A FLUOROMETRIC METHOD for the determination of pteroylglutamic acid (PGA) in nonbiologic material was reported by Alifrey et al (1). Freeman (2) adapted this method for the determination of amethopterm in plasma. Both procedures oxidized PGA or amethopterin with permanganate to yield a strongly fluorescent substance, 2-amino-4hydroxypteridine-6-carboxylic acid (3). The fluorescence due to the l...

This communication deals principally with the development of a method for the quantitative fluorometric measurement of the natural estrogens and introduces data on a similar test method for the quantitative determination of cholesterol. To achieve this goal, use has been made of the condensat.ion reaction of phenolic steroids with phthalic anhydride (1, 2). In view of the wide-spread interest i...

A. FULLY automated nlethod for the (leterinination of serum calcium which is accurate, reproducible, and relatively simple seemed desirable. The additioll of the fluorometer (1) to the modular system of the AutoAnalyzer* suggested the search for a fluorometric calcium procedure. Accordingly, several substances known to complex with calcium were obtained and their fluorescent emission spectra in...

A number of chemical methods have been described for the determination of riboflavin (1-13). These methods are in general limited in use because, when applied to certain products, either they are not specific for riboflavin or all the riboflavin present is not recovered (2). In most cases the authors of papers presenting riboflavin methods have indicated that the methods are of limited applicat...

A spectrophotofluorometric method is described for the determination of tyrosine in blood dried on filter paper discs. It has been found that by immersing the paper disc containing the dried blood in aqueoustrichioracetic acid, the blood proteins remain bound to the paper and the amino acid is eluted into the aqueousphase.This method of assay is based on the principle that tyrosine reacts with ...

We adapted the method of McCaman and Robins for fluorometry of phenylalanine to a microplate assay for routine phenylketonuria screening. Sensitivity is 15 mumol/L for the plasma assay and 30 mumol/L for the dried blood-spot assay, with CV less than 10% for both assays. Results for human plasma by microplate assay correlated well (r = 0.99) with results of amino acid analyzer determination of p...

A unique fluorometric and colorimetric “light-up” sensing strategy has been conceptualized to detect chloroform distinguish various volatile chlorinated solvents (VCSs) along with “dual-phase” security ink application.

The vitamin B 2 content of foods has historically been determined as total riboflavin (TRF), and the most common method of TRF analysis has been the AOAC standard fluorometric procedure. A modification of this method to permit the use of flow injection analysis (FIA) is reported here. A number of foods were analyzed and the results generally agreed with the published values. However, the standa...