Novel reagent for the determination of atmospheric isocyanate monomer concentrations

Abstract

A high-performance liquid chromatographic (HPLC) method for the determination of both aliphatic and aromatic isocyanates was first devised by Dunlap et al. using N-(4-nitrobenzyl)propylamine as the urea-forming reagent (nitro reagent). Subsequent w 0 r k ~9 ~ indicated serious disadvantages associated with the use of this reagent, including oxidation of the reagent both during and after sampling, deterioration of the HPLC column packing by excess of reagent in the samples and its unsuitability for sampling in a reducing atmosphere. These disadvantages appear to stem from the presence of the aromatic nitro group in this secondary amine.

Isocyanates

“…The '2-PP-reagent' showed excellent sensitivity and performance when used as the derivatizing agent for subsequent HPLC-evaluation [366] and was particularly successfully used in TDI analysis [367,368,369]. Detection is achieved using ultraviolet radiation as well.…”

“…Derivation of the isocyanate with ethylalcohol is another approach used to analyse diisocyanates with HPLC and UV -detection [366,370]. Because of the slow reaction of the alcohol, the method has its limitations.…”

Investigation of the competitive rate of derivatization of several secondary amines with phenylisocyanate (PHI), hexamethylene-1,6-diisocyanate (HDI), 4,4′-methylenebis(phenyl isocyanate) (MDI) and toluene diisocyanate (TDI) in liquid medium

“…Several derivatization agents were initially developed and/or evaluated. [21][22][23][24][25] However, they had limitations such as peak doubling, weak reactivity, poor stability, and in some cases they offer poor qualitative information or sensitivity. [23][24][25] Today, among the different reagents used, four analytical methods are currently under investigation as ISO International Standards, and they use four different reagents (Fig.…”

Detection of isocyanates and polychlorinated biphenyls using proton transfer reaction mass spectrometry

“…However, currently used analytical techniques have their limitations. The most commonly used analytical methods for the detection of isocyanates in air are based on ultraviolet or visible absorption spectrometry . Isocyanates in air can also be analyzed by liquid chromatography with fluorescence detection using N ‐methyl‐1‐naphthalenemethylamine (MNMA) as a fluorescence active reagent .…”

“…The most commonly used analytical methods for the detection of isocyanates in air are based on ultraviolet or visible absorption spectrometry. [7][8][9][10][11][12][13][14][15] Isocyanates in air can also be analyzed by liquid chromatography with fluorescence detection using N-methyl-1-naphthalenemethylamine (MNMA) as a fluorescence active reagent. [3] The detection techniques based on fluorescence are extremely sensitive but they may suffer from problems such as quenching, bubbles in the sample and variation in pH values.…”