• Analytical Science and Technology
• /
• v.14 no.1
• /
• pp.88-93
• /
• 2001

To measure the levels of dioxins in food selling at local markets, meat was analyzed by high resolution gas chromatography/high resolution ass spectrometry (HRGC/HRMS). The food samples were obtained from 5 large cities of Seoul, Chunchon, Daejon, Kwangju and Busan in Korea. All the samples were minced and extracted with Soxhlet extractor for 18 hours. After extraction, extracts were cleaned up by sulfuric acid impregnated silica gel, purified on a series of silica gel, alumina, carbon column chromatography and then analyzed by HRGC/HRMS. The contaminated levels were calculated as the TEQs by multiplying with the corresponding WHO-TEFs for each congeners. The overall recoveries were ranged from 80% to 153% and the limit of detection was about 0.01 ppt at S/N>3. The levels of PCDD/Fs for beef, pork and chicken were 0.018, 0.008 and <0.001 pgTEQ/g, respectively. In addition, the levels of non-ortho-co-planar PCBs for beef, pork and chicken were 0.008, 0.002 and 0.001 pgTEQ/g, respectively. Among food samples analyzed, chicken showed the lowest level of dioxin-like compounds. Regarding congener pattern, OCDD and PCB #77 were the highest contributing congeners.

• Analytical Science and Technology
• /
• v.12 no.6
• /
• pp.484-489
• /
• 1999

The extraction of trace amounts of Se in volcanic rock was investigated using the hydride generation method and atomic absorption spectrophotometry. The powdered rock, 1.0 g, was decomposed with the mixture of $HClO_4$, $HNO_3$ and HF in an acid digestion bomb at $140^{\circ}C$ for 2 hours. For the reduction of Se(VI) to Se(IV) in the solution, 10 mL of 6 M HCl and 0.2 mL of 1 M KBr were added to the solution and the mixture was heated for 30~45 minutes. $H_2Se$ was produced by adding 3% $NaBH_4$ as a strong reducing agent, extracted by nitrogen gas, and was absorbed twice into $KMnO_4$solution. The contents of Se in the solution were determined by generation/AAS. According to the proposed method, 1.0 ng or more of Se was quantitatively extracted and Se levels of 2.5 ng/g or more in rock samples could be determined. For example, Se in a rhyolite was determined with the precision of $19.5{\pm}1.3ng/g$(95% confidence, n=6).

• Korean Journal of Food Science and Technology
• /
• v.20 no.5
• /
• pp.659-665
• /
• 1988

The ${\alpha}_{s1}$-and ${\beta}$-casein were purified by DEAE-cellulose chromatography and digested with alkaline protease from Bacillus subtilis. Bitter fractions from the hydrolyzates were isolated using n-butanol extraction, Sephadex G-25 gel chromatography, and high performance liquid chromatography. Peptide mixtures were separated by reverse-phase octadecyl silica column with linear gradient of 0-80% acetonitrile containing 0.1% trifluoroacetic acid. Major peaks were combined from replicate chromatographies and the bitterness of each peak was evaluated. The bitter-tasting peaks were rechromatograpied until isolated peaks were obtained. Three different bitter peptides(BP-I, BP-II, BP-III) were obtained from the ${\alpha}_{s1}$-casein hydrolyzate. BP-I was eluted at 34% acetonitrile and BP-II, 35%, BP-III, 26%, respectively. Two bitter peptides(BP-IV, BP-V) were isolated from the ${\beta}-casein$ hydrolyzate: BP-IV was eluted at 40% acetonitrile and BP-V, 42%. BP-V was the most hydrophobic peptide in the five bitter peptides. However, BP-I and BP-II tasted more bitter than BP-IV and BP-V.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.4
• /
• pp.265-271
• /
• 2005

A rapid, selective and sensitive reversed-phase HPLC method for the determination of etodolac in human serum was developed, validated, and applied to the pharmacokinetic study of etodolac. Etodolac and internal standard, ibuprofen were extracted from human serum by liquid-liquid extraction with hexane/isopropanol (95:5, v/v) and analyzed on a Luna C18(2) column with the mobile phase of 1% aqueous acetic acid-acetonitrile (4:6, v/v). Detection wavelength of 227 nm and flow rate of 1.0 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^3$ factorial design using a fixed etodolac concentration $(1\;{\mu}g/mL)$ with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of $0.05-40\;{\mu}g/mL$ with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of serum was 0.05 ${\mu}g/mL$, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 92.00 to 110.00% for etodolac with overall precision (% C.V.) being 1.08-10.11%. The percent recovery for human serum was in the range of 76.73-115.30%. Stability studies showed that etodolac was stable during storage, or during the assay procedure in human serum. The peak area and retention time of etodolac were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of etodolac in human serum samples for the pharmacokinetic studies of orally administered Lodin XL tablet (400 mg as etodolac) at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.6
• /
• pp.423-429
• /
• 2005

A selective and sensitive reversed-phase HPLC method for the determination of fenoprofen in human serum was developed, validated, and applied to the pharmacokinetic study of fenoprofen calcium. Fenoprofen and internal standard, ketoprofen, were extracted from human serum by liquid-liquid extraction with diethyl ether and analyzed on a Luna C18(2) column with the mobile phase of acetonitrile-3 mM potassium dihydrogen phosphate (32:68, v/v, adjusted to pH 6.6 with phosphoric acid). Detection wavelength of 272 nm and flow rate of 0.25 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^{3}$ factorial design using a fixed fenoprofen concentration $(2\;{\mu}g/mL)$ with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of $0.05-100\;{\mu}g/mL$ with correlation coefficients greater than 0.999. The lower limit of quantification using 1 mL of serum was $0.05\;{\mu}g/mL$, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 92.27 to 109.20% for fenoprofen with overall precision (% C.V.) being 5.51-11.71 %. The relative mean recovery of fenoprofen for human serum was 81.7%. Stability (freeze-thaw, short and long-term) studies showed that fenoprofen was not stable during storage. But, extracted serum sample and stock solution were allowed to stand at ambient temperature for 12 hr prior to injection without affecting the quantification. The peak area and retention time of fenoprofen were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of fenoprofen in human serum samples for the pharmacokinetic studies of orally administered Fenopron tablet (600 mg as fenoprofen) at three different laboratories, demonstrating the suitability of the method.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.622-632
• /
• 2018

The aim of the present study was to evaluate of turmeric (Curcuma longa L.) on the physiological activities and oxidation inhibitory action. The effects of various solvents (distilled water DW, 70% ethanol and n-butanol) on the total phenolics content (TPC) of turmeric and their corresponding biological activity were studied. Bioactive compound of total saponin $7.506{\pm}0.349mg\;SE/g$ dry weight. Turmeric extracts yield were DW (17.11%), 70% ethanol (15.26%) and n-butanol (4.12%), respectively. Oxidation inhibitory action of the samples exhibited a dose-dependent increase. However, in the current study, none of the samples evaluated showed activity as strong as the BHA, ascorbic acid and EDTA. Results showed that extraction solvent had significant effects on TPC and oxidation inhibitory action (DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power and ferric reducing antioxidant power) of n-butanol. Turmeric exhibited the antioxidant properties, which suggests that the plant material could be used for further studies as a potential source for bioactive and natural antioxidant.

• Journal of Pharmaceutical Investigation
• /
• v.36 no.2
• /
• pp.89-95
• /
• 2006

A selective and sensitive reversed-phase HPLC method for the determination of pentoxifylline in human serum was developed, validated, and applied to the pharmacokinetic study of pentoxifylline. Pentoxifylline and internal standard, chloramphenicol, were extracted from the serum by liquid-liquid extraction with dichloromethane and analyzed on a Luna CI8(2) column with the mobile phase of acetonitrile-0.034 M phosphoric acid (25:75, v/v, adjusted to pH 4.0 with 10 M NaOH). Detection wavelength of 273 nm and flow rate of 0.8 mL/min were used. This method showed linear response over the concentration range of 10-500 ng/mL with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of the serum was 10 ng/mL, which was sensitive enough for pharmacokinetic studies of pentoxifylline. The overall accuracy of the quality control samples ranged from 89.3 to 92.7% for pentoxifylline with overall precision (% C.V.) being 4.1-9.2%. The relative mean recovery of pentoxifylline for human serum was 105.8%. Stability (stock solution, short and long-term) studies showed that pentoxifylline was not stable during storage. But three freeze-thaw cycles and extracted serum samples were stable. This method showed good ruggedness (within 15% C.V.) and was successfully applied for the analysis of pentoxifylline in human serum samples for the pharmacokinetic studies of orally administered $Trental^{\circledR}$ tablet (400 mg pentoxifylline), demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
• /
• v.37 no.4
• /
• pp.223-227
• /
• 2007

A rapid, simple and sensitive LC/MS/MS method for the determination of lercanidipine in human serum was validated and applied to the pharmacokinetic study of lercanidipine. Lercanidipine and internal standard, amlodipine, were extracted from human serum by liquid-liquid extraction with hexan-isoamyl alcohol (100: 1, v/v) and analyzed on a $Symmetry^{(R)}$ MS $C_{18}$ column with the mobile phase of acetonitrile-0.2% aqueous formic acid (70: 30, v/v). Using MS/MS with multiple reaction monitoring (MRM) mode, lercanidipine and amlodipine were detected without severe interferences from human serum matrix. Lercanidipine produced a protonated precursor ion ($[M+H]^+$) at m/z 612.3 and a corresponding product ion at m/z 280.0. Internal standard produced a protonated precursor ion ($[M+H]^+$]) at m/z 409.0 and a corresponding product ion at m/z 238.0. The ruggedness of this method was investigated using quality control (QC) samples. This method showed linear response over the concentration range of 0.05-20 ng/mL with correlation coefficient greater than 0.999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ng/mL, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the developed method ranged from 85.51 to 112.2% for lercanidipine with overall precision (% C.V.) being 3.56-13.1%. This method showed good ruggedness (within 15% C.V.) and was successfully applied for the analysis of lercanidipine in human serum samples for the pharmacokinetic studies, demonstrating the suitability of the method.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.6 no.3
• /
• pp.163-170
• /
• 2008

The reductive stripping of Np using a n-butyraldehyde (NBA) from loaded organic solution containing Np, which was oxidative-extracted in a system of a 30 % TBP/NDD-2M $HNO_3$ and O/A=2 containing 0.005 M $K_2Cr_2O_7$ as an oxidant of Np, was studied. The stripping yields of Np was increased with an increasing the NBA concentration, with a decreasing the nitric acid concentration of stripping solution and with a decreasing the reaction temperature. The apparent reductive stripping rate equation was shown by the following equation : $-d[Np]_{Org.}/dt$ = 1,524 exp(-2,906/T) $[NBA]^{0.91}\;[H^+]^{-0.92}[Np]_{Org.}$. At 1.04 M NBA and 2 M $NHO_3$, the stripping yield of Np and U was 70.1 %, and 7.1 %, respectively, and the separation factor of U over Np ($=D_U/D_{Mp}$) was about 30.4. Therefore, it was found that U and Np co-extracted in a system of TBP-$HNO_3$ could be effectively mutual-separated by the NBA.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.3
• /
• pp.441-451
• /
• 2000

Sludge produced from water treatment plants contains plenty of aluminum due to addition of coagulants, polyaluminum chloride(PACI) which has been widely used in most of water treatment plants. however. the whole of PACI is imported from other countries. In this research. the effective methods for recycling PACI from sludge of water treatment plants were developed and evaluated. Aluminum chloride hexahydrate($AlCl_3{\cdot}6H_2O$) was obtained by sparging HCl gas aluminum extracted from sludge using hydrochloric acid (HCI). This aluminum chloride hexahydrate was solidified by decomposition at $180^{\circ}C$. and dissolved in water to produce PACI. The optimum extraction rate was obtained at the condition of 10 minutes of reaction time. $105^{\circ}C$ of reaction temperature. 27.65%(W/W) of HCI concentration. The KS experiment proved that manufactured aluminum chloride hexahydrate was 98.7% degree and the recycled PACI coagulants agreed with the KS standard. The optimum temperature of decomposition was $180^{\circ}C$ and the basicity of the PACI was decided upon the extent of decomposition The compared experiments between purchased coagulant and manufactured coagulant presented that both coagulants had same performance for turbidity, DOC, $UV_{254}$ absorbance. and chlorophyll-a.