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Hak J.J.,KOTITI Testing and Research Institute | Kyu L.Y.,Yeungnam University | Woon M.S.,Kyonggi University | Yong C.N.,Kyonggi University | Yong C.N.,Environmental Analysis Center
Journal of the Korean Chemical Society

In order to develop a quantitation method for Perfluorooctanesulfonic acid(PFOS) contained in plastics that are mainly used in electric and electronic equipment, this study consisted of conducting method validations with LDPE samples using soxhlet solvent extraction and LC/MS. As a result, the limits of detection and quantitation (LOD, LOQ) were 2.58 μg/L and 7.82 μg/L, respectively. Additionally, the recovery was 96.102%. For the correlation coefficient of LC/MS, the r2 value was 0.9992 in the concentration range of 7.82.100 μg/L, which confirmed its linearity. Furthermore, for the standardization of the analysis method for PFOS in electric and electronic equipment to correspond to EU environmental regulations, we conducted a proficiency test with a number of domestic and international testing laboratories. Three of the ten testing laboratories that participated in the proficiency test submitted outliers. Accordingly, we examined the cause of the outliers using the 19F NMR, finding that the main cause was an error in the processing of the results for isomers in PFOS that existed in standard solutions and samples. Source

Lee S.K.,Konkuk University | Lee H.Y.,KOTITI Testing and Research Institute | Kim S.D.,Konkuk University
Fibers and Polymers

The dyeing and color fastness properties of levelling type acid dye, milling type acid dye, metal complex dye and reactive dye on ultrafine nylon, polyurethane fiber/film and their mixtures were investigated. Ultrafine nylon was dyed well with four types of dye at pH 3-6, but levelling type acid dye showed low washing fastness. Amine-rich polyurethane fiber exhibited enhanced dyeability due to amino groups which acted as dyeing sites, compared to regular polyurethane fiber. In simultaneous dyeing with milling type acid dye and metal complex dye, amine-rich polyurethane fiber absorbed more dye molecules than ultrafine nylon, the color difference between two fibers were apparent. Polyurethane-impregnated ultrafine nylon was also prepared and its build-up properties were determined. It was found that polyurethane whose soft segment was composed of polytetramethylene glycol (PTMG) and polypropylene glycol (PPG) showed improved dyeing property and subsequently high color strength. © 2013 The Korean Fiber Society and Springer Science+Business Media Dordrecht. Source

Shin J.-H.,Konkuk University | Park J.-M.,Konkuk University | Kim H.-J.,Konkuk University | Ahn J.-H.,KOTITI Testing and Research Institute | And 2 more authors.
Korean Journal for Food Science of Animal Resources

A rapid and simple analytical method, using liquid chromatography tandem mass spectrometry (LC-MS/MS), was developed to detect myo-inositol (MI) in infant formulas. For protein removal: acid hydrolysis and lipid removal through organic solvent extraction. The operating conditions for instrumental analysis were determined based on previously reported analogous methods that used LC-MS/MS. Quantitative analysis was used for the detection limit test, infant formula recovery test, and standard reference material (SRM) 1849a to verify the validity of our LC-MS/MS analytical method, which was developed to quantify MI. For validation, the results of our method were compared with the results of quantitative analyses of certified values. The test results showed that the limit of detection was 0.05 mg/L, the limit of quantitation was 0.17 mg/L, and the method detection limit was 17 mg/kg. The recovery test exhibited a recovery between 98.07-98.43% and a relative standard deviation between 1.93-2.74%. Therefore, the result values were good. Additionally, SRM 1849a was measured to have an MI content of 401.84 mg/kg and recovery of 98.25%, which is comparable to the median certified value of 409 mg/kg. From the aforementioned results, we judged that the instrumental analysis conditions and preparation method used in this study were valid. The rapid analytical method developed herein could be implemented in many laboratories that seek to save time and labor. © 2015 Korean Society for Food Science of Animal Recources. Source

Lee J.-H.,Konkuk University | Shin J.-H.,Konkuk University | Park J.-M.,Konkuk University | Kim H.-J.,Konkuk University | And 3 more authors.
Korean Journal for Food Science of Animal Resources

The development of a sample preparation method and optimization of the analytical instrumentation conditions were performed for the determination of the Vitamin B12 content in emulsified baby foods sold on the Korea market. After removal of the milk protein and fats by chloroform extraction and centrifugation, the Vitamin B12 was water extracted from the sample. Following filtration of the solution through a nylon filter, the water-soluble extract was purified by solid-phase extraction using a Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The solution eluted from the cartridge was dried under a stream of nitrogen gas and reconstituted with 1 mL of water. The sample solution was injected into an LC-MS/MS system after optimizing the mobile phase for Vitamin B12 detection. The calibration curve showed good linearity with the coefficient of correlation (r2) value of 0.9999. The limit of detection was 0.03 μg/ L and the limit of quantitation was 0.1 μg/L. The method of detection limit was 0.02 μg/kg. The Vitamin B12 recovery from a spiking test was 99.62% for infant formula and 99.46% for cereal-based baby food. The sample preparation method developed in this study would be appropriate for the rapid determination of the Vitamin B12 content in infant formula and baby foods with emulsified milk characteristics. The ability to obtain stable results more quickly and efficiently would also allow governments to exercise a more extensive quality control inspection and monitoring of products expected to contain Vitamin B12. This method could be implemented in laboratories that require time and labor saving. © 2015 Korean Society for Food Science of Animal Recources. Source

Kim J.W.,University of Suwon | Kim J.W.,KOTITI Testing and Research Institute | Kim Y.-M.,Frontier Laboratories Ltd. | Kim Y.-M.,Hallym University | And 7 more authors.
Journal of Chromatography A

For the quantitative analysis of phthalates in polymers, a thermal desorption (TD)-GC-MS method was compared with solvent extraction (SE)-GC-MS methods which require the long pretreatment procedures using large amount of harmful organic solvents. Calibration curves of TD-GC-MS showed good linearity (r2 > 0.9997) and low method detection limit (<30 mg/kg with 9.0% RSD). Quantification results for three kinds of test phthalate polymer samples (test PTPSs) showed an RSD below 7.4% and acceptable recoveries (78.3-117.4%) as in the standard method of International Electrotechnical Commission. Even in a sample with a high concentration of phthalates (PTPS #3), the method also showed good recovery with low RSD values. The TD-GC-MS results were comparable with those results by SE-GC-MS methods, indicating that TD-GC-MS method also can be used for the quantification of phthalates in polymers. The average recovery (92-103%) and RSD (<20%) values obtained from international inter-laboratory study for TD-GC-MS performed in six laboratories also indicated that TD-GC-MS can be used as an international standard method for the quantification of phthalates in polymers. © 2016 Elsevier B.V. Source

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