Umbelliferone (7-hydroxycoumarin) and its conjugates appear to be metabolites ofcoumarin in the rabbit (Mead, Smith & Williams, 1955). It was observed that, although umbelliferone fluoresced strongly in ultraviolet light at pH 9-10, its conjugates showed little or no fluorescence. The glucuronide and ethereal sulphate of umbelliferone were therefore made and the former was found to be practical...

Mushrooms contain high amounts of substances like chitin and glucans, which can be used for medical purposes and nutrient matter. Therefore, an easy quantification method for chitin and for glucans, with high precision, is a matter of particular importance. For this purpose, we developed an easy and unique photometric method for the determination of -1,3-1,6 glucans in mushrooms. This method i...

The determination of radium and/or uranium concentrations in natural waters is useful in a wide range of environmental studies. In this work, a low-background liquid scintillation system (Wallac, Quantulus 1220) was used to determine simultaneously 226Ra and uranium (total) activities in natural water samples. Sample preparation involved filtration and 1 : 10 concentration by evaporation. Then,...

A simple, direct, sensitive, and selective stopped-flow method for the fluorimetric determination of uric acid in serum and urine samples is described. The variation of fluorescence intensity during the reaction between uric acid and 1,1,3-tricyano-2-amino-1-propene (triap) in the presence of hydrogen peroxide is monitored. For these kinetic measurements peroxide is monitored. For these kinetic...

HE INCREASING USE of fluorimetry in routine analysis is reflected in a variety of commercially available instruments which, in many instances, are either prohibitive to the average laboratory due to high cost or lack proper sensitivity. Unlike the Beckman DU spectrophotometer, its clinical counterpart, known as Model B, is not provided with a standard fluorimetric attachment. The versatility of...

A portable instrument for oxygen determination, based on the quenching of phosphorescent octaethylporphyrin by gaseous O(2), has been developed using the fluorimetric paired emitter-detector diode technique (FPEDD). The instrument configuration consists of two light-emitting diodes (LEDs) facing each other, with an interchangeable support containing a phosphorescent membrane in between, in whic...