Identification of carbonyl compounds in environmental samples

Abstract

Carbonyl compounds play an important role in many environmental oxidation processes, but the identification of unknown carbonyl compounds can be difficult using existing techniques. We have developed an approach using derivatization with 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) followed by gas chromatography/mass spectrometry (GC/MS) analysis for the identification of unknown carbonyl compounds. Electron ionization, electron-capture negative chemical ionization, and positive chemical ionization mass spectrometry have all been examined using model compounds. Methods for identifying molecular weight are described, as well as methods for differentiating between different types of carbonyl compounds. GC/MS analysis of compounds containing carboxylic acid or hydroxyl groups in addition to the carbonyl group can be conducted by using PFBHA derivatization in conjugation with methylation and silylation. Electron ionization mass spectrometric analysis of the derivatives will usually provide for adequate molecular weight and structural information. The methods developed are demonstrated for three different types of samples.

Detection limits of electron and electron capture negative ionization-mass spectrometry for aldehydes derivatized with o-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride

“…A ldehydes, as products of the lipid peroxidation reactions and various atmospheric processes, are often detected in biological and environmental matrices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Derivatization of aldehydes is typically employed before the analysis to improve chromatographic separation and detection limits [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Quantification of Carbonyl Compounds Generated from Ozone-Based Food Colorants Decomposition Using On-Fiber Derivatization-SPME-GC-MS

“…The molar concentration of PFBHA solution was 10 times higher than that of the carbonyl compound to ensure a quantitative reaction, and the reaction was carried out in the dark at room temperature for at least 2 h [12]. The solution was then quantitatively introduced into the GC-MS system by direct injection.…”

“…Carbonyl compounds have also been found as major byproducts in other ozonolysis applications, such as treatment of paper pulp and water [12] and in the oxidative disinfection of drinking water [13]. Although most of these aldehydes are of negligible or minor concern, toxicity can arise during metabolism.…”

“…Carbonyl compounds are also reactive outside of the body, and are typically derivatized for sampling [12].…”

Determinação de compostos carbonilados e carboxilados em derivados de petróleo

“…24 Muitos dos métodos até então desenvolvidos propõem-se a avaliar a contaminação de produtos da 2ª geração (polietileno (PE), polipropileno (PP) e policloreto de vinila (PVC)), determinando as concentrações dos compostos orgânicos formados durante a extrusão, através de sistema analítico acoplado a técnicas de dessorção térmica e CG-EM com deslocamento simultâneo. 9,25 Outros estudos utilizando a técnica de cromatografia líquida de alta eficiência (CLAE) e derivatização com 2,4-dinitrofenilidrazina têm sido desenvolvidos, visando determinar concentrações de compostos carbonílicos presentes no ar atmosférico como produtos intermediários de reações fotoquímicas de emissões veiculares, especialmente formaldeído e acetaldeído, que são os compostos carbonílicos mais abundantes em atmosferas urbanas. [6][7][8]26,27 Especificamente para determinação de formaldeído, têm sido utilizados métodos espectrofotométricos e espectrofluorimétricos, após a amostragem com cartuchos de sílica impregnados com 4-Aminopent-3-en-2-one (Fluoral P), 28 no caso da fase gasosa, Cp-ciclopentadienil ou através de injeção em fluxo associada à espectrofotometria em fase sólida, no caso de álcool combustível.…”