Publications by authors named "Gary D Rayson"

Plants offer the potential for selective removal and sequestration of toxic heavy metals from contaminated soil. Phytoextraction of metal ions involve their transport through the plant's root system and into its shoots and leaves. This study investigates the thermodynamics of Eu(III) ion chemical interactions with Datura innoxia plant root materials under solution conditions of pH 4.

View Article and Find Full Text PDF

The binding of Eu(III) to a biosorbent derived from cultured cells of the plant Datura innoxia, have been investigated through elucidation of apparent affinity constants associated with different chemical environments present on the cell wall. Adsorption isotherms for separate types of binding sites were generated using metal ion luminescence measurements. Application of regularized regression analysis to these isotherm data for four chemically distinguishable sites revealed the presence of sites exhibiting both low (mean log K(app)=-0.

View Article and Find Full Text PDF

Fluorescent contaminants have been observed when stock solutions of phosphate buffered saline solutions at each of three pH values (2.2, 7.5, and 12.

View Article and Find Full Text PDF

A portable luminescence spectrofluorometer weighing only 1.5 kg that uses multiple light emitting diodes (LEDs) as excitation sources was developed and evaluated. Excitation using a sequence of seven individual broad-band LED emission sources enabled the generation of excitation-emission spectra using a light weight (<1.

View Article and Find Full Text PDF

The ability to distinguish among diets fed to Damascus goats using excitation-emission luminescence spectra was investigated. These diets consisted of Medicago sativa L. (alfalfa), Trifolium spp.

View Article and Find Full Text PDF

The investigation of the competitive binding of metal ions to a biogenic material comprised of organic peat immobilized in a polysilicate matrix was undertaken. This material was packed into 5.0mL bed-volume columns using 40-60mesh size particles.

View Article and Find Full Text PDF

Photoluminescence of plant extract solutions has been investigated for discrimination of plant life forms (grasses, forbs, and shrubs) using principal component analysis (PCA). Clippings from each of six plant species representing three different plant life forms potentially found in the diets of free-ranging herbivores in the Chihuahuan Desert of North America were investigated for possible discernment. These plants included Sporobolus flexuosus (mesa dropseed, a grass), Pleuraphis mutica (tobosa, a grass), Dimorphocarpa wislizenii (spectacle pod, a forb), Sphaeralcea incana (pale globemallow, a forb), Flourensia cernua leaves (tarbush, a shrub), and Atriplex canescens leaves and stems (fourwing saltbush, a shrub).

View Article and Find Full Text PDF

An on-line detection scheme has been developed for the determination of metal ion affinities for binding to a plant-based substrate. This involves monitoring the effluent of a column packed with cell-wall fragments from the plant Datura innoxia for 27 different elements simultaneously by coupling the column to an ICP emission spectrometer. Previously accepted procedures for removing native metal ions from biological materials by washing the material with a pH 2 solution were found to be insufficient for this material.

View Article and Find Full Text PDF