• Journal of Environmental Health Sciences
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• v.41 no.5
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• pp.289-298
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• 2015

Objectives: The method of analyzing urinary arsenic by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) is generally used because it shows relatively greater sensitivity, low detection limits, low blocking action, and is simple to operate. In this study, the results of analysis according to three pre-reductants commonly used in the FI-HG-AAS method were compared with each other. Methods: To analyze urinary arsenic, nineteen urine samples were collected from adults aged 43-79 years old without occupational arsenic exposure. Analysis equipment was FI-HG-AAS (AAnalyst 800/FIAS 400, Perkin- Elmer Inc., USA). The three pre-reductants were potassium iodide (KI/AA), C3H7NO2S (L-cysteine), and a mixture of KI/AA and L-cysteine (KI/AA&L-cysteine). Results: In the results of the analysis, the recovery rate of the method using KI/AA was 82.3%, 95.7% for Lcysteine, and 123.5% for KI/AA and L-cysteine combined. When compared with the results by use of high performance liquid chromatography inductively-coupled plasma mass spectrometry (HPLC-ICP-MS), the method using L-cysteine was the closest to those using HPLC-ICP-MS ($98.57{\mu}g/L$ for HPLC-ICP-MS; $74.96{\mu}g/L$ for L-cysteine; $69.23{\mu}g/L$ for KI/AA and L-cysteine; $13.06{\mu}g/L$ for KI/AA) and were significantly correlated (R2=0.882). In addition, they showed the lowest coefficient of variation in the results between two laboratories that applied the same method. Conclusion: The efficiency of hydride generation is considered highly important to the analysis of urinary arsenic via FI-HG-AAS. This study suggests that using L-cysteine as a pre-reductant may be suitable and the most rational among the FI-Hg-AAS methods using pre-reductants.

• Analytical Science and Technology
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• v.31 no.4
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• pp.171-178
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• 2018

Recently, for successful lactation, many breastfeeding mothers seek various products, including herbal medicine, dietary supplements, and prescribed medicines, to improve milk production. As demand for galactogogues grows, it is highly possible that pharmaceutical galactogogues may be adulterated with illegal products to maximize their efficacy. For continuous control and supervision of illegal products, we developed and validated a simple and sensitive LC-MS/MS method capable of simultaneously determining five galactogogues. Chromatographic separation was conducted using an Agilent Poroshell $120SB-C_{18}$ column with a mobile phase consisting of 20 mM ammonium formate (pH 5.4) and 100 % acetonitrile. The total run time was 13 min per analyte. The proposed method was performed according to the guidelines of the International Conference of Harmonization and it produced reliable results. This method showed high sensitivity and specificity, with a limit of detection (LOD) and limit of quantitation (LOQ) of 0.01-0.82 ng/mL and 0.02-2.45 ng/mL, respectively, for the solid- and liquid-type samples. Specificity was evaluated by analyzing matrix-blank samples spiked with the target compounds at LOQ levels, which provided a good separation of all peaks without interference. Additionally, the repeatability and intermediate precision were typically <15 %, whereas the recovery was 80-120 % of the values obtained using blank samples. Thus, we concluded that this method could be used for the identification and quantification of galactogogues in food or herbal products.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.519-525
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• 2019

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for health functional foods (dietary food supplements) to establish regulatory standards and specifications in Korea. In this regard, we are continuing our research on analytical method development for the items listed in the Korean Health Functional Food Codex. In this study, we have developed a sensitive and selective test method that could simultaneously separate and determine coenzyme Q10 based on liquid chromatographic-tandem mass spectrometry (LC-MS/MS). Calibration curves showed linearity with a correlation coefficient (R²) of > 0.999 and the limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 26.0 ㎍/L and 78.9 ㎍/L, respectively. The recovery results ranged between 98.6-107.0% at 3 different concentration levels with relative standard deviations (RSDs) less than 5%. The proposed analytical method was characterized with high resolution of the coenzyme Q10 and the assay was fully validated as well.

• Journal of Food Hygiene and Safety
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• v.21 no.2
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• pp.47-51
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• 2006

The formed acrylamide in many fried and baked starchy foods is in consequence of its formation during frying and preparation methods. Being acrylamide established to be a toxic substance, the implications to public health from amounts found in food are not clear. So this study was carried out to investigate the contents of acrylamide of French fries and snacks in addition to acrylamide formation in relation to water and lipid in foods. The raw materials of foods used in the experiments were wheat, potato, com and rice. The preparation of foods was modified in a little to raise the recovery ratio and contents of water and lipid were analyzed to the public food method. The contents of acrylamide were measured by the liquid chromatography tandem mass spectrometry. The average level of acrylamide produced in snacks is $236{\pm}322$ ppb and potato snacks came out the highest value at $521{\pm}403$ ppb in 104 snacks. The formation of acrylamide in fried food was found to depends on the composition of raw material not on water and lipid contents in food and not on storage period and temperature.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.4
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• pp.379-388
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and conducted for hydrogen production under the anaerobic fermentation of sucrose. Each bioreactor consisted of the column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed by the different hydraulic retention time(HRT), and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% of biogas throughout the operation. Hydrogen production rate was increased till $10.5\;L{\cdot}h^{-1}{\cdot}L^{-1}$ of bioreactor when influent sucrose concentrations and recycle rates were varied. At the same time, the hydrogen production rate with hydrophobic media application was higher than its hydrophilic media application. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate, butyrate and lactate. In order to run in the long term operation of both reactor filled with hydrophilic and hydrophobic media, biofilm accumulation on hydrophilic media and biogas produced should be controlled through some process such as periodical backwashing or gas-purging. Four sample were collected from each reactor on the opposite hydrogen production rate, and their bacterial communities were compared by terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR products generated using bacterial 16s rRNA gene primers (8f and 926r). It was expressed a marked difference in bacterial communities of both reactors. The trickling bed bioreactor with hydrophobic media demonstrates the feasibility of the process to produce hydrogen gas. A likely application of this reactor technology can be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• Analytical Science and Technology
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• v.17 no.5
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• pp.381-387
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• 2004

To characterize chemically a spent pressurized water reactor (PWR) fuel, an analytical method for trace amounts of tritium ($^3H$) in it has been established. Considering the effective management of radioactive wastes generated through the whole experimental process and the radiological safety for analysts, a separation condition under which $^{14}C$ and $^3H$ can be sequentially recovered from a single fuel sample was optimized using simulated spent PWR fuel dissolved solutions. $^{14}CO_2$ evolved during dissolution of the spent PWR fuels with nitric acid was trapped in an aliquot of 1.5 M NaOH. $^{129}I_2$ which was volatilized along with $^{14}CO_2$ was removed using a silver nitrate-impregnated silica gel absorbent. $^3H$ remaining in the fuel dissolved solution as $^3H_2O$ was selectively recovered by distillation. Its recovery yield was 97.9% with a relative standard deviation of 0.9% (n=3). $^3H$ in a spent PWR fuel with burnup value of 37,000 MWd/MtU was analyzed, reliability of this analytical method being evaluated by standard addition method.

• Analytical Science and Technology
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• v.28 no.2
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• pp.86-97
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• 2015

Recently, the consumption of dietary supplements has increased because of people’s greater interest in health. Unfortunately, the sales of dietary supplements containing unauthorized substances such as drugs have also increased. We developed a rapid, accurate method for the simultaneous determination of antihistamines using liquid chromatography tandem mass spectrometry with a multiple reaction monitoring mode. The limit of detection (LOD) and limit of quantification (LOQ) of the instrument used in this method were in the ranges 0.0003-0.3 and 0.0009-0.6 µg mL⁻¹, respectively. The linearity of the method was > 0.99. The precision levels of the method were 0.1-9.8% (intra-day) and 0.3-9.6% (inter-day), and the levels of accuracy of the method were 82.7-115.0% (intra-day) and 84.3-113.0% (inter-day). The mean of recovery of the method was in the range of 83.9-117.9% and the RSD of the stability was less than 5.9%.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.267-271
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• 2013

A survey of aflatoxin $B_1$ and ochratoxin A was conducted on dried red pepper and red pepper powder. Total number of 193 samples were collected from local markets in Incheon. The presence of aflatoxin $B_1$ and ochratoxin A was determined by high performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. The recovery rate of aflatoxin $B_1$ and ochratoxin A were more than 80% and the limits of quantification were 0.13 ${\mu}g/kg$ for aflatoxin $B_1$ and 0.30 ${\mu}g/kg$ for ochratoxin A. Aflatoxin $B_1$ was detected in 33 samples (17.1%) with a range of 0.14~9.67 ${\mu}g/kg$ and ochratoxin A was detected in 40 samples (20.7%) with a range of 0.31~3.31 ${\mu}g/kg$. These results show that the occurrence of aflatoxin $B_1$ and ochratoxin A in dried red pepper and red pepper powder tested in this study is low compared with the standard in Korea Food Code (10 ${\mu}g/kg$ as aflatoxin $B_1$ and 7 ${\mu}g/kg$ as ochratoxin A).

• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.259-268
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• 1993

When activity of peroxidase in auld Pnrqfonimn westermqni was monitored using o-dianisidine and $H_2O_2$ as substrates, its specific activity was 1.5 times higher In excretory-secretory product (ESP) than in crude extract. The one was purified by two purification steps of Sephacryl S-300 Superfine gel permeation and DEAE-Trisacryl M anion exchange chromatographies. Its activity increased 16.9 fold with 32.3% recovery. The enzyme was inhibited totally by 1 millimoles of dithiothreitol (DTT), 2-mercaptoethanol and azide. Molecular mass was 16 kDa in reducing SDS-polyacrylamide gel electrophoresis (PAGE) or 19 kDa in TSK-Blue gel filtration high performance liquid chromatography (HPLC). respectively. Special staining for peroxidase by diaminobenzidine on SDS-PAGE confirmed the activity. The peroxidase was less reactive to a paragonimiasis serum when observed by SDS-PAGE/immunoblot. In addition, specific activities of superoxide dismutase (SOD) and catalase were also identified in the ESP. High activities of these antioxidant enzymes in ESP indicate that they are parts of defense mechanisms against reactive oxygen intermediates from host.

• Journal of Nutrition and Health
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• v.32 no.6
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• pp.628-636
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• 1999

There is a marked increase in geriatric disease, especially liver disease, due to the continuous increase in alcohol and fat consumption. Since the fatty liver, induced by alcohol or fat, is basically from abnormalities in the lipid metabolism, it is possible that fatty acid binding protein(FABP) which is related to the fatty acid metabolism may also be abnormal in these livers. FABP is a small molecular weight protein family present in cytosol in high concentration. It has been proposed as a fatty acid transfer protein and as a binding protein responsible for controlling intracellular free fatty acid concentration. In this research, we have examined the relationship between liver FABP and fatty liver induced by alcohol or high cholesterol diet. Rats were fed one of either semipurified liquid diets; control diet containing 65% carbohydrate, 20% protein, and 15% fat or high cholesterol diet containing 1%(w/w) cholesterol or alcohol diet containing 37% of alcohol instead of carbohydrate. After 5 weeks of feeding period, all rats received commercial chow diet for 5 weeks to examine recovery effect. Liver and blood samples were collected at 0, 1, 3, 5 and 10 weeks to analyze lipid compositions. FABP was purified from liver cytosol and injected to rabbit to obtain antiserum. Liver FABP amount was determined by SDS-PAGE and western blotting methods. Fatty acid binding capacity was determined by binding of 14Cpalmitate with the delipidated liver cytosol. Consumption of alcohol increased serum cholesterol, triglyceride concentration and decreased HDL-cholesterol concentration after 5 weeks. Serum apolipoprotein B concentration increased after 3 weeks and LDL-cholesterol and apolipoprotein A concentration changed after 1 week. Liver cholesterol and triglyceride concentration increased after 3 weeks. Consumption of high cholesterol diet changed liver and serum lipid composition after 3 weeks. Swiching to normal diet for 5 weeks did not normalize most of lipid composition in serum and liver except serum and liver except serum cholesterol, triglyceride and liver cholesterol. Liver cytosol FABP content and the fatty acid binding capacity decreased dramatically after 1 week with alcohol consumption. This results indicate that FABP content changes before the changes before the changes of blood or liver lipid composition, suggesting changes of FABP may cause development of the fatty liver induced by alcohol and can be used as an index of detecting a early development of fatty liver.