Recovery Of Formaldehyde Research Articles

Casein/ferric chloride/polyvinyl alcohol composite for specific in-syringe colorimetric detection of formaldehyde in Hevea brasiliensis latex.

A new, simple, and selective colorimetric method of determining formaldehyde in Hevea brasiliensis latex was developed by using a casein/ferric chloride/polyvinyl alcohol hydrogel composite (casein/FeCl3/PVA) in a modified Leach test. Under heating, formaldehyde reacted with 8% casein in the presence of 0.1% FeCl3 and 4.3% HCl (v/v) entrapped in a 30% PVA hydrogel packed in a syringe. A purple-colored product was formed with a maximum absorbance of 525nm. The color change was evaluated at the color detection zone indicated on thethe syringe. The %magenta values were easily evaluated by using a mobile phone application and employed to determine formaldehyde content. The casein/FeCl3/PVA composite gave a readable response in a formaldehyde detection range from 0.04 to 0.80% with a linear response between %magenta and formaldehyde concentration (R2 = 0.9955). The detection limit was 0.032%, and precisions were in the range 0.67-4.94%. The casein/FeCl3/PVA composite was applied to the analysis of ammonia-preserved latex samples, and recoveries of formaldehyde from samples spiked at 0.1, 0.3, and 0.5% ranged from 81.55 to 99.51% (RSDs ≤ 5.41%). The recoveries and precision of the proposed method were comparable with those of high-performance liquid chromatography (HPLC). The developed method was also selective, showing no interference from other latex preservatives, i.e., phenol, ammonia, or tetramethylthiuram disulfide.

A sensitive fluorometric-colorimetric dual-mode intelligent sensing platform for the detection of formaldehyde

Excess formaldehyde (FA) is a strong carcinogen, so the development of a rapid visualized and portable formaldehyde detection platform is of great research importance. A multi-color fluorescence sensing system constituted of model compound (NAHN) and red-emitting InP/ZnS QDs was constructed herein, which can simultaneously realize fluorometric-colorimetric dual-mode sensing when exposed to FA environment. Its preparation process was simplified, the detection process was green, and the limits of detection (LOD) were 0.623 μM and 0.791 μM, respectively. The high recoveries of FA in actual water samples indicated that the sensor had broad application prospects. The prepared fluorescent film can be utilized for rapid visual simulation analysis of FA on the surface of various fruits and vegetables. In addition, a serial logic gate was designed to quickly semi-quantitatively assess FA concentration, which promoted the realization of on-site intelligent evaluation of FA.

Study on the application of sulfonation catalysis in a new formaldehyde recovery process

This study proposed a new catalytic conversion process using a sulfonated catalyst to promote the condensation reaction of methanol and formaldehyde (FA) to form methylal (DMM). This method can remove FA while generating the valuable chemical product DMM. A series of SiO 2 -xSO 3 H catalysts were developed, and the synergistic effect of the sulfonic acid group vacancy and hydroxyl vacancy contents was evaluated by adjusting the activation temperature and sulfonation ratio. When the activation temperature was 60 °C, the FA yield reached 82.3%, and DMM selectivity was 80.4%. The FA recovery rate was much higher than in other studies. A series of characterization studies revealed that when there were few -SO 3 H groups, the hydroxyl content increased, providing more activation centers for forming the formic acid by-product from FA. The dehydration and condensation of formic acid and methanol formed methyl formate (MF). However, when there were too many -SO 3 H groups, side reactions of methanol and FA occurred preferentially. Therefore, the synergistic effect of the -SO 3 H group and hydroxyl group content was the fundamental reason for the exceptional catalytic performance. Furthermore, in-situ infrared spectroscopy revealed the possible reaction mechanism of methanol and FA on sulfonated silica gel and verified the conclusion drawn from the catalyst characterization. This approach overcomes the disadvantages of the high cost of FA absorption and difficulty of industrialization due to the high reaction temperature and provides the potential to “turn waste into treasure” during FA recovery while providing new avenues to solving the problem of FA pollution.

Study on the optimized Al2O3–SO3H catalysis for a new formaldehyde recovery process

Formaldehyde is a dangerous chemical present in many industrial waste gases. It can be recovered via catalytic processes; however, many of these require costly precious metals operating under limited reaction temperatures, making their industrialization difficult. This paper proposes a novel method of formaldehyde recovery. A sulfonation catalyst is used to promote a condensation reaction of methanol and formaldehyde to form methylal. Hence, a valuable chemical product is obtained while removing formaldehyde. A series of Al2O3-xSO3H catalysts were designed and the effects of surface acidity and hydroxyl groups on catalytic activity were explored by varying the activation temperature and sulfonation ratio. At an activation temperature of 60 °C, the yield of formaldehyde reaches 78.62% and the selectivity to methylal reaches 80.11%. This recovery rate is much higher than those reported in other studies. Through a series of characterizations, it was found that when the content of –SO3H groups is low, the hydroxyl content increases, which provides more activation centers for the formation of by-product formic acid from formaldehyde, and for the dehydration and condensation of formic acid and methanol to form methyl formate. At the same time, when the content of –SO3H groups is too high, side reactions of methanol and formaldehyde occur preferentially. Therefore, the synergistic effect of the contents of –SO3H and hydroxyl groups is the fundamental cause of the excellent catalytic performance. Based on in-situ infrared research, a possible mechanism of the reaction between methanol and formaldehyde on sulfonated silica gel is proposed, which also verifies the characterization of the catalyst. This research presents new possibilities for solving the problem of formaldehyde pollution.

Determination of Formaldehyde Yields in E-Cigarette Aerosols: An Evaluation of the Efficiency of the DNPH Derivatization Method

Recent reports have suggested that (1) formaldehyde levels (measured as a hydrazone derivative using the DNPH derivatization method) in Electronic Nicotine Delivery Systems (ENDS) products were underreported because formaldehyde may react with propylene glycol (PG) and glycerin (Gly) in the aerosol to form hemiacetals; (2) the equilibrium would shift from the hemiacetals to the acetals in the acidic DNPH trapping solution. In both cases, neither the hemiacetal nor the acetal would react with DNPH to form the target formaldehyde hydrazone, due to the lack of the carbonyl functional group, thus underreporting formaldehyde. These reports were studied in our laboratory. Our results showed that the aerosol generated from formaldehyde-fortified e-liquids provided a near-quantitative recovery of formaldehyde in the aerosol, suggesting that if any hemiacetal was formed in the aerosol, it would readily hydrolyze to free formaldehyde and, consequently, form formaldehyde hydrazone in the acidic DNPH trapping solution. We demonstrated that custom-synthesized Gly and PG hemiacetal adducts added to the DNPH trapping solution would readily hydrolyze to form the formaldehyde hydrazone. We demonstrated that acetals of PG and Gly present in e-liquid are almost completely transferred to the aerosol during aerosolization. The study results demonstrate that the DNPH derivatization method allows for an accurate measurement of formaldehyde in vapor products.

Smartphone-based digital images as a novel approach to determine formaldehyde as a milk adulterant

Milk is an important source of protein and its consumption has gained relevance because of new evidence for its nutritional and functional role for humans. On the other hand, milk quality has been hindered by tampering, including the addition of formaldehyde to mask product deterioration and increase its shelf life, although this substance may cause harm to consumers. Taking these aspects into account, a novel, fast, greener, portable, and cost-effective method is proposed for the determination of formaldehyde in milk. This method relies on smartphone-based digital image colorimetry of the product formed upon reaction with the Schiff reagent, followed by conversion of the images into RGB values using free application software. Sample preparation only involved protein precipitation in an acidic medium and analyte determination required only a few micrograms of the reagents. The proposed method achieved a limit of detection as low as 120 μg L−1 formaldehyde with a linear response up to 1250 μg L−1 and good precision (CV = 2%, n = 20). Matrix effects were negligible after protein precipitation with recoveries of formaldehyde spiked milk samples within 92–106%. The accuracy was assessed using a reference procedure (HPLC with UV detection after analyte derivatization and liquid–liquid extraction) and the results agreed at the 95% confidence level. The procedure is applicable to whole, semi-skim, and skim milk processed using pasteurization or ultra-heat treatment (UHT).

New light-sensitive materials based on TiO2 and merocianin polymetine dye

The influence of the structure of a number of merocyanine dyes (D), which differ in the length of the polyethylene chain on one vinyl group, on their spectral, electrochemical and energy characteristics is established. Cyclic voltammetry determines their oxidation and reduction potentials. The values ​​of the HOMO and LUMO energy levels of the studied dyes from spectral and electrochemical data were calculated. It is shown that the obtained values ​​of the potentials of the energy levels of the dyes differ little (the energy difference ranges from 0,22–0,53 eV). The possibility of using merocyanins as sensitizers of titanium(IV) oxide and the creation of photosensitive heterostructures has been made. In order to investigate the possibility of using the merocyanin dyes under study as TiO2 sensitizers, the energy of the «semiconductor – dye – reagents» systems was considered. For this purpose, we compared the redox characteristics of merocyanine dyes with the electrophysical parameters of titanium(IV) oxide, as well as the redox characteristics of the reaction participants. It is established that in such systems the processes of photon transfer of the electron from the dye to the semiconductor are necessary for sensitization, and the regeneration of the original form of the sensitizers by the action of the reducing agent on the cation radicals formed is thermodynamically allowed. The conclusion about the possibility of using the studied merocyanines as effective sensitizers was confirmed by the results of the study of the photocatalytic activity of D/TiO2 heterostructures in the reaction of methylene blue formaldehyde recovery under different irradiation conditions and at different dye concentrations. The explanation for the found laws is offered. Scientific approaches to the production of new photosensitive systems with an expanded range of photosensitivity and a given level of photocatalytic activity have been developed.

A hydrophobic deep eutectic solvent based vortex-assisted liquid-liquid microextraction for the determination of formaldehyde from biological and indoor air samples by high performance liquid chromatography

Hydrophobic deep eutectic solvents (DESs) are a new class of green solvents, and their research and application are a brand new area. So far, only a few hydrophobic DESs have been reported as extraction solvents. In this paper, five kinds of hydrophobic DESs composed of trioctylmethylammonium chloride and hydroquinone, 4-phenylphenol or 4-cyanophenol are designed and prepared for the first time. Melting point / glass transition temperature and density are also determined for these DESs. Coupled with HPLC, these hydrophobic DESs have been used as extractants in vortex-assisted liquid-liquid microextraction for the selective enrichment and indirect determination of formaldehyde. The optimization of reaction and extraction conditions, such as pH value, reaction time and temperature, concentration of 2,4-dinitrophenylhydrazine, type and dosage of the extraction solvent, speed and time of vortex, salt addition and centrifugation time are investigated in detail. It is found that under the optimized experimental conditions, the calibration curve of this method is linear in the range of 1.0–200.0 μg L−1 with the linear correlation coefficient (r2) of 0.9994. The limit of detection (S/N = 3) and limit of quantification (S/N = 10) are 0.2 μg L−1 and 1.0 μg L−1, and the intra-day and inter-day precision (RSD, n = 5) are 1.1% and 3.5%, respectively. The interference of some common coexisting ions and neutral molecules have been also tested. The proposed method has been successfully used for the determination of formaldehyde from biological and indoor air samples. The recovery of formaldehyde is in the range from 83.1% to 104.4%, and the relative standard deviation is lower than 5.9%. Furthermore, the analytical parameters of the proposed method have been compared with other extraction and microextraction methods.

Determination of Formaldehyde by HPLC with Stable Precolumn Derivatization in Egyptian Dairy Products.

Formaldehyde is one of the most dangerous chemical compounds affecting the human health; exposure to it from food may occur naturally or by intentional addition. In this study a high performance liquid chromatography method for determination of formaldehyde in dairy products was described. The dairy samples were reacted and extracted with a warmed organic solvent in the presence of derivatizing agent 2,4-dinitrophenylhydrazine (DNPH) and formaldehyde; the mixture was centrifuged and followed by diode array detection. The method is validated and gives average recovery of formaldehyde at the three different levels 0.1, 5.0, and 10.0 mg/kg varied between 89% and 96%. The method is linear from the limit of quantification 0.1 mg/kg up to 10 mg/kg levels. This method is intended for formaldehyde analyses in dairy products simply with stable derivatization, minimum residue loss, excellent recovery, and accurate results with a sensitive limit of detection 0.01 mg/kg. 90 dairy samples from milk, cheese, and yogurt were investigated from seven Egyptian governorates and all samples were free from formaldehyde.

Metal-organic frameworks as superior media for thermal desorption-gas chromatography application: A critical assessment of MOF-5 for the quantitation of airborne formaldehyde

In this study, formaldehyde (FA) in the air was collected and analyzed using metal-organic framework-5 (MOF-5) as the sorbent material (for both sorbent tube (ST) sampling and thermal desorption (TD) analysis) in gas chromatography-mass spectrometry (GC-MS) detection. A series of experiments was carried out to determine the optimal analytical conditions for maximum recovery of FA by TD-GC-MS. Optimal TD conditions for adsorption and desorption of MOF-5 were determined to be −25°C and 100°C, respectively. These conditions yielded good linearity (R2=0.9975), precision (mean 1.79±1.17%), and high sensitivity. The method detection limit (MDL) of 0.1ng was attained to determine 0.82ppb of FA in 100mL of air (limit of detection (LOD) of 8pg (0.06ppb)). The concentration of FA, when measured from ambient air samples using MOF-5, averaged 9.67ppb (n=3, RSE=2.39%). FA samples, when analyzed in parallel using the DNPH cartridge-HPLC-UV system recommended by the US EPA, yielded similar results (mean of 10.5ppb) to the MOF-5 dataset. In addition, trace quantities of FA (0.25ng) were also detected from samples of as little as 20mL of air. Our results suggest that MOF-5 is a suitable sorbent media for thermal desorption analysis and in fact surpasses the performance of commercial sorbents used for VOC analysis. As such, a GC-based detection method for FA comprising simple thermal desorption without complicated procedures, such as a derivatization step, was realized.

Determination of formaldehyde and acetaldehyde in packaging paper by dansylhydrazine derivatization-high performance liquid chromatography-fluorescence detection

A high performance liquid chromatography with fluorescence detection (HPLC-FLD) method was developed for the simultaneous determination of formaldehyde and acetaldehyde in packaging paper by dansylhydrazine (DNSH) derivatization. The samples were extracted by derivatization reagent for 30 min, and derived for 24 h. After purifying treatment with a PSA/C18 cartridge, a Diamonsil® C18 column (150 mm×4.6 mm, 5 μ m) was used as stationary phase for separation, the mixtures of acetic acid aqueous solution (pH 2.55)-acetonitrile were used as mobile phases by gradient elution, and the excitation and emission wavelengths were 330 nm and 484 nm, respectively. The results showed that the recoveries of formaldehyde and acetaldehyde spiked in the samples were 81.64%-106.78%, and the relative standard deviations (RSDs) were 2.02%-5.53% (n=5). The limits of detection of formaldehyde and acetaldehyde were 19.2 μ g/kg and 20.7 μ g/kg, respectively. The limits of quantification of formaldehyde and acetaldehyde were 63.9 μ g/kg and 69.1 μ g/kg, respectively. The method is simple, sensitive and reproducible. It provides a basic approach for the determination of trace formaldehyde and acetaldehyde.

Simple Milligram-Scale Extraction of Formaldehyde from Wood

Lignocellulose naturally contains formaldehyde, and generates much more when heated. A simple quantitation of such biogenic formaldehyde is desirable for the analysis and utilization of lignocellulose. Heretofore, a boiling toluene extraction (the perforator method) was the best known technique to determine biogenic formaldehyde in wood. Described here is a simple milligram-scale water extraction that avoids specimen heating. This method was validated by comparison to a laborious extraction using poly(allylamine), PAA, beads that strongly sorb formaldehyde. The PAA-based extraction and the water-only extraction were found to be effectively equivalent, recovering about 94% of wood formaldehyde. The incomplete formaldehyde recovery is offset by experimental simplicity, and suitability for large sampling. For instance, the new method was applied to the analysis of tree increment cores; formaldehyde levels measured in never-heated Pinus virginiana ranged from 1 to 5 μg/g dry wood, and were comparable to publi...

Simple high‐performance liquid chromatography method for formaldehyde determination in human tissue through derivatization with 2,4‐dinitrophenylhydrazine

A simple high-performance liquid chromatography method has been developed for the determination of formaldehyde in human tissue. FA Formaldehyde was derivatized with 2,4-dinitrophenylhydrazine. It was extracted from human tissue with ethyl acetate by liquid-liquid extraction and analyzed by high-performance liquid chromatography. The calibration curve was linear in the concentration range of 5.0-200μg/mL. Intra- and interday precision values for formaldehyde in tissue were <6.9%, and accuracy (relative error) was better than 6.5%. The extraction recoveries of formaldehyde from human tissue were between 88 and 98%. The limits of detection and quantification of formaldehyde were 1.5 and 5.0μg/mL, respectively. Also, this assay was applied to liver samples taken from a biopsy material.

Exploitation of pulsed flows for on-line dispersive liquid–liquid microextraction: Spectrophotometric determination of formaldehyde in milk

Formaldehyde is often added to foods as a preservative, but it is highly toxic to humans, having been identified as a carcinogenic substance. It has also been used for the adulteration of milk in order to diminish the bacteria count and increase the shelf life of the product. Herein, we present a green dispersive liquid–liquid microextraction procedure in a flow-batch system for the determination of formaldehyde in milk. Pulsed flows were exploited for the first time to improve the dispersion of the extractant in the aqueous phase. The Hantzsch reaction was used for the derivatization of formaldehyde and the product was extracted with the ionic liquid (IL) trihexyltetradecylphosphonium chloride with methanol as the disperser. The flow-batch chamber was made of stainless steel with the facility for resistive heating to speed up the derivatization reaction. Spectrophotometric measurements were directly carried out in the organic phase using an optical fiber spectrophotometer. The limit of detection and coefficient of variation were 100μgL−1 and 3.1% (n=10), respectively, with a linear response from 0.5 to 5.0mgL−1, described by the equation A=0.088+0.116CF (mgL−1) in which A is absorbance and CF is formaldehyde concentration in mgL−1. The estimated recoveries of formaldehyde from spiked milk samples ranged from 91% to 106% and the slopes of the analytical curves obtained with reference solutions in water or milk were in agreement, thus indicating the absence of matrix effects. Accuracy was demonstrated by the agreement of the results with those achieved by the reference fluorimetric procedure at the 95% confidence level. The proposed procedure allows for 10 extractions per hour, with minimized reagent consumption (120μL of IL and 3.5μL acetylacetone) and generation of only 6.7mL waste per determination, which contribute to the eco-friendliness of the procedure.

Determination of formaldehyde in aqueous samples with a miniaturized extraction capillary coupled to high-performance liquid chromatography.

A novel analytical method for determining formaldehyde (FA) in aqueous samples was developed with a miniaturized extraction capillary in high-performance liquid chromatography (HPLC). The extraction capillary was prepared by packing silica gel particles in a stainless steel capillary of 0.8 mm i.d. and 1.6 mm o.d. A derivatization reagent of 2,4-dinitrophenylhydrazine (DNPH) was impregnated on the silica gel particles by pumping a solution of DNPH to the capillary. Two extraction methods; dynamic extraction and purge-and-trap (PT) methods, were investigated for derivatizing and extracting FA from water samples onto the silica gel in the extraction capillary. The extraction capillary was directly connected to a six-port valve, and then desorption of the derivative from the capillary and injection to conventional HPLC system were simultaneously achieved with a flow of acetonitrile through the capillary. In the dynamic extraction, FA was determined with a simple sample preparation procedure, and the limit of detection (LOD) was 18 μg L(-1) at a sample volume of 20 mL, while several limitations were found in the method, such as bleeding of the derivatization reagent and the corresponding derivatized FA from the capillary during the sample load/extraction process. The sensitivity was significantly improved by introducing a PT technique, where the LOD was 6.9 μg L(-1) at a sample volume of 20 mL with a sampling time of approximately 20 min. With the PT method, successful recoveries of FA were confirmed for spiked tap water, river water and fruit juice samples.

Applied Research on the Resource Recovery of Formaldehyde in Pesticide Wastewater

Applied research on the technology of resource recovery of formaldehyde in pesticide wastewater through compression distillation was accomplished intensively in this study. Vapor–liquid equilibrium data of the low-molar fraction formaldehyde aqueous solution were measured accurately in experiments. The results were in high accordance with the theoretical values through data association. It filled in a gap in data at the zone of low formaldehyde molar fraction (particularly below 0.006) and also provided theoretical basis for the distillation column design for recycling formaldehyde. Systematic experimental research investigated the recovery of formaldehyde in pesticide wastewater by compression distillation. The distillation column was operated under a top pressure of 0.2 to 0.4 MPa and with feed formaldehyde molar fraction range of approximately 0.006 to 0.03. The formaldehyde molar fractions at the top and bottom of column were 0.15 and 0.00072, respectively. Therefore, concentrated formaldehyde solutio...

Formulation approach for the development of a stable, lyophilized formaldehyde-containing vaccine

Formaldehyde has been used in the inactivation of a number of viral and bacterial toxins used in vaccines. In some cases, a small amount of formaldehyde may be necessary in order to prevent reversion back to the toxic state during storage. When a lyophilized preparation is required, care must be taken to ensure that formaldehyde is not lost during the process in order to ensure safety of the product. A design of experiments (DOEs) approach was taken to devise a stable, lyophilized, vaccine formulation. A formaldehyde-inactivated bacterial toxin was used as a model antigen. Entrapment of formaldehyde in an amorphous matrix and/or interactions with amorphous components was found to be required for complete recovery of formaldehyde during lyophilization. In formulations consisting of sucrose and citrate, formaldehyde could be recovered across a wide range of excipient concentrations. Stability of the antigen was dependent on formaldehyde concentration, with antigen stability decreasing with increasing formaldehyde concentration. This is in contrast to the risk of reversion which increases with decreasing concentrations of formaldehyde. Finally, variations in temperatures during annealing, primary drying, and secondary drying had no impact on formaldehyde recovery.

Determination of ultra-trace formaldehyde in air using ammonium sulfate as derivatization reagent and capillary electrophoresis coupled with on-line electrochemiluminescence detection

The reaction between formaldehyde and ammonium ion to produce hexamethylenetetramine is well known. The reaction conditions are very easily controlled in situ and the experiment operation is very simple. However, such derivatization reaction for trace formaldehyde determination using capillary electrophoresis (CE) electrochemiluminescence (ECL) has not been reported before. In this study, the application of ammoniun sulfate as derivatization reagent to in-situ determination of formaldehyde in air was reported. Based on ECL enhancement of tris(2,2′-bipyridyl)ruthenium(II) with hexamethylenetetramine, a novel approach for the determination of ultra-trace formaldehyde in air using CE coupled with on-line ECL of tris(2,2′-bipyridyl)ruthenium(II) has been developed. The parameters affecting separation and detection such as detection potential, concentration and pH of phosphate buffer, and electrokinetic voltage, were investigated. Under the optimal conditions, the linear concentration range of formaldehyde in air was from 0.48μg/m3 to 96mg/m3 (linear range covering 5 orders of magnitude). The limit of detection (3σ) was 0.15μg/m3. The relative standard deviations of peak height and migration time for six consecutive injection of 1ng/mL formaldehyde derivative were 0.9% and 0.8%, respectively. The recoveries of formaldehyde in air were between 99.3% and 101%.

Determination of formaldehyde in beverages using microwave-assisted derivatization and ionic liquid-based dispersive liquid–liquid microextraction followed by high-performance liquid chromatography

A simple method based on simultaneous microwave-assisted derivatization and ionic liquid-based dispersive liquid–liquid microextraction (IL-based DLLME) is proposed for the derivatization, extraction and preconcentration of formaldehyde in beverage samples prior to the determination by high-performance liquid chromatography (HPLC). Formaldehyde was in situ derivatized with 2,4-dinitrophenylhydrazine (DNPH) and simultaneously extracted and preconcentrated by using microwave-assisted derivatization and IL-based DLLME in a single step. Several experimental parameters, including type and volume of extraction solvent, type and volume of disperser, microwave power and irradiation time, volume of DNPH, pH of sample solution, and ionic strength were evaluated. When the microwave power was 120W, formaldehyde could be derivatized and extracted simultaneously only within 90s. Under optimal experimental conditions, good linearity was observed in the range of 0.5–50ng/mL with the correlation coefficient of 0.9965, and the limit of detection was 0.12ng/mL. The proposed method was applied to the analysis of different beverage samples, and the recoveries of formaldehyde obtained were in the range of 84.9–95.1% with the relative standard deviations lower than 8.4%. The results showed that the proposed method was a rapid, convenient and feasible method for the determination of formaldehyde in beverage samples.

Determination of Formaldehyde in Urine by Headspace Gas Chromatography

Formaldehyde is a carcinogen to which humans are exposed daily, but few methods are available to quantify formaldehyde in biological samples. We developed a simple, sensitive and rapid technique for the quantification of formaldehyde in urine by derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, using a headspace sampler coupled to a gas chromatograph equipped with an electron capture detector. The detection limit was 1.08 microg/L. The overall recovery of formaldehyde spiked in urine was 99%. The concentration of formaldehyde in urine obtained from healthy volunteers ranged from 56.85 to 144.57 microg/L. This method can be used successfully to measure formaldehyde in urine.