• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.129-133
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• 2020

The concentration of remaining formaldehyde contained in waste liquid emitted from the process of urea-formaldehyde microcapsule synthesis was analyzed by gas chromatography-mass spectrometry (GC-MS). Three factors that can affect on the reaction of formaldehyde were selected including pH, ammonium chloride input and temperature. The effect of these factors on the concentration of remaining formaldehyde was studied. When ammonium chloride input was 0.025g, microcapsules could not be obtained or core substance leaked out because of weak shell, and therefore this reaction condition would be inadequate. It was confirmed that the concentration of remaining formaldehyde could be minimized when the microencapsulation was conducted at 70℃ and pH 2.5 by using a ammonium chloride input of 0.050g. This study can make contribution to UF microencapsulation in safer working environment.

• Korean Aquaculture
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• v.19 no.1
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• pp.34-42
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• 2007

양식 넙치 및 조피볼락을 이용하여 1시간 동안 포르말린(37% 포름알데히드) 100 mg/l, 300 mg/l 및 500 mg/l의 농도에서 약욕 처리한 후 근육 내에서의 포름알데히드 잔류 농도를 측정하였다. 또한 포르말린 농도 25 mg/l, 50 mg/l, 100 mg/l, 150 mg/l 및 200 mg/l의 에어레이션된 해수와 에어레이션이 공급되지 않은 해수에서의 포름알데히드의 손실율을 측정하였다. 1시간 500 mg/l의 포르말린으로 취급된 어류 근육의 포름알데히드 농도는 약욕(0 h 투여 중지) 후 즉시 분석된 대조구 조직의 포름알데히드 농도보다 유의적으로 높게 나타났다(p<0.05). 그러나 대조구 조직내 포름알데히드 농도는 포르말린에 노출 후 24, 48 및 72시간 지난 후 샘플된 어류조직에서의 농도와 유의적인 차이가 없었다(p>0.05). 25-200 mg/l의 포르말린이 포함된 해수의 포름알데히드는 $8{\sim}19$일 이내에 측정 가능한 아주 낮은 농도($0.05\;{\mu}g/ml$)로 되어지나, 그것의 분해는 에어레이션을 함으로서 $6{\sim}10$일 이내로 빨라졌다. 따라서 본 연구에서 밝혀진 것들은 어류양식산업에 있어서 포르말린의 적정 투여 중지 기간과의 결정에 필요한 자료를 제공한다고 생각된다.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.225-233
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• 2020

By the standards and specifications for hygiene products, three test methods for formaldehyde are specified for each item type of hygiene product. After derivatization using acetylacetone and 2,4-dinitrophenylhydrazine (2,4-DNPH), formaldehyde is analyzed by spectrophotometer and high-performance liquid chromatography (HPLC). Validation of the three test methods was performed on tissue, diaper lining and waterproof layer, and panty liner products. The results of linearity (R²), limit of detection (LOD), limit of quantification (LOQ), recovery rate (%) and reproducibility (%), showed that all three methods are suitable for analyzing formaldehyde in hygiene products. After derivatization with 2,4-DNPH and cetylacetone, formaldehyde was analyzed at 0, 3, 6, 9, 24 and 48 hours by HPLC. Formaldehyde derivatized with 2,4-DNPH showed no statistically significant change in formaldehyde peak area over time (P>0.05). But, acetylacetone-derivatizated formaldehyde showed a negative correlation coefficient (r) over time (P<0.01). We investigated the residual amounts of formaldehyde in 205 hygiene products distributed in Busan. Among 74 disposable diaper products tested, 73 had low concentrations of formaldehyde (0.13-29.87 mg/kg). Moreover, formaldehyde was not detected in any of 78 tissue, 27 disposable paper towel, 12 disposable dishcloth, 7 paper cup, one brand of paper straw and 6 disposable napkin products.

• Journal of the Korean Wood Science and Technology
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• v.35 no.3
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• pp.61-69
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• 2007

The building materials used for improving indoor air quality, the wood charcoal mixed with cement mortar or natural water paint were examined for their potential removing ability of formaldehyde. After the reaction of samples with formaldehyde in the glass flasks designed in our lab, the remaining formaldehyde was collected using DNPH (2,4-dinitrophenyl hydrazine) cartridges, and their concentration was determined using HPLC. From the results, it was found that the removing amount of formaldehyde per one gram sample containing 5, 10, or 15% of wood charcoal was more than three times compared to that of control (100% cement mortar or water paint). Their elimination percentages from the initial formaldehyde was about 80~90%. The experimental results for wood charcoal-water paint showed a similar trend with those of wood charcoal-cement mortar samples. Their elimination percentages from the initial formaldehyde was about 90%. It is proposed that formaldehyde is adsorbed on the adsorbed 'O' or 'OH' groups in the graphene layers formed through the re-arrangement of lignocellulose in the wood during the carbonization procedure.

• Journal of Food Hygiene and Safety
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• v.38 no.2
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• pp.46-54
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• 2023

In this study, we examined the residual amounts of formaldehyde in hygiene products to determine the safety of these products in Gyeonggi-do. Formaldehyde is among the harmful substances that may remain within certain hygiene products. On the basis of an analysis of formaldehyde in a total of 222 items (6 disposable paper straws, 9 disposable paper napkins, 21 toilet papers, 13 disposable dishcloths, 16 disposable paper towels, 32 wet wipes for food service restaurants, 25 disposable cotton swabs, and 100 disposable diapers), we detected traces in three wet wipes for food service restaurants (1.87 to 4.45 mg/kg), which is approximately 9% to 22% of the standard level (20 mg/kg). We established that all the hygiene products assessed in the study met the individual standards for formaldehyde, thereby confirming that safe products are being distributed. In the standards and specifications for hygiene products, the formaldehyde test method is regulated for application with respect to three categories based on the type of product. The samples used in this study were of types for which method 1 or method 2 is applied, and the limits of detection, limits of quantification, linearity, and recovery rates were reviewed to verify the validity of each test method. When method 2 was applied, we experienced interference when performing analysis at a wavelength of 412 nm, which was associated with the influence of impurities in some samples of disposable cotton swabs and disposable diapers. Consequently, in these cases, the results were compared after analysis using method 1. By comparing the results obtained using method 2 with those obtained using method 1, the latter of which were unaffected by the interference of impurities, we were able to detect formaldehyde at low concentrations. These findings accordingly highlight the necessity to standardize the formaldehyde test method for future analyses.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.452-455
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• 2003

마이크로캡슐화 기술은 심물질, 캡슐의 벽재재료 및 후가공과 관련한 응용기술로 구성되어 있으며, 심물질로서는 다양한 종류의 기능성 물질을 적용할 수 있다. 벽막재료 또한 목적하는 마이크로캡슐의 용도에 따라서 고분자 물질이나 무기재료 등 적합한 재료를 쓸 수 있다. 이러한 기술을 통하여 심물질 자체의 단점들 예를 들면 열안정성, 광안전성, 분산성, 등을 대폭 개선할 수 있고, 또한 이 심물질의 이용시 가공방법의 한계 등을 보완할 수 있으며, 특히 서방성을 목적으로하는 경우에 적당한 가공방법이라고 할 수 있다.(중략)

• Korean Journal of Microbiology
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• v.35 no.3
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• pp.237-241
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• 1999

Phenolic resin wastewater contained 41,000 mglI phenol, 2,800 mg/l fonualdehyde and various chlorinated phenolic compounds. Candida tropicalis PW-51 isolated [rom the natural enVlfooment was able to degrade 1,000 mg/l phenol in the presence of 100 mglI formaldehyde, but it took much time to degrade phenol with the increase of formaldehyde in phenolic resin wastewater. %en the phenolic resin wastewater was diluted to 1/40, the initial concentration of phenolic compounds (phenols) was 882 mglI and degraded to 81 mglI by C tfVpicalis PW-51 in batch culture. In a continuous biological treatment, the phenolic resin wastewater was diluted to 40 (745 mglI), 20 (1,356 mglI), or 10 (2,875 mglI) times. The removal efficiency of phenols in 1/40- and lI20-diluted phenolic resin wastewater was about 92%, but the phenols in 1!1O-diluted wastewater were not degraded. The remained phenols in wastewater were absorbed by a mixture of activated carbon and rice bran (1:1, v:v) in the process of absorption which was connected to the biological treatment. The total removal efficiency of phenols in 1!40~ and l/20-diluted phenolic resin wastewater was 99.9%.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.83-88
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• 2018

The purpose of this study was to investigate and evaluate the safety of the wet tissues. In this study, we analyzed sterilizing preservatives and the presence of harmful substances in 62 wet tissue samples in the market. The contents of preservatives, formaldehyde and methanol were analyzed by HPLC and headspace-GC, respectively. Cetylpyridinium chloride was detected as 7-13 ppm in 5 samples. Sodium benzoate was detected in 46 samples ranging from 200 ppm to 3500 ppm, and 9 ppm of methylparahydroxy benzoate was detected in 1 sample. Propylparahydroxy benzoate was not detected in any samples. 5 ppm of methylchloroisothiazolinone and 140 ppm of methylisothiazolinone were detected in 1 sample. Formaldehyde was detected as $0.0069-1.796{\mu}g/g$ in 59 samples. Methanol was detected ranging from 2 ppm to 51 ppm in 22 samples, and 4 samples showed more than 20 ppm of the legal limit. The pH of the wet tissues was 4.0 to 8.2. Continuous investigation and monitoring are necessary to ensure safe distribution of products.