Effect of pH on the reaction of 2,4-dinitrophenylhydrazine with formaldehyde and acetaldehyde

Bicking, Merlin K. L.; Cooke, W.M.; Kawahara, Fred K.; Longbottom, James E

doi:10.1016/s0021-9673(01)82130-0

Cited by 33 publications

(13 citation statements)

References 15 publications

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“…The acid-catalyzed reaction had an optimum pH 4.0, since the rate-limiting step is the protonation of carbonyl oxygen, followed by the loss of water to form hydrazone. An optimum pH of 4.0 for the derivatization reaction was also found by Kozutsumi et al (2002), though stronger acidic conditions have been also reported (Bicking et al, 1988; Cotsaris and Nicholson, 1993). The reaction at the optimum pH was completed within 40 min at ambient temperature or with longer incubation at 4°C (see Fig.…”

Section: Discussionmentioning

confidence: 77%

“…The rate-limiting step is the condensation of the hydrazine group (NH 2 -NH-) of DNPH to the protonated carbonyl moiety ( + HC=O) of acetaldehyde. At different pH there are competing effects between the acetaldehyde and DNPH reactive states, and the availability of DNPH dominates the optimum pH (Bicking et al, 1988). The formation of AcH-DNP as a function of pH is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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An Optimized Method for the Measurement of Acetaldehyde by High‐Performance Liquid Chromatography

Guan

Rubin

Anni

2011

Alcoholism Clin & Exp Res

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Background Acetaldehyde is produced during ethanol metabolism predominantly in the liver by alcohol dehydrogenase, and rapidly eliminated by oxidation to acetate via aldehyde dehydrogenase. Assessment of circulating acetaldehyde levels in biological matrices is performed by headspace gas chromatography and reverse phase high-performance liquid chromatography (RP-HPLC). Methods We have developed an optimized method for the measurement of acetaldehyde by RP-HPLC in hepatoma cell culture medium, blood and plasma. After sample deproteinization, acetaldehyde was derivatized with 2,4-dinitrophenylhydrazine (DNPH). The reaction was optimized for pH, amount of derivatization reagent,, time and temperature. Extraction methods of the acetaldehyde-hydrazone (AcH-DPN) stable derivative and product stability studies were carried out. Acetaldehyde was identified by its retention time in comparison to AcH-DPN standard, using a new chromatography gradient program, and quantitated based on external reference standards and standard addition calibration curves in the presence and absence of ethanol. Results Derivatization of acetaldehyde was performed at pH 4.0 with a 80-fold molar excess of DNPH. The reaction was completed in 40 min at ambient temperature, and the product was stable for 2 days. A clear separation of AcH-DNP from DNPH was obtained with a new 11-min chromatography program. Acetaldehyde detection was linear up to 80 μM. The recovery of acetaldehyde was >88% in culture media, and >78% in plasma. We quantitatively determined the ethanol-derived acetaldehyde in hepatoma cells, rat blood and plasma with a detection limit around 3 μM. The accuracy of the method was <9% for intraday and <15% for interday measurements, in small volume (70 μl) plasma sampling. Conclusions An optimized method for the quantitative determination of acetaldehyde in biological systems was developed using derivatization with DNPH, followed by a short RP-HPLC separation of AcH-DNP. The method has an extended linear range, is reproducible and applicable to small volume sampling of culture media and biological fluids.

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Section: Discussionmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

An Optimized Method for the Measurement of Acetaldehyde by High‐Performance Liquid Chromatography

Guan

Rubin

Anni

2011

Alcoholism Clin & Exp Res

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“…Collection efficiency of the DNPH solution-wetted filter/denuder type sampler could also be affected by pH, humidity, and characteristics of target carbonyl compounds ( Kallinger and Niessner, 1997 ; John et al, 2020 ). Reaction between DNPH and carbonyl compounds are more efficient at acidic conditions than at neutral pH ( Bicking et al, 1988 ). Our continuously wetting system supplying fresh DNPH solution to the filter/denuder minimizes pH changes over time, but the impacts of nicotine (pKa = 8.0) and other e-liquid constituents on pH need to be studied.…”

Section: Discussionmentioning

confidence: 99%

An Automated Aerosol Collection and Extraction System to Characterize Electronic Cigarette Aerosols

Son

Khlystov

2021

Front. Chem.

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Electronic cigarette (e-cigarette) market increased by 122% during 2014–2020 and is expected to continue growing rapidly. Despite their popularity, e-cigarettes are known to emit dangerous levels of toxic compounds (e.g., carbonyls), but a lack of accurate and efficient testing methods is hindering the characterization of e-cigarette aerosols emitted by a wide variety of e-cigarette devices, e-liquids, and use patterns. The aim of this study is to fill this gap by developing an automated E-cigarette Aerosol Collection and Extraction System (E-ACES) consisting of a vaping machine and a collection/extraction system. The puffing system was designed to mimic e-cigarette use patterns (i.e., power output and puff topography) by means of a variable power-supply and a flow control system. The sampling system collects e-cigarette aerosols using a combination of glass wool and a continuously wetted denuder. After the collection stage, the system is automatically washed with absorbing and extracting liquids (e.g., methanol, an acetaldehyde-DNPH solution). The entire system is controlled by a computer. E-ACES performance was evaluated against conventional methods during measurements of nicotine and carbonyl emissions from a tank type e-cigarette. Nicotine levels measured using glass fiber filters and E-ACES were not significantly different: 201.2 ± 6.2 and 212.5 ± 17 μg/puff (p = 0.377), respectively. Differences in formaldehyde and acetaldehyde levels between filter-DNPH cartridges and the E-ACES were 14% (p = 0.057) and 13% (p = 0.380), respectively. The E-ACES showed reproducible nicotine and carbonyl testing results for the selected e-cigarette vaping conditions.

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“…In the EN ISO 17226-1 standard conditions, the DNPH is in an orthophosphoric acid solution. Harsh acidic conditions (the pH in the derivatization flask is about 1.3) are known to catalyse the derivatization reaction with DNPH but also to favour resin hydrolysis [18]. The first alternative consists in using less acidic and/or buffered media.…”

Section: New Derivatization Conditions For the Analysis Of Formaldehymentioning

confidence: 99%

Towards a Non-Biased Formaldehyde Quantification in Leather: New Derivatization Conditions before HPLC Analysis of 2,4-Dinitrophenylhydrazine Derivatives

et al. 2020

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In leathers, formaldehyde is currently analyzed according to EN ISO 17226-1 standard, by reversed phase liquid chromatography after off-line precolumn derivatization with 2,4 dinitrophenylhydrazine (DNPH) in strong acidic conditions. We first demonstrate that this standard is not adapted to leather retanned with resins likely to release formaldehyde by hydrolysis. Indeed, formaldehyde content may be largely overestimated due to concomitant resin hydrolysis (in harsh acidic conditions) that releases formaldehyde during the derivatization step and during the waiting time on autosampler before analysis. Therefore, we thoroughly studied the derivatization step in order to propose new derivatization conditions. Replacing orthophosphoric acid by less acidic buffer solutions is not enough to avoid hydrolysis. A derivatization without adding acid is realized by solubilizing DNPH in acetonitrile instead of orthophosphoric acid. These conditions lead to a complete derivatization of formaldehyde in 3 h at 50 °C (in a water bath) while avoiding the hydrolysis of co-extracted dicyandiamide and melamine resins. The as-obtained leather extracts are stable over time. Formaldehyde contents found with this method agree with the formaldehyde content measured immediately at the end of derivatization reaction in standard conditions or with formaldehyde content measured by a home-designed flow injection analysis with acetylacetone online derivatization and UV detection.

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Effect of pH on the reaction of 2,4-dinitrophenylhydrazine with formaldehyde and acetaldehyde

Cited by 33 publications

References 15 publications

An Optimized Method for the Measurement of Acetaldehyde by High‐Performance Liquid Chromatography

An Optimized Method for the Measurement of Acetaldehyde by High‐Performance Liquid Chromatography

An Automated Aerosol Collection and Extraction System to Characterize Electronic Cigarette Aerosols

Towards a Non-Biased Formaldehyde Quantification in Leather: New Derivatization Conditions before HPLC Analysis of 2,4-Dinitrophenylhydrazine Derivatives

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