• Analytical Science and Technology
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• v.36 no.1
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• pp.53-58
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• 2023

2'-Hydroxy-3',4'-methylenedioxy-3,4,5-trimethoxychalcone (HMTC) is a newly synthesized chalcone that affects proliferation, cytotoxic potential and apoptosis in human leukemia cells. However, no validated determination method has been described so far for HMTC in biological samples. Thus, we developed a liquid chromatographic method using a tandem mass spectrometry to determine HMTC in rat plasma. Liquid-liquid extraction with ethyl acetate was used for the clean-up procedure. The analyte was separated on a reversedphase column with mobile phase of distilled water and acetonitrile (2:8, v/v, including 0.1 % formic acid). The ion transition of the precursor to the product ion was principally deprotonated ions [M-H]^- at m/z 356.8 → 327.2 for HMTC. This analytical method was successfully applied in pharmacokinetic study of HMTC after intravenous administration in rats.

• Analytical Science and Technology
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• v.20 no.1
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• pp.70-77
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• 2007

Twelve chlorophenols (CPs) were extracted by liquid phase microextraction (LPME) from the industrial waste-water and analyzed by GC/MS. To establish the optimal conditions, species of extraction solvent, sample amount, pH of sample, salting out effect, a number of sampling and plunger movement speed were investigated. As a result, the linearities of calibaration curves ranged from 0.9913 to 0.9999, while LODs and LOQs were from 0.05 to 10.0 ng/mL except 2,3,4,5-tetrachlorophenol and pentachlorophenol. Using this method, 4-chloro-3-methylphenol confirmed from waste water at the concentration of 784 ng/mL. The method can be applicable to detect chlorophenols from industrial waste-water.

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.465-474
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• 1986

The solvent extraction and cleanup processes for the simultaneous gas-liquid chromatographic determination of 11 kinds of organophosphorous pesticide residues in crops were investigated. The extracts dissolved with acetone were partitioned with petroleum ether after adding saturated NaCl solution. Evaporated the partitioning solvent, the residue was dissolved in methylene chloride and eluted through mixed adsorbent (1 : 2 : 4 of activated carbon, magnesia and diatomaceous earth) with methylene chloride as an eluent. The pesticides recovered were 82∼105% and the impurities were effectively removed.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.206-216
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• 1997

The purpose of this study was to determine the pore size distributions (PSDs) of polyester woven fabrics by using liquid extraction method. Three types of PSDs-percent PSD, PSD per unit area of sample and PSD per unit weight of sample-were evaluated. Plain, twill and satin polyester fabrics with various fabric counts were used as specimens. Results showed that the interyarn PSDs reflected the fabric characteristics such as the fabric count and the weave type and the intrayarn PSDs reflected the thread characteristics such as the number of fibers, the fiber diameter, the thread diameter and the thread twist. Of three types of PSDs, the PSD per unit area of sample best reflect fabric and thread characteritics. As the fabric count decreased, rc increased and interyarn pore volume increased. The PSDs were skewed to the small pore sizes and the pore volumes decreased in the order of plain> twill> satin. As the number of fibers, the fiber diameter and the thread twist decreased, the intrayarn pore volumes were increased.

• Journal of the Korean Chemical Society
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• v.31 no.3
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• pp.244-249
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• 1987

Liquid-solid extraction technique was applied to enrich volatile free acids (VFAs) from aqueous matrices. Chromosorb P was found to be an efficient solid sorbent. The unionized VFAs could be quantitatively recovered from the Chromosorb P column with ether while interfering watermiscible components were retained in the adsorbed water on the surface of Chromosorb P. The method of simple and efficient isolation-enrichment of VFAs, followed by the quantitative analysis employing stainless steel capillary column coated with Carbowax 20M containing phosphoric acid has been applied to the determination of VFAs in several aqueous samples.

• Environmental Analysis Health and Toxicology
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• v.18 no.3
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• pp.219-224
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• 2003

1,4-Dioxane is used as a solvent for lacquers, paints, varnish removers, dye baths and printing compositions. And it is also used for detergent preparations, cosmetics, deodorants and fumigants. A method is described for the determination of 1,4-dioxane in water samples by GC/MS. The extraction recoveries were studied for some solvents and solvent volume ratio were investigated using r-butyl methyl ether (MTBE). Optimum condition was obtained by the liquid-liquid extraction using the 10 mL of MTBE for 10 mL of water. Method detection limit of 1,4-dioxane in the 20 mL of water samples was 0.05 ng/mL. It could be determined in the range of 0.24∼240 ng/mL in treated water, and in the range of 0.69∼81.9 ng/mL in raw water, respectively. Risk assessments with 1,4-dioxane exposure by drinking water ingestion were carried out. Based on the results of analysis, chronic daily intake of 1,4-dioxane was 2.22${\times}$10$\^$-4/ mg/kg/day and excess cancer risk was calcu-lated to be 2.44${\times}$10$\^$-6/.

• YAKHAK HOEJI
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• v.46 no.2
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• pp.93-97
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• 2002

Methidathion is one of the organophosphorus pesticides commonly used for stamping out harmful pests in farming areas. This paper presents a fatality due to methidathion intoxication and describes the distribution of methidathion in postmortem blood and tissues obtained at autopsy. Qualitative identification of methidathion was achieved by TLC, GC and GC/MS, and quantitative analysis was performed by GC with thermionic specific detector (TSD). The analytes in postmortem specimens were extracted by liquid-liquid extraction (LLE) with ethylether. After the ethylether layer was evaporated, the residue was partitioned into hexane and acetonitrile, and the acetonitrile layer was used for analysis. Tissue specimens were homogenized with 4% perchloric acid and applied for LLE. After extraction, the extracts were reconstituted 100 $\mu\textrm{g}$ pyraclofos (IS, 100 $\mu\textrm{g}$/ml in methanol) for GC and GC/MS analysis. On analysis of postmortem specimens, methidathion was identified and quantitated. The methidathion concentrations were 2.0 $\mu$l/ml in blood, 24.4 $\mu\textrm{g}$/g in liver, 13.9 $\mu\textrm{g}$/g in lung, 21.8 $\mu\textrm{g}$/g in kidney, respectively.

• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.12-17
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• 2002

Simultaneous determination of nine water-soluble vitamins contained in multi-nutrient tablets was carried out by reversed phase high-performance liquid chromatography (RP-HPLC) equipped with analytical $C_{18}$ column and UV (270 nm) detector. Those standard vitamins were successfully separated within 23 minutes by gradient elution with solvent A (0.5 M potassium phosphate monobasic) and solvent B (0.25 M potassium phosphate monobasic-methanol, 1:1). Calibration curves showed good linealities with correlation coefficients (> 0.92) in tested ranged respectively. The detection limits were considered to be 2.1 ng for ascorbic acids 60 ng for Vit B$_{6}$ 3 ng for p-aminobenzoic acid, 9 ng for niacinamide, 9 ng for thiamin, 5.0 ng for folic acid and 1.5 ng for riboflavin at 0.05 a.u.f.s. Solid phase extraction through Sep-Pak (C$_{18}$ ) cartridge was successfully applied for purification of water soluble vitamins in commercial multi-nutrient tablets.ts.

• Environmental Engineering Research
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• v.24 no.1
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• pp.137-143
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• 2019

In this study, extraction, clean-up and instrumental analytical conditions were optimized for identifying and quantifying methyl-, chloromethylbenzi-, octyl- isothiazolinone (MIT, CMIT, BIT, OIT) and 3-iodo-2-propynyl butyl carbamate (IPBC), widely used biocidal active ingredients in human hygiene consumer products. Accuracy of the developed ultrasonic assisted extraction method followed by HPLC/MS analysis for four isothiazolinones and IPBC ranged between 60.4% and 113% in various types of consumer product samples. Method detection limits ranged 0.011-0.034 mg/kg for wet wipes, 0.57-1.5 mg/kg for liquid detergent and 0.58-1.6 mg/kg for powder detergent. Wet wipes, powder and liquid detergents collected from local market in Korea were analyzed to demonstrate the applicability of the developed method. Even after the regulation of those compounds in wet wipes, CMIT, MIT and IPBC were still frequently detected from complementary wet wipes without brand labels which were distributed to customers at local retail shops and restaurants. The maximum observed concentrations of MIT and CMIT found in those complementary wet wipes were 70.2 mg/kg and 11.3 mg/kg, respectively.

• Analytical Science and Technology
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• v.28 no.3
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• pp.228-235
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• 2015

The efficiency and applicability of the solid phase extraction disk method in a ²²⁶Ra analysis were examined by the gamma ray spectrometer (GRS) method using a Marinelli beaker and the liquid scintillation counter (LSC) method for groundwater. The recovered ²²⁶Ra, which was filtered by the solid phase extraction disk, was analyzed using gamma ray spectrometer The disks, which were pretreated for caulking the daughter nuclide, were sealed with polyethylene film. Distilled water was used for the blank value of the ²²⁶Ra activity. The recovery values of ²¹⁴Bi and ²¹⁴Pb in the solid phase extraction disk, which used ²²⁶Ra standard material, were 80% (295.21 Kev) and 104% (351.92 Kev), respectively, which were higher than 75% determined by the LSC. The injection of nitrogen gas into the measuring chamber reduced the interference values by about 10%. The detection limits of the ²²⁶Ra activity in a blank sample of 5 L were 0.17~0.40 pCi/L after 80,000 seconds of measuring time. The relationship of the ²²⁶Ra activity in the solid phase extraction disk method and in the LSC method in seven groundwater samples showed a correlation coefficient value 0.987, which implies the applicability of the solid phase extraction disk method. The results showed that ²²⁶Ra activity in groundwater using the solid phase extraction disk method has the following benefits: simple pretreatment, time saving, high recovery values, a low detection limit, and so on. Compared with the LSC method and the GRS method using the Marinelli beaker for the ²²⁶Ra analysis, the solid phase extraction disk method could be useful in groundwater samples with low levels of activities of radionuclides because the method is not restricted by the volume of the sample.