Formaldehyde Content Research Articles

Pulsatile Delivery of Methylphenidate Hydrochloride Pulsincap by Box-Behnken Design

The objective of this study was to prepare and evaluate Methylphenidate hydrochloride pulsatile drug delivery system using pulsincap technique by applying Box-Behnken design. The drug is a central nervous system (CNS) stimulant used in the treatment of attention deficit hyperactivity disorder (ADHD). Pulsincap system was prepared by using formaldehyde cross linked capsules. Capsules were filled with methylphenidate hydrochloride granules and hydrogel plug made of HPMC K100M is placed over granules to achieve desired drug release after lag time. The untreated cap was then fitted and sealed using 5% ethyl cellulose ethanolic solution to the formaldehyde treated capsule body. Granules were prepared by wet granulation technique using two polymers Ethyl cellulose and Eudragit RS100. Box-Behnken design was applied for optimization in which three independent variables, X1 = Drug: polymer ratio, X2 = Polymer: polymer ratio (Ethyl cellulose: Eudragit RS 100) and X3 = Plug weight were selected. Two dependent variables Y1 = lag time and Y2 = percent release were selected. The empty formaldehyde treated capsules were evaluated for physical appearance, solubility, capsule dimensions and formaldehyde content. Hydrogel plugs were evaluated for hardness & thickness of the plug, lag time and swelling index. Granules were evaluated for percentage yield, assay and flow properties. The prepared pulsincap formulations were evaluated for weight variation, content uniformity, capsule lock length, in-vitro dissolutions studies, drug kinetics and stability studies. Contour plots and Response surface plots indicated that with the increase in X1 and X3 there is increase in Lag time and decrease in % drug release and whereas with the increase in X2 the lag time was at moderate level and % drug release was increased. From this observation, formulation F11 was optimized as it provided desired lag time of 4.2\(\pm\)0.27 hours and least drug release of 72\(\pm\)0.09% for 8 hrs. The formulations were found to be physically compatible with excipients and stable.

Study of the Effect of Alfa-x to the Urea Formaldehyde Adhesive on Plywood

This study investigated the effect of adding Alfa-x to the of urea-formaldehyde (UF) adhesive. The content of free formaldehyde and the bonding specifications were examined. The three-layered plywood of poplar (Populus x eureamericana) and ekaba (Tetraberlinia bifoliolata) was prepared by adding alfa-x to adhesive mixtures in specified amounts. The content of free formaldehyde, withdrawal shear strength, and bending strength were studied in the experimental plywood. The strength specifications of plywood bonded with this resin were slightly reduced by adding the Alfa-x to the adhesive mixture. There was also a moderate decrease in the content of free formaldehyde.

Versatile Method To Reduce the Free Formaldehyde Content in Phenolic Resins for High-Temperature Applications

Versatile Method To Reduce the Free Formaldehyde Content in Phenolic Resins for High-Temperature Applications

Study of scavengers for free formaldehyde reduction in phenolic resins used in polychloroprene based contact adhesives

The objective of the study was to identify, analyze suitable scavengers for the free formaldehyde in phenolic resins used in polychloroprene based contact adhesives; as formaldehyde is a known CMR (carcinogenic, mutagenic, reprotoxic) agent. Phenolic resins used in the manufacture of adhesives inherently have formaldehyde which is trapped during synthesis. This study was carried out to reduce this to non-detectable levels of free formaldehyde. Sodium sulphite and sodium metabisulphite were used as scavengers to reduce free formaldehyde content. The reactions and mechanisms of the quenching was studied, to finalize the most suitable and feasible scavengers. Stages of addition of the identified scavenger during formulation of contact adhesives were done so that efficiency in reduction is maximum. Formulated adhesive was evaluated for applications and performance tests like peel strength and heat resistance in comparison with a control and it was found that scavenger addition (sodium sulphite and sodium metabisulphite) does not affect adhesives performance.

Engineering a pioneering melamine resin based on saccharide-derived aldehyde: Structure characterization and application for eco-leather production

Exploring new aldehydes with non-volatility and non-toxicity to replace formaldehyde (FA) for the fabrication of melamine resins (MRs) with eco-friendliness is a topical challenge worldwide. Herein, we report on a novel and facile way to synthesize an eco-friendly MR using a green crop-oriented saccharide-derived aldehyde (SDA) instead of FA. FTIR, NMR and XPS spectra demonstrated that a biomass-derived aldehyde bonded melamine resin (BMR) was synthesized. GPC test showed that the weight average molecular weight of BMR could be up to 4849 g/mol when the mole ratio between SDA and melamine (MA) was 1:1, which decreased as the SDA dosage increased. The application of BMR as a filling agent for leather processing indicated that BMR could improve the hydrothermal stability of filled leather and exhibited reasonable thickening capability. Meanwhile, the BMR-treated crust leather had higher mechanical strengths than melamine FA resin (MFR)-treated crust leather, and it contained almost no FA while the FA content of the MFR-treated crust leather was up to 86.4 mg/kg, indicating the favorable eco-friendliness of BMRs. This work presents a significant step forward for synthesizing environmentally-friendly BMR used in eco-leather production and other MR-involved industries.

Application of Urea Formaldehyde Raisin in Pavement Subgrade Stabilization at Hindon Barrage

Proper stabilization of foundation and subgrade is one of the major concerns in modern civil engineering projects. Development of modern infrastructure is causing harmful effect on environment by using chemicals. This situation has caused necessity to discover alternative techniques to achieve desired result without harming environment. Present paper studies use of urea formaldehyde raisin on chemical and physical stability of subgrade. Study was conducted by varying contents of urea formaldehyde by 1%, 3% and 5% and strength, ultimate bearing capacity and other relevant soil strength parameters were determined. At the end, cost benefits analysis was also conducted for the current method with respect to alternate subgrade stabilization techniques.

On the Development of Phenol-Formaldehyde Resins Using a New Type of Lignin Extracted from Pine Wood with a Levulinic-Acid Based Solvent.

Resole resins have many applications, especially for foam production. However, the use of phenol, a key ingredient in resoles, has serious environmental and economic disadvantages. In this work, lignin extracted from pine wood using a “green” solvent, levulinic acid, was used to partially replace the non-sustainable phenol. The physicochemical properties of this novel resin were compared with resins composed of different types of commercial lignins. All resins were optimized to keep their free formaldehyde content below 1 wt%, by carefully adjusting the pH of the mixture. Substitution of phenol with lignin generally increases the viscosity of the resins, which is further increased with the lignin mass fraction. The addition of lignin decreases the kinetics of gelification of the resin. The type and amount of lignin also affect the thermal stability of the resins. It was possible to obtain resins with higher thermal stability than the standard phenol-formaldehyde resins without lignin. This work provides new insights regarding the development of lignin-based resoles as a very promising sustainable alternative to petrol-based resins.

Fragrance oil microcapsules with low content of formaldehyde: Preparation and characterization

To reduce the residual formaldehyde content in melamine-formaldehyde (MF) microcapsules, glutaraldehyde was introduced to replace a portion of formaldehyde to prepare melamine-glutaraldehyde-formaldehyde (MGF) fragrance oil microcapsules via in-situ polymerization. MGF-lily oil microcapsules were obtained when the concentration of aldehyde groups provided by glutaraldehyde in the total aldehyde groups Cga∕Ca≤ 33.3 mol%. When Cga∕Ca≤ 9.5 mol%, the addition of glutaraldehyde reduced the residual formaldehyde content (235.05 ± 13.14 ppm to 21.79 ± 6.82 ppm) effectively without sacrificing the mechanical properties of microcapsules; it also improved the elasticity of microcapsules, in which Young’s modulus of MF shell was approximately 1.5 times to that of MGF shell. The approach was extended to encapsulate 2-hydroxy-3-(octanoyloxy)propyl decanoate (ODO), hexyl salicylate and lavender oil. All three fragrance oils were encapsulated successfully with low content of formaldehyde; however, the mechanical properties varied due to the difference on the hydrophobicity and viscosity of fragrance oil. This work provided an efficient and universal formaldehyde reduction method to encapsulate hydrophobic fragrance oil, which can not only reduce formaldehyde content but also maintain the mechanical properties and improve the elasticity of microcapsules, which has a potential application in consumer-friendly additives.

A novel resonance Rayleigh scattering assay for trace formaldehyde detection based on Ce-MOF probe and acetylacetone reaction

Formaldehyde (HCHO) is a widespread toxic pollutant, and the content of formaldehyde in food directly affects human health. Therefore, it is particularly important to establish and develop a rapid and accurate method for the determination of trace formaldehyde to ensure food safety. Metal-organic framework (MOF) has the characteristics of both organic and inorganic materials, which can be applied in various fields. What's more, Cerium (Ce) is the most abundant rare earth element. So far, it has no report about using Ce-MOF as a molecular probe of resonance Rayleigh scattering (RRS). The purpose of this research is to establish a new method for formaldehyde by combining the highly selective acetylacetone reaction with the sensitive RRS technology. When formaldehyde is added, acetylacetone reacts with it to form a complex (DDL), which acts as an accepter. There is a RRS-energy transfer (ET) between the DDL and Ce-MOF (act as the donor) because of spectral overlap. As a result, the RRS intensity of the Ce-MOF system decreased with formaldehyde concentration increase. So, Ce-MOF is used as a molecular probe of RRS to detect formaldehyde. In this study, the detection limit of formaldehyde was 0.063 µmol/L, and the determination range was 0.067–66.67 µmol/L. Compared with other methods, this method is simple in pretreatment and operation, and has a lower detection limit. Thus, a convenient detection of trace formaldehyde is realized.

ANALISA KANDUNGAN FORMALIN PADA PRODUK TAHU PUTIH DI KECAMATAN WONGSOREJO

Tofu is one source of protein from white soybeans by finely milling, boiling, and printing. The shelf life of tofu is very limited, under normal conditions (room temperature) the shelf life is on average 1-2 days, if more than this limit the taste of tofu will turn sour and give rise to a rotten aroma so it is not suitable for consumption. This makes foods such as tofu often added with chemicals or natural ingredients to make them last longer. One of the chemicals that is dangerous and often used is formalin, so there is a need for research on the content of formaldehyde in white tofu, especially in Wongsorejo District because white tofu is one of the foods that are often consumed by the community. This research was initiated by collecting tofu samples from four tofu factories in Wongsorejo District, namely Wongsorejo Village. The test was carried out qualitatively by using the Formalin Test Kit method. Based on the physical test and qualitative formalin test conducted on the four tofu samples taken from factories in the Districts of Wongsorejo, Sumberkencono, Bajulmati, and Sidodadi, it was found that all samples did not contain formalin.

Modified Natural Rubber as a Simple Chemical Sensor with Smartphone Detection for Formaldehyde Content in a Seafood Sample.

A new biodegradable platform-based sensor for formaldehyde assay is proposed. Natural rubber latex was modified to polylactic acid–chloroacetated natural rubber polymer blend sheets. The polymer blend sheet was grafted using a water-based system with amine monomers as a platform, with a spot exhibiting positive polarity for immobilizing with anionic dye (Acid Red 27). The sensor was exposed to formaldehyde. The color intensity of the dye on the sensor spot would decrease. Using a smartphone with image processing (via ImageJ program), the color intensity change (∆B) could be followed. A linear calibration, ∆B intensity = 0.365 [FA] + 6.988, R2 = 0.997, was obtained for 10–150 mM FA with LOD and LOQ at 3 and 10 mM, respectively (linear regression method). The precision was lower than 20% RSD. Application to real seafood samples was demonstrated. The ready-to-use sensor with the proposed method was cost-effective, was portable for on-site analysis, and demonstrated green chemical analysis.

Study of the aerogenic impact of formaldehyde on the health of child population

Introduction. Formaldehyde is a widespread environmental contaminant hazardous for human health; it belongs to the second hazard category for its inhalation exposure. Aerogenic inhalation exposure results in elevated risks of adverse effects on human health. Children are susceptible to such adverse effects produced by formaldehyde. Materials and methods. We performed chemical-analytical studies on formaldehyde contents in ambient air, inside pre-school children facilities and schools, and biological media of children living in a large industrial city (the test group) and a rural area (the reference group) in the Western Urals. Results. In the city, formaldehyde contents were 1.5 times higher in ambient air and 2.9 times higher inside pre-school children facilities and schools than in rural areas. Indoor air creates a more significant burden as per formaldehyde against ambient air, and its share is equal to 93% in the city and 87% in the rural area. The average group concentration of formaldehyde in blood was four times higher in the test group than the same parameter in the reference one. We also detected that formaldehyde contents were 7.6 times higher than the regional background level in the blood of children from the test group and 1.8 times higher in children from the reference group. We analyzed somatic morbidity as per nosologic categories and revealed that priority pathologies caused by exposure to formaldehyde were diagnosed 1.1-1.9 times more frequently in the test group than in the reference one (р<0.05). Regarding specific nosologies, priority nosologies were 1.8-9.7 times more frequent in the test group than in the reference group (р<0.05). We created statistically significant models showing dependence between a potential growth in morbidity with respiratory diseases, immune and nervous system diseases among children with elevated concentrations of free formaldehyde in the blood (R2=0.13-0.97; F=45.4-4,074; р≤0.001). Limitations. In the study, the possibility of an increase in the incidence of the child population, associated with the possible influence of factors not studied in this work, cannot be ruled out. However, the revealed relationships between the content of formaldehyde in the blood and the somatic status of children according to the criterion of the probability of an increase in the number of diseases from an increased content of formaldehyde in the blood may suggest one of the reasons for the increase in the frequency of respiratory diseases, disorders of the immune system, diseases of the blood and blood-forming organs in children under aerogenic exposure to formaldehyde. Conclusion. Having examined formaldehyde contents in air in the city and rural area, we established that toxicant concentrations were higher inside pre-school children facilities and schools in the city than in the rural area. High formaldehyde contents in the blood of children living in sizeable industrial cities occur predominantly due to aerogenic exposure to formaldehyde in indoor air and lead to more probable associated diseases of the respiratory, immune, and nervous systems.

Efficacy of urea solution reperfusion to a formalin-embalmed cadaver for surgical skills training.

Formaldehyde has been traditionally used for embalming human cadavers for gross anatomy education and surgical skills training. However, exposure to formaldehyde negatively affects human health. This study aimed to assess the efficacy of reperfusing urea solution to a formalin-embalmed cadaver for surgical skills training and then investigate the cadaver's tissue elasticity alteration after being soaked into the urea solution. Twelve surgeons evaluated the similarity of tissue characteristics between the cadaver (embalmed by formalin solution and reperfused by urea solution) and a living human body. Furthermore, the tissue formaldehyde content and mechanical properties of the formalin-fixated femoral skin and artery specimens with or without soaking into urea solution were measured. Results showed that the tactile assessment, skin incision, vessel ligation and suture, and decollement were better and more useful in the cadaver reperfused by urea solution than in the cadaver merely fixated by formalin solution. In the urea-reperfused cadaver, the volatilized, or tissue formaldehyde levels declined. The stiffness and Young's modulus of the femoral skin and artery were also lower in the specimen than in the mere formalin-fixated specimen. In conclusion, reperfusion of urea solution to the formalin-fixated cadaver makes anatomical education and surgical skills training more efficient with fewer requirements for cadaver management.

The Potential of Aloe Vera as Formalin Reductor in Formalyzed Javanese Chicken Meat

One of the hazardous materials that are often found during food control surveys is formalin. Formalin is used by irresponsible traders as a food preservative because it is cheap and easy to use. Therefore, efforts are needed to reduce the formalin content in food, one of which is by using natural ingredients such as aloe vera. Based on research, aloe vera contains saponins that can be used to reduce the formaldehyde content in food. This study aims to find out the concentration of aloe vera solution that can provide the largest reduction in formalin levels in samples of formalized chicken meat. The methods used in this study have three stages. The first stage is to soak the chicken meat in a 0.1% formalin solution for 1 hour then filtered to get samples of formalized chicken meat. The second stage is to soak samples of formalized chicken meat in a solution of aloe vera reduction with concentrations of 0, 30, 60, and 90% for 1 hour then filtered to get the filtrate. The third stage is to analyze the immersion filtrate using the UV-Vis Spectrophotometer to find out what the remaining formalin levels are in the chicken meat. The result of this study was that the higher the concentration of aloe vera solution, the greater the decrease in formalin content in the sample. The largest decrease in formalin content was obtained from soaking aloe vera solution with a concentration of 90%, which can reduce formalin by 29,87%.

Controlled preparation of nitrogen-doped hierarchical carbon cryogels derived from Phenolic-Based resin and their CO2 adsorption properties

Nitrogen-doped hierarchical carbon cryogels with good monolithic structure are synthesized from phenol (P), melamine (M), and formaldehyde (F) by sol-gel, freeze-drying, and carbonization process with different molar ratios of F/(P + M). The synthesized cryogels have the characteristics of cost-effective and abundant hierarchical pores. The pore structures, chemical properties, and CO2 adsorption performance of the prepared carbon cryogels are investigated. The results reveal that the PF carbon cryogel without N doping shows poor porosity characteristics, which leads to lower CO2 adsorption performance. For the N-doped PMF carbon cryogels, with the increase in the molar ratio of F/(P + M), the specific surface area and micropore volume decreases from 1160.6 to 874.1 m2/g and from 0.47 to 0.35 cm3/g, respectively, indicating that a lower formaldehyde content is conducive to the formation of more micropores and higher specific surface area. The carbon cryogel PMF2.0 (F/(P + M) = 2.0) exhibits a CO2 adsorption capacity as high as 5.79 mmol/g, and it also has a high CO2/N2 adsorption selectivity (13.43) and isosteric adsorption heat (33.06 kJ/mol). Thus, the PMF carbon cryogel exhibits immense potential as an adsorbent for CO2 capture, and its excellent performance is attributed to the synergistic effect of N doping and abundant micropores with appropriate size.

Anatomical and Morphological Features of the Leaves of Tilia Cordata Mill. As an Indicator of the Adaptive Capabilities of the Species to the Conditions of the Urban Environment

Study of the anatomical and morphological features of the photosynthetic apparatus of Tilia cordata Mill. showed that the volume of leaf mesophyll cells in an urbanized environment is higher than in natural plantings. The cells of the palisade mesophyll of the leaf have a greater variability of this indicator during the growing season as compared to the cells of the spongy mesophyll. Positive correlations of the indicator of the volume of cells of the palisade mesophyll with the indicator of the air pollution index, the content of phenol, formaldehyde, benzo(a)pyrene and negative correlations with the content of nitrogen dioxide were noted. The indicator of the volume of cells of the leaf spongy mesophyll positively correlates only with the indicator of the atmospheric pollution index and the content of formaldehyde.

A novel composite retanning system based on pH-responsive hydrogen bonding and hydrophobic interaction for cleaner leather processing

Aldehyde-tanned leather is one of the promising choices to avoid the widespread chrome pollution in leather industry. However, due to the lack of metal ions, the aldehyde-tanned leather faces a significant challenge of not being able to effectively fix traditional anionic retanning materials, which seriously affects the quality of aldehyde-tanned leather. Herein, a novel composite retanning system consisting of arylic resin (AR) and F6-600 (a nonionic fluorinated surfactant with poly(ethylene oxide) (PEO)) was constructed, which breaks through the dependence of conventional leather materials on metal ions in terms of fixation. The main acting mechanism is that at the final stage of retanning, after reducing the float pH, pH-responsive hydrogen bonding and hydrophobic interaction synergistically drive AR/F6-600 to self-assemble into bigger polymer composite aggregates, and then these aggregates are forced to deposit and fill in leather fiber gaps, thus obtaining more desirable retanning results. Furthermore, AR/F6-600 composite retanning system is eco-friendly. The AR/F6-600 retanned leather has lower free formaldehyde content, better biodegradability, and higher uptake rates for subsequent dye and fatliquoring agent, which can further eliminate the threat of formaldehyde to health, accelerate the degradation of waste leather in the nature, and reduce the chemical residual in wastewater, respectively. Consequently, this novel retanning system will benefit to satisfy evolving demands for related technologies toward cleaner leather production.

Al3+ coordinated chitosan hydrogel with ultrahigh water absorbency and environmental response

To fully utilize water, there is a great demand to develop eco-friendly materials with both ultra-high water absorbency and environmental response. In this study, the Al3+ coordinated chitosan (CIS-Al3+) hydrogels were prepared by formation of coordination bonds between Al3+ and the skeleton of CIS hydrogels. AlCl3 was used to provide coordination center, and the formaldehyde aqueous solution was chosen as crosslinker. The effect of Al3+ content and mass fraction of formaldehyde on gel formation, mechanical property and water storage capacity of CIS-Al3+ hydrogels was investigated deeply. The obtained CIS-Al3+ hydrogel can store more than 500% of its own weight of water without cracking, which demonstrates its super-absorbency. Besides, the CIS-Al3+ hydrogels can swell/shrink in response to the change of external stimuli such as temperature, pH and salinity. These outstanding properties, together with the low-cost raw materials, simple preparation method and biocompatible and biodegradable properties, enable CIS-Al3+ hydrogels to be applied as water storage materials in the agriculture field and pH-responsive materials in the future.

Fourier transform infra-red spectroscopy to determine formaldehyde to phenol ratio of phenol formaldehyde resole

A model has been proposed to determine the formaldehyde (F) to phenol (P) ratio [F/P] of resole with the help of Fourier transform infra-red spectroscopy. The study is based on the comparison of IR absorbance of the dominant peaks corresponding to the formaldehyde and phenol contents in the resin. This study can be of much use in adhesive coating industries to employ the F/P ratio as a quality tool as well as for competition resin benchmarking. It can also be utilized for understanding the kinetics of the reactions between phenol and formaldehyde. Detailed qualitative analyses of various resoles with different formulations have been discussed in this paper, which can be of potential help for the standard analysis of the commercial resins. The validation of results confirms that the most fitting model offers an error less than 7%. Interestingly, this model can also be applied with blends of different Phenol formaldehyde resoles.

INDICATIVE MEASUREMENTS OF FORMALDEHYDE CONTENT IN ATMOSPHERIC AIR OF MYKOLAEV

The article is devoted to the study of the possibility of using indicative measurements of formaldehyde (CH2O) content in the atmospheric air of the cities exposed to active vehicular transit flows. Motor transport is a fundamental factor of increased formaldehyde levels in the atmospheric air of such cities. Regional peculiarities affecting the increase of formaldehyde content and dispersion process in the surface layer of the atmosphere are added to the current situation, such as climatic and meteorological conditions, especially in summer, when high temperatures are combined with a lack of permanent winds; and the presence of a large unregulated automobile transit flow through the city. Within the framework of the Directive 2008/50/EU implementation into the national legislation of Ukraine it is necessary to introduce the ecological monitoring of the atmospheric air quality from the expansion of the fixed measurements by means of indicative measurements of air quality indices. The article raises the question of the consistency of the results of indicative and fixed measurements of formaldehyde content in the atmospheric air of cities. The purpose of the work is to study the peculiarities of the application of indicative measurements of formaldehyde content in the atmospheric air in the cities with heavy traffic, on the example of the city of Mykolaiv. The materials of the study are the results of measuring the formaldehyde content in the atmospheric air of the city by 7 stations of indicative measurements in Mykolaiv, as well as the results of determination of formaldehyde content at 4 stationary reference stations of atmospheric air monitoring in the city of Mykolaiv. It has been proved that there is a chronic excess of the maximum permissible concentrations of formaldehyde both during indicative measurements and at the fixed air monitoring stations in the airspace of the city of Mykolaiv. It has been shown that the results of indicative measurements of formaldehyde content in atmospheric air exceed in 1.5-1.6 times the corresponding values at fixed measurements, and the maximum values at fixed measurements exceed in 1.6-1.8 times the maximum values at indicative measurements. The necessity of calibration of indicative measurement stations in accordance with local conditions has been substantiated. The requirement of compulsory supplementing with indicative measurements of ecological monitoring of atmospheric air in the cities with intensive traffic flows has been shown.