salicylates and 6-carboxyfluorescein

A double-receptor sandwich supramolecule method for the separation and determination of trace uranium was proposed in this paper. One receptor is a salophen which can react with uranyl to form a uranyl-salophen complex, and another receptor is an oligonucleotide which can bind uranyl to form oligonucleotide-uranyl-salophen supramolecule. The salophen was immobilized on the surface of silica gel particles and used as the solid phase receptor for separating uranium from solution. The oligonucleotide was labeled with a fluorescent group and used as the labeled receptor for quantitatively analyzing uranium. In the procedure of separation and determination, uranyl ion was first combined with the solid phase receptor and then conjugated with the labeled receptor to form the sandwich-type supramolecule. The labeled receptor in the sandwich supramolecule was then eluted and determined by fluorescence analysis. The experimental results demonstrate that this method has a number of advantages such as high selectivity, excellent pre-concentration capability, high sensitivity, good stability and low cost. Under optimal conditions, the linear range for the detection of uranium is 0.5-30.0 ng mL(-1) with a detection limit of 0.2 ng mL(-1). The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-105.5%.

Topics: Fluoresceins; Fluorescent Dyes; Limit of Detection; Oligonucleotides; Organometallic Compounds; Salicylates; Sensitivity and Specificity; Silica Gel; Uranium

The effects of sodium salicylate on the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), 2-hydroxyoctadecanoic acid, 9-anthroate (2-AS), 12-hydroxyoctadecanoic acid, 9-anthroate (12-AS), 8-anilino-1-naphthalenesulfonic acid (ANS) and 2',4',5',7'-tetrabromo-5-maleimidofluorescein, disodium salt (EM), with which rat small intestinal brush border membrane vesicles were labeled, were examined. Salicylate ion decreased the fluorescence polarization of ANS and EM in these vesicles, however, it had no influence on the fluorescence polarization of DPH, 2-AS and 12-AS-labeled vesicles. It also released trapped 6-carboxyfluorescein (3',6'-dihydroxy-3-oxospiro-[phthalan-1,9'-xanthene]-6-carbo xylic acid) (CF) from the vesicles, but caused no leakage of trapped CF from liposomes. These results indicate that salicylate ion increases the plasma membrane permeability by effecting the plasma membrane proteins rather than directly interacting with the membrane lipids. The action of salicylate ion on these vesicles could possibly promote nonabsorbable drug absorption in vivo.

Topics: Animals; Cell Membrane Permeability; Fluoresceins; In Vitro Techniques; Intestinal Absorption; Intestine, Small; Male; Microvilli; Phospholipids; Rats; Rats, Inbred Strains; Salicylates; Salicylic Acid; Spectrometry, Fluorescence; Time Factors