• Polymer(Korea)
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• v.35 no.1
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• pp.35-39
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• 2011

In this work, mesoporous carbons (CMK-3) were prepared by a conventional templating method using mesoporous silica (SBA-15) for using catalyst supports in polymer electrolyte membrane fuel cells (PEMFCs). The CMK-3 were chemically activated to obtain high surface area and small pore diameter with different potassium hydroxide (KOH) amounts, i.e., 0, 1, 3, and 4 g as an activating agent. And then Pt-Ru was deposited onto activated CMK-3 (K-CMK-3) by a chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto K-CMK-3 were determined by surface area and pore size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and inductive coupled plasma-mass spectrometry (ICP-MS). The electrochemical properties of Pt-Ru/K-CMK-3 catalysts were also analyzed by cyclic voltammetry (CV). From the results, the K3g-CMK-3 carbon supports activated with 3 g KOH showed the highest specific surface areas. In addition, the K3g-CMK-3 led to uniform dispersion of Pt-Ru onto K-CMK-3, resulted in the enhancement of elelctro-catalystic activity of Pt-Ru catalysts.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.283-287
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• 2014

This study determined the hazardous heavy metal content of mushrooms from markets in Seoul, Korea. One hundred and fifty mushroom samples were digested by the microwave method then the hazardous heavy metal (Pb, Cd, As, Cr, Ni and Hg) content was determined by the inductively coupled plasma-mass spectrometry (ICP-MS) and mercury analyzer. The average values of heavy metals in the samples were as follows: (mean [minimum-maximum], ${\mu}g/kg$); Pb 7.8 (1.9-30.0), Cd 45.3 (0.7-292.4), As 54.6 (24.2-229.3), Cr 42.6 (8.4-334.3), Ni 22.4 (up to 180.4), and Hg 8.9 (2.0-25.0). The contents of hazardous heavy metal in mushrooms were lower than those reported previously and also lower than the Provisional Tolerable Weekly Intake (PTWI) limit prescribed by the FAO/WHO. Thus, it could be suggested that the hazardous heavy metals levels in the mushrooms of retail market were adequately safe for consumption.

• Analytical Science and Technology
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• v.21 no.6
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• pp.480-486
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• 2008

This paper reports on the monitoring results of some heavy metals (Pb, Cd, As and Hg) in oriental mineral medicines. Levels of Pb, Cd and As were determined using the acid digestion method and ICP-MS. Hg levels were determined using the gold amalgamation method and Automatic mercury analyzer (AMA). The results indicated that, in the case of Pb, 25.81% (24 cases) of the samples were over MRL (5 mg/kg). Pb levels in Calamina, Pumex, and Cinnabaris exceeded MRL (5 mg/kg). In the case of Cd, 9.68% (17cases) of the samples were over MRL (0.3 mg/kg). Cd levels in Calamina, Pumex and Cinnabaris were exceeded MRL (0.3 mg/kg). In case of As, 24.73% (23 cases) of samples exceeded MRL (3 mg/kg). As levels in Calamina, Lithargyrum, Vermilionum, Cinnabaris and Chalcocitum exceeded MRL (3 mg/kg). In the case of Hg, it was shown that the 76.34% (78 cases) of the samples exceeded MRL (0.2 mg/kg). Hg levels in almost all the samples exceeded MRL (0.2 mg/kg). These results led us to recommend that the domestic commercial law to be legislated to ensure the quality estimation and safety of oriental mineral medicines.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.158-163
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• 2023

This study aimed to determine mercury (Hg), methylmercury (MeHg), and selenium (Se) levels in deep-sea fishes distributed in Gyeonggi-do, South Korea. Concentrations of Hg, MeHg, and Se were measured by using a mercury analyzer and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The average content (mg/kg) in the seafood samples was as follows: Hg, 0.7647 (0.0182-5.3620), MeHg, 0.0764 (0.0096-0.8750), and Se, 0.4728 (0.1075-3.5100). All the levels of MeHg were below the recommended standards of the Ministry of Food and Drug Safety i.e., <1.0 mg/kg. Recent studies have shown that Se prevents Hg toxicity. The average daily intake in humans was 3.3 ㎍/kg, which was lower than the recommended amount (50-200 ㎍/person/day). The weekly intake of Hg and MeHg was calculated to be 6.07% and 1.90%, respectively, of the provisional tolerable weekly intake (PTWI). This study showed that the weekly intake of Hg and MeHg from abyssal fish was less than the PTWI recommended by the Joint FAO/WHO expert committee on food additives. Therefore, the levels reported in this study are presumed to be adequately safe.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.323-343
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• 2018

This study defines the mineralogical, micro-textural and geochemical characteristics for the carbonate rocks and discusses the fluids that have affected the depositional environment of the Lower Makgol Formation in Seokgaejae section. Based on analysis of X-ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-ray Spectrometry (SEM-EDS), Electron Probe Micro Analyzer-Wavelength Dispersive X-ray Spectrometry (EPMA-WDS) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), carbonate miorofacies in the basal and the lower members of the Makgol Formation are distinguished and classified into four types. Type 1 dolomite (xenotopic interlocking texture) and Type 2 dolomite (idiotopic interlocking texture) have relatively high Mg/Ca ratio, flat REE pattern, low Fe and Mn. Extensively interlocking textures in these dolomites indicate constant supply of Mg ion from hypersaline brine. Type 3 and Type 4 dolomite (scattered and loosely-aggregated texture) have relatively moderate Mg/Ca ratio, MREE enriched pattern, low to high Fe and Mn. These partial dolomitization indicate limited supply of Mg ion under the influx of meteoric water with seawater. Also, the evidence of Fe-bearing minerals, recrystallization and relatively high Fe and Mn in Type 4 indicates the influence of secondary diagenetic fluids under suboxic conditions. Integrating geochemical data with mineralogical and micro-textural evidence, the discrepancy between the basal and the lower members of the Makgol Formation indicates different sedimentary environment. It suggest that hypersaline brine have an influence on the basal member, while mixing meteoric water with seawater have an effect on the lower member of the Makgol Formation.

• Analytical Science and Technology
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• v.25 no.3
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• pp.190-196
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• 2012

The human exposure of lead has usually detected the amount of lead in the whole blood, however, this method has a shortcoming to give the information on the short-term exposure to lead. In that sense, it is desirable to estimates the level of lead in plasma to draw the chronic bio-marker of lead exposure even though it is difficult to measure lead of several ng/L. An inductively coupled plasma-mass spectrometry (ICP-MS) method was developed for determining lead in plasma as the chronic bio-marker of lead of workers. To minimize the contamination of lead from the environment, we constructed class 1,000 clean room and compared the amount of floating dust before and after the operation of the clean room. The limit of detection (LOD) and the limit of quantification (LOQ) of lead in fetal bovine serum were 4.3 ng/L and 12.2 ng/L by NIOSH method (statistical calculation method) and 7.0 ng/L and 22.1 ng/L by signal/noise ratio, respectively. The accuracy was in a range of 92.3-101.3%, and the precision of the assay was less than 4% in the samples spiked in the concentration of 20 ng/L and 2,000 ng/L. The method was simple, reproducible and sensitive enough to permit reliable analysis of lead to the ng/L level in plasma and/or serum. The method was also useful for the biological monitoring of chronic exposure to lead.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.1038-1048
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• 2010

The purpose of this study was to investigate some heavy metals (Pb, Cd, Cr, Cu, Hg) in 52 commercial herbal pills used as general processed food, to identify weekly heavy metal intakes from herbal pills and to evaluate their potential health risks. The samples were digested with a microwave and determinations of heavy metal residues were carried out by inductively coupled plasma mass spectrometry (ICP-MS) and mercury analyzer. The mean values of heavy metal contents for herbal pills used as general processed food were Pb 0.421 (0.032~1.630), Cd 0.157 (0.011~0.515), Cr 1.033 (0.112~9.933), Cu 6.923 (1.333~16.755), Hg 0.010 (0.001~0.088) mg/kg. Lead contents of herba and cadmium of algae, herba were high (ANOVA-test, p<0.05). Levels of cadmium concentrations exceeding WHO reference values (0.3 mg/kg) were observed in 10 samples (4 species). The significant correlation was observed between Pb and Cd (r=0.633, p<0.01). The weekly intakes of Pb, Cd, Cr, Cu, Hg from herbal pills were 1.112 (0.072~5.088), 1.614 (0.029~9.257), 3.000 (0.252~23.690), 0.182 (0.008~1.235), 0.220 (0.000~0.420)%, respectively, as compared with the Provisional Tolerable Weekly Intake (PTWI) established by Joint FAO/WHO Expert Committee for food safety evaluation. Our data suggest regulations limiting heavy metals in herbal pills used as general processed food.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.1
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• pp.41-45
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• 2020

Objective: The objective of this study was to assess serum, hair, and urinary magnesium (Mg) levels in children with attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and both ASD and ADHD to reveal potential interactive effects. Methods: A total of 148 boys aged 4-9 years old were enrolled in this study, including 44 children with ADHD, 40 pediatric patients with ASD, 32 patients with both ADHD and ASD, as well as 32 healthy neurotypical children. Hair, serum, and urinary Mg levels were assessed using inductively-coupled plasma mass spectrometry (ICP-MS). Laboratory quality control was performed using certified reference materials of human hair, plasma, and urine. Results: No significant group difference in serum Mg levels was observed. Mg content in hair was found to be reduced in children with ADHD and ADHD+ASD compared to that in healthy controls by 11% and 15%, respectively. Urinary Mg levels in children with ADHD+ASD exceeded the control, ADHD, and ASD values by 51, 76, and 65%, respectively. Factorial analysis revealed significant contribution of ADHD to hair and urinary Mg levels. Multiple regression analysis demonstrated that hair and urinary Mg levels were considered as significant predictors of neurodevelopmental disorder complexity. Conclusion: We propose that impaired Mg status may provide a link between ADHD and ASD.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4258-4264
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• 2011

The total mercury concentration ($Hg_T$) of surface snow samples collected along a ~1500 km transect in east Queen Maud Land was determined using inductively coupled plasma sector field mass spectrometry to address the behavior of Hg on the Antarctic Plateau. Due to the volatile nature of mercury, measures were taken against Hg loss from standard solutions by choosing appropriate container material and stabilizing agents. Glass bottles with Teflon-lined caps were superior to Teflon and polyethylene containers in protecting against Hg loss, but addition of gold chloride ($AuCl_3$) or bromine chloride (BrCl) was necessary to ensure preservation of Hg. As Hg loss was also observed in snowmelt samples, our analysis may underestimate the actual amount of HgT in the snow. Even so, the measured HgT was still very low (< 0.4-10.8 pg $g^{-1}$, n = 44) without a signal of depositional enhancement accompanying photo-oxidation of atmospheric elemental mercury in austral midsummer. Moreover, the dynamic variation along the traverse implies spatial and temporal heterogeneity in its source processes.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3681-3686
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• 2014

In this study, we demonstrated selenium (Se) accumulation in Bifidobacterium longum strain (B. longum) and evaluated the effect of Se-enriched B. longum (Se-B. longum) on tumor growth and immune function in tumor-bearing mice. Analysis using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) revealed that more than 99% of Se in Se-B. longum was organic, the main component of which was selenomethionine (SeMet). In the in vivo experiments, tumor-bearing mice (n=8) were orally administrated with different doses of Se-B. longum alone or combined with cyclophosphamide (CTX). The results showed that the middle and high dose of Se-B. longum significantly inhibited tumor growth. When Se-B. longum and CTX were combined, the antitumor effect was significantly enhanced and the survival time of tumor-bearing mice (n=12) was prolonged. Furthermore, compared with CTX alone, the combination of Se-B. longum and CTX stimulated the activity of natural killer (NK) cells and T lymphocytes, increasing the levels of interleukin-2 (IL-2) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), and the leukocyte count of H22 tumor-bearing mice (n=12).