Determination of low‐aliphatic aldehydes indoors by micellar electrokinetic chromatography using sample dissolution manipulation for signal enhancement

Abstract

This work describes a novel approach for the analysis of selected aldehydes (formaldehyde, acetaldehyde, propionaldehyde, and acrolein) and acetone in environmental samples using micellar electrokinetic chromatography (MEKC). The method is based on the reaction of carbonyl compounds with 3-methyl-2-benzothiazoline hydrazone (MBTH) that gives an azine intermediate with maximum absorbance at 216 nm. A systematic evaluation of sample dissolution medium was conducted as a means to enhancing sensitivity. In the best condition, samples were dissolved in 0.030 mol.L(-1) tetraborate solution. This condition presented enhancement factors in the range of 35-54 for the aldehydes under investigation, computed as the improvement of the concentration limits of detection (LODs) with reference to the sample dissolved in pure water. The running buffer was 0.020 mol.L(-1) tetraborate, pH 9.3, containing 0.050 mol.L(-1) sodium dodecyly sulfate (SDS). The overall methodology presented several advantages over established methods for aldehydes. Worthy mentioning that MBTH is available in high purity degree, dispensing laborious reagent purification procedures. A few method validation parameters were determined revealing good migration time repeatability (< 2.5% coefficient of variation, CV) and area repeatability (< 4% CV), excellent linearity (20-120 micro g/L, r > 0.995) and adequate sensitivity for environmental applications. The LODs with respect to each single aldehyde were in the range of 0.54-4.0 micro g.L(-1) and 11 micro g.L(-1) for acetone. The methodology was applied to the determination of aldehydes indoors. Samples were collected in an impinger flask containing 0.05% MBTH solution, at a flow rate of 0.80 L.min(-1), during 2.5 h, at different times during the day. The most abundant carbonyls in the samples were acetone, followed by formaldehyde and acetaldehyde, with estimate peak concentrations of 452, 5.2 and 2.2 ppbv, respectively.

High‐performance liquid chromatography and capillary electrophoresis: Methodological challenges for the determination of biologically relevant low‐aliphatic aldehydes in human saliva

“…From among the series of reagents described in the literature [10,20], DNPH was preferred over others for derivatizing the low-aliphatic aldehydes formaldehyde, acetaldehyde and acrolein (according to the scheme reported in Fig. 1) because the reaction is known to be rapid and the products stable [21].…”

“…Thus, based on its excellent reproducibility, this method was applied to the analysis of all the real samples mentioned above, yielding electrophoretic profiles (a typical example is reported in trace b) comparable to the HPLC patterns. Given this strong similarity, peaks 1, 2, and 3 were identified essentially by spiking a few samples chosen at random (NS 25 , MS 10 , HS 15 were chosen) with authentic compounds and verifying the comigration of the relative peaks. Traces c, d, and e represent the increase of peaks 1, 2, and 3 upon co-injection, with the samples indicated, of standard FA, AA, and AC, respectively.…”

“…Carbonyl compounds, including the low-aliphatic aldehydes formaldehyde, acetaldehyde and acrolein, have been shown to be major air pollutants since they can be generated directly from incomplete fossil fuel combustion or indirectly by photochemical oxidation of volatile organic compounds emitted by various industrial sources [2,3]. Given the toxic potential of these molecules, sensitive techniques are needed to detect them even at low concentrations and indeed a series of reliable chromatographic (HPLC) and capillary electrophoretic (CE) approaches have already been developed for their exact quantification in air and other environmental samples [4][5][6][7][8][9][10] and in human exhaled breath condensate [11]. In addition, since the above-mentioned aldehydes are also major components of cigarette smoke, gas and liquid chromatographic techniques have been specifically designed for determining their amount in sidestream and mainstream cigarette smoke [12][13][14].…”

Avaliação de contaminantes inorgânicos e orgânicos em álcool combustível utilizando eletroforese capilar

“…Os parâmetros instrumentais e analíticos foram selecionados com base na literatura 29 . A MEKC é usualmente feita com um eletrólito de corrida, que contém somente um tampão e um tensoativo.…”

Applications of capillary electrophoresis to the analysis of compounds of clinical, forensic, cosmetological, environmental, nutritional and pharmaceutical importance

“…12, 13 Lately, we been investigating several analytical possibilities for the CE evaluation of aldehydes in atmospheric air. [14][15][16] Figure 5 presents two analytical possibilities for the analysis of aldehydes by free solution capillary electrophoresis: separation of anionic bisulfite-aldehyde adducts in vehicular emission and 4-hydrazine benzoic acid (HBA)-aldehyde derivatives in indoor air samples.…”