Determination of free formaldehyde in foundry resins as its 2,4-dinitrophenylhydrazone by liquid chromatography

Abstract

Formaldehyde is a toxic component that is present in foundry resins. Its quantification is important to the characterisation of the resin (kind and degradation) as well as for the evaluation of free contaminants present in wastes generated by the foundry industry. The complexity of the matrices considered suggests the need for separative techniques. The method developed for the identification and quantification of formaldehyde in foundry resins is based on the determination of free carbonyl compounds by derivatization with 2,4-dinitrophenylhydrazine (DNPH), being adapted to the considered matrices using liquid chromatography (LC) with UV detection. Formaldehyde determinations in several foundry resins gave precise results. Mean recovery and R.S.D. were, respectively, >95 and 5%. Analyses by the hydroxylamine reference method gave comparable results. Results showed that hydroxylamine reference method is applicable just for a specific kind of resin, while the developed method has good performance for all studied resins.

Determination of formaldehyde in shiitake mushroom by ionic liquid-based liquid-phase microextraction coupled with liquid chromatography

“…Results shown in Fig. 2 demonstrated that the influence of pH was significant and the highest peak area was obtained at pH 3.6, which was not in agreement with those reported elsewhere [11]. In the following studies, a pH 3.6 HOAc-NaOAc buffer was selected as optimum.…”

“…In recent years, chromatographic methods including GC [6,7] and HPLC [9][10][11] have been the most frequently reported one for the determination of formaldehyde. The most commonly used sample preparation procedure for chromatographic determination of formaldehyde is based on its reaction with 2,4-dinitrophenylhydrazine (DNPH) to form the corresponding hydrazone (DNPHo), which is extracted by liquid-liquid extraction [12], solid-phase extraction [11] or solid-phase microextraction [7,8]. Although the DNPH derivation method has relatively good selectivity, extraction is commonly used as sample clean-up procedure before chromatographic separation [14].…”

The constraints of transition metal substitutions (Ti, Cr, Mn, Co and Ni) in magnetite on its catalytic activity in heterogeneous Fenton and UV/Fenton reaction: From the perspective of hydroxyl radical generation

“…• OH radicals generated in heterogeneous Fenton and UV/Fenton processes were trapped with dimethyl sulfoxide (DMSO) to produce formaldehyde quantitatively [14,26,27], then reacted with 2,4-dinitrophenylhydrazine (DNPH) to form hydrazone (DNPHo) and were analyzed by high performance liquid chromatography (HPLC) [28]. The details of analysis procedure are provided in Text A.2 in Supplementary material.…”

Efeito da presença e concentração de compostos carbonílicos na qualidade de vinhos

“…É o aldeído mais simples, mas provavelmente o mais estudado devido à sua freqüente incidência na atmosfera e hidrosfera, provocando irritação nos olhos e no trato respiratório, náuseas, dor de cabeça, cansaço e sede 29,30 .…”

“…29), nos vinhos tintos o acetaldeído também pode ser produzido através da oxidação do etanol, provocada pelo peróxido de hidrogênio formado na reação entre os polifenóis presentes no mosto das uvas tintas e o oxigênio que se difunde através da madeira do barril e é dissolvido lentamente.…”