provides pH, conductivity, and temperature and can be operated via computer or in a standalone mode with internal data storage. The sensor utilizes less than 12 watts of power and is packaged in an aluminum housing.