Isocyanates fluorescence determination

AEOs have been analysed by HPLC and UV or fluorescence detection after suitable derivatisation. The derivatising agents proposed so far are phenyl isocyanate [80,81], 1-anthroylnitrile [82], 3,5-dinitro-benzoyl chloride [83], naphthyl isocyanate [84] and naphthoyl chloride [84], However, the lack of fluorescence activity and the need for synthesis through a multistep reaction for some derivatising agents limits their application in a real-world analysis. In fact, only a few of them were applied in the determination of AEOs in environmental samples. Zanette et al. [84] developed derivatisation and separation... 

Kormos LH, Sandridge RL, Keller J. 1981. Determination of isocyanates in air by liquid chromatography with fluorescence detection. Anal chem 53(7) 1122-1125. 

Levine SP, Hoggatt JH, Chladek E, et al. 1979. Determination of aliphatic isocyanates in air by a liquid chromatographic-fluorescence technique. Anal Chem 51(8) 1106-1109. 

Wu WS, Stoyanoff RE, Szklar RS, et al. 1990. Application of Tryptamine as a derivatising agent for airborne Isocyanate determination. Part 3 evaluation of total isocyanates analysis by high-performanee liquid chromatography with fluorescence and amperometric deteetion. Analyst 115 801-807. 

A New Fluorescence Procedure for the Determination of Methyl Isocyanate in the Occupational Environment... 

Analysis of the enantiomeric ratios of several p-blocking drugs (l-aryloxy-3-isopropylamino-2-propanol derivatives) is carried out by HPLC with UV or fluorescence detection after derivatization with (R)-NEI or (i )-(+)-l-(l-phenyl)ethyl isocyanate (in a reversed-phase system), or (S)-NEI (on silica gel) only the amine function of the drugs reacts with the NEI the hydroxy group does not. Similar schemes for HPLC determination of enantiomeric purity of tetrahydrofolate derivatives and of fluoxetine are also reported. 

Aromatic amines undergo condensation with fluorescamine (93), presumably according to equation 7, to yield fluorescent products (94). The process was applied to derivatize PAA mixtures prior to determination by MEKC with FLD (Section IV.C)189,190. This derivatizing procedure was used for detection of unreacted isocyanate residues in the... 

Sango, C. and Zimerson, E., A new reagent for determination of isocyanates in working atmospheres by HPLC using UV or fluorescence detection, J. Liq. Chromatogr., 3, 971-990, 1980. 

Isocyanates are derivatised with tryptamine (27) and determined with a dual detection system based on fluorescence and amperometric oxidation Tryptamine and N-co-methyltryptamine (28) were found to be the most promising scavenging reagents for airborne organic isocyanates, before analysis by HPLC with reverse-phase columns and UV detection A personal sampler for airborne isocyanates in workplaces was developed based on 27. ... 

Environmental analyses often involve the determination of low concentrations (viz., a few nanograms or picograms per milliliter) that require the sensitivity of fluorescence analysis. Most environmental applications of fluorimetric methods involving air, water, or soil pollution are concerned with polycyclic aromatic compounds, which feature high fluorescence quantum yields. However, in recent years, the scope of fluorimetric techniques has been successfully extended to other major nonfluorescent pollutants such as isocyanates after conversion into fluorescent species. But fluorescence detection and determination of pollutants is still confronted with problems arising from a lack of selectivity. Such problems are currently... 

LC methods using fluorescence detection, like most reported LC methods for the determination of isocyanates, have mainly been applied to monomer diisocyanates. In as much as they provide a different detector response for each isocyanate derivative, they require individual isocyanate standards for quantification. As a result, their application to polymeric forms is subject to some drawbacks shared by determinations of polymers using chromatographic procedures, viz., the lack of appropriate standard materials. In fact, such important data as pvu ity, the precise identity of the polymeric components, and the nature of the additives used in the isocyanate polymers available for calibration are often lacking. 

X-ray fluorescence is the most convenient technique to determine total chlorine and bromine content. Bromine may be introduced as an impurity in the phosgene used in isocyanate synthesis. 

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