A new electroanalytical methodology for the determination of formaldehyde in wood-based products

Gas-diffusion microextraction combined with HPLC-DAD for the comprehensive analysis of volatile carbonyl compounds in wood-based panels

This work presents a novel application of gas-diffusion microextraction (GDME) combined with high-performance liquid chromatography with diode-array detection (HPLC-DAD) for the comprehensive analysis of volatile carbonyl compounds released from wood-based panels. GDME is a simple, fast, and environmentally friendly technique that allows the simultaneous extraction and derivatization of volatile carbonyls directly from solid samples. Commercial particleboards were analysed together with particleboard panels specifically produced using controlled conditions, materials, and reagents, to evaluate the differences in the emission profile of volatile carbonyl compounds. The effect of different production parameters, such as the type of wood particle, resin, and moisture content, on the emission profile of volatile carbonyls from particleboards was investigated using principal component analysis (PCA). The results showed that GDME-HPLC-DAD could successfully differentiate particleboards according to their emission of carbonyl compounds, such as formaldehyde, furfural, benzaldehyde, and other aliphatic carbonyls. Besides the differences on the emission of formaldehyde caused by the type of resin used, UF (urea-formaldehyde) and mUF (UF fortified with melamine), it was found that pine (Pinus pinaster Ait.) particleboards exhibit higher emissions of compounds such as acetaldehyde or hexanal when compared to the higher emissions of compounds such as furfural or benzaldehyde on the recycled particleboards.

Recent Advances in Electrochemical Sensors for Formaldehyde

Formaldehyde, a ubiquitous indoor air pollutant, plays a significant role in various biological processes, posing both environmental and health challenges. This comprehensive review delves into the latest advancements in electrochemical methods for detecting formaldehyde, a compound of growing concern due to its widespread use and potential health hazards. This review underscores the inherent advantages of electrochemical techniques, such as high sensitivity, selectivity, and capability for real-time analysis, making them highly effective for formaldehyde monitoring. We explore the fundamental principles, mechanisms, and diverse methodologies employed in electrochemical formaldehyde detection, highlighting the role of innovative sensing materials and electrodes. Special attention is given to recent developments in nanotechnology and sensor design, which significantly enhance the sensitivity and selectivity of these detection systems. Moreover, this review identifies current challenges and discusses future research directions. Our aim is to encourage ongoing research and innovation in this field, ultimately leading to the development of advanced, practical solutions for formaldehyde detection in various environmental and biological contexts.

Development of a colorimetric sensor based on the coupling of a microfluidic paper-based analytical device and headspace microextraction for determination of formaldehyde in textile, milk, and wastewater samples

A user-friendly, cost-effectively, portable, and environmentally friendly colorimetric sensor for the quantitative determination of formaldehyde was developed based on the combining of microfluidic paper-based analytical device (μPAD), headspace microextraction (HSME), and digital image colorimetry. Coupling HSME and μPAD led to enhancements in selectivity and sensitivity of the sensor through sample cleanup and analyte enrichment. To construct the μPAD-HSME device, two pieces of paper as the sample and detection zone were placed facing each other so that a small common and sealed space was created between them. The color change occurred when the analyte in the gaseous form crossed this gap and reached the detection zone. Colorimetric sensing in the detection zone was performed based on the Hantzsch reaction. The color change in the detection zone was recorded by a smartphone and digital images were processed using image analysis software based on the RGB model. The influence of some key variables on the sensitivity of the method including derivatization reagent composition, sample volume, extraction temperature, and extraction time was studied and optimized. The linear dynamic range of the method was obtained in two ranges of 0.10-0.75 and 0.75-5.0 mg L-1 with a limit of detection of 0.03 mg L-1. The recoveries were in the range 80-126% for the quantification of formaldehyde in textile, milk, and wastewater samples.

A Novel Fluorescent and Colorimetric Method for the Determination of Formaldehyde Based on Albumin Nanoparticles-Polyethyleneimine-Ag+ Ion Nanohybrids

As a carcinogenic substance, high dose of formaldehyde exposure may lead to poisoning and even death. Long-term exposure to low doses of formaldehyde can harm human skin, respiratory organs and immune system. Therefore, it is vital to detect formaldehyde content in real time. In this paper, a simple method for the determination of formaldehyde based on fluorometry and colorimetry was established in the range of 0-1.92 mg·mL-1. A fluorescence protein nanoparticles (BSA NPs) was prepared utlizing bovine serum albumin (BSA) as the raw material. Based on the silver mirror reaction, silver nanoparticles can be generated from the reaction between BSA NPs combined with polyethylenimide (PEI) and silver ion (Ag+) ions complex (BSA NPs-PEI-Ag) and formaldehyde. The fluorescent detection principle for formaldehyde was based on the fluorescence queching of BSA NPs-PEI-Ag system at 514 nm upon the reduction of Ag+ ions by formaldehyde. The colorimetric detection principle for formaldehyde was based on the enhancement of absorption band of BSA NPs-PEI-Ag system at 460 nm and color changes along with the generation of silver nanoparticles after the addition of formaldehyde. The proposed method was succesfully used for formaldehyde detection in real water sample with the recovery range of 106-110%.

Bismuth-coated screen-printed electrodes for the simple voltammetric determination of formaldehyde

For the first time, bismuth modified electrodes have been used for the voltammetric detection of formaldehyde (FM). The well-known method of forming formaldehyde hydrazone (FAH) in the presence of hydrazine sulphate was used to convert the hydrated form of FM into its electrochemically active derivative. Various experimental conditions for differential pulse voltammetry were studied to achieve the best analytical performance. The FAH reduction current (FM response) reaches its maximum value at a pH of a phosphate buffer solution of 5.2 ± 0.1 in the presence of 0.09-0.12 M hydrazine sulfate on a bismuth film preliminarily precipitated for 8-12 min from acidic Bi(III) acetate solutions at an electrolysis potential of -1.0 V on the surface of a screen-printed carbon electrode (SPCE). A dendritic-like film structure was created on the SPCE surface. Under the optimized conditions a linear calibration curve over the range of 0.01-5 mg L^-1 (0.33-167 μM) FM was achieved, with a detection limit of 0.002 mg L^-1 (0.06 μM). The determination of FM in waste water, melt water from snow within the city industrial zone, and a widely used pharmaceutical preparation "Endofalk®" with good results revealed the potential applicability of a bismuth modified SPCE (BiSPCE) for trace analysis.

Enzyme decorated dendritic bimetallic nanocomposite biosensor for detection of HCHO

In recent times, bi- and tri-metallic nanocomposites are being extensively studied to improve the catalytic surface and sensitivity of detection. In this study, we designed a formaldehyde dehydrogenase decorated Cys-AuPd-ErGO nanocomposite with fern like AuPd dendrites deposited on reduced graphene oxide (ErGO) on screen printed electrode (SPE) for determination of NADH and successfully demonstrated its application for detection of HCHO. This biosensor exhibited direct electron transfer by lowering the oxidation potential of NADH from +0.63 V to 0.32 V vs Ag/AgCl, avoiding usage of electron mediators. The sensor LOD was 0.3 μM HCHO with excellent sensitivity of 70 μA/μM/cm² and linear detection range between 1 μM and 100 μM during chronoamperometric studies at applied over potential of +0.35 V vs Ag/AgCl. The sensor was tested for its performance in simulated HCHO adulterated samples of fish and milk, and appreciable recoveries (88-104%) at tested concentrations indicated good sensor performance. It was also validated against conventional method of HPLC with highly acceptable correlation coefficient of 0.99, indicating successful fabrication of a simple, "on site" disposable sensor for HCHO detection. The developed biosensor can also find wide application in quantitative measurement of NADH and analytes involved in reactions with the co-enzyme.