• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.255-265
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• 2021

Objectives: The purpose of this study is to analyze the exposure characteristics of inorganic acids. Methods: We analyzed exposure data (n = 363,146) for six inorganic acids (hydrogen fluoride, hydrogen bromide, hydrogen chloride, phosphoric acid, nitric acid, and sulfuric acid) collected between 2017 and 2019 in South Korea. Measurement characteristics and exposure levels (ELs) were analyzed by inorganic acid, industry category, enterprise size, and measurement year. Results: Measurement percentage dominated in time-weighted average (TWA, 91%) compared to short term exposure limit (STEL) and Ceiling. Most of the measurements (79.7%) were collected from the manufacturing category of industry. Medians of ELs were mostly low (≤3% of the threshold limit), with the exception of sulfuric acid (4.6% of TWA and 10.5% of STEL). The percentages of exceeding 1% of the occupational exposure limits (OELs) in TWA were relatively high for sulfuric acid (35.8%) and hydrogen chloride (16.5%) compared to the other acids (4.2%-6.6%). In addition, the percentages of exceeding 1% of OELs in STEL or Ceiling were higher for sulfuric acid (22.9%), hydrogen chloride (12.3%), and nitric acid (8.2%) compared to the other acids (1.2%-1.9%). The small-sized enterprises showed higher ELs in TWA; contrarily, the large-sized enterprises had higher ELs in STEL or Ceiling. Conclusions: The measurement characteristics and ELs identified in this study could be useful for establishing safety and health policies for inorganic acids.

• Resources Recycling
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• v.26 no.1
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• pp.30-36
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• 2017

Leaching experiments of anode slime were performed with several inorganic acids (HCl, $HNO_3$ and $H_2SO_4$) together with thiourea and thiosulfate solution to recover gold and silver. Gold was not dissolved at all into these inorganic acids in the absence of any oxidizing agents. At the same concentration of inorganic acid, the leaching of percentage of Ag was the highest in the sulfuric acid solution. The leaching percentage of silver increased with the increase of HCl concentration owing to the formation of $AgCl_2{^-}$. Copper, nickel and zinc except tin was almost dissolved in these inorganic acids but no tin was dissolved in nitric acid solution. Most of Au and Ag were dissolved into the mixture of sulfuric acid and thiourea solution. Thiosulfate could dissolve some silver from the anode slime but no gold was dissolved by this agent.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.22-30
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• 2021

Objectives: The objectives of this study were to develop a quality control protocol of inorganic acids using ion chromatograph and to evaluate analytical proficiency of the legally designated agencies. Methods: This study prepared inorganic acid samples by injecting three anion certified solutions (chloride, nitrate, and sulfate) on the quartz filters. To investigate the storage stability and concentration consistency of the samples, 240 samples for each anion were tested at weeks 0, 2, 4, 8, 12, and 16 while storing at 4℃ and 25℃. To evaluate analytical proficiency, two separate testings were administrated for six skilled analysts and 46 analysts affiliated with legally designated agencies. Results: Average recoveries of the three ions after 16 weeks of storage were fairly high (over 95%). In addition, average recoveries (chloride = 97%, nitrate = 96%, and sulfate = 103%) after 16 weeks of storage at low temperate were relatively higher than those (94%, 93%, and 98%) at room temperature. The coefficients of variation (CV) for the three ions were less than 5% except for the sulfate sample at 5.56 ㎍ (CV = 12.4%). The average ratios of the concentration values analyzed by the legally designated agencies to the injected concentrations were close to 1. However, their CVs were relatively greater (chloride ≤ 49%, nitrate ≤ 14%, and sulfate ≤ 28%), which implies a need for quality control. Conclusions: The quality control protocol used in this study for the three inorganic acids can be utilized in the quality control for ion chromatography.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.161-165
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• 1982

In order to find out pertinent methods for the acceleration of browing during ginseng processing, various treatments were made or fresh ginseng (Panax Ginseng C.A. Meyer) with sugars, amino acids and inorganic nitrogenous compounds and the extent of browning was measured. Among sugars tested, maltose resulted in the greatest acceleration of browning followed in decreasing order by glucose and lactose, whereas pentoses, fructose, sucrose and raffinose had negligible effect. A marked browning occurred in ginseng treated with basic amino acids, while the extent of browning was not greatly increased when ginseng was treated with aliphatic amino acids, hydroxy amino acids, or acidic amino acids used in the experiment. Among treatments with sugar-amino acid mixture, a mixture of glucose with glutamic acid gave the greatest acceleration. The brown color intensity gradually increased with an increase in glucose concentration for up to 0.5M. inorganic nitrogenous compounds enhanced the browning in general, and the effect varied greatly with the different compounds.

• Journal of Soil and Groundwater Environment
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• v.27 no.5
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• pp.10-17
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• 2022

Inorganic acids such as HCl, HNO₃, and H₂SO₄ have been commonly applied to soil washing of heavy metals-contaminated soil due to their cost-effectiveness. However, implementing the 'Chemical Substance Control Act' requires off-site risk assessment of the chemicals used in the soil washing. Therefore, in this study, organic acids or Fe(III)-based washing agents were evaluated to replace commonly used inorganic acids. Ferric removed heavy metals via H⁺ generated by hydrolysis, which is similar to the HCl used in the control group. Oxalic acid and citric acid were effective to remove Cu, Zn, and Cd from soil. Organic acids could not remove Pb because they could form Pb-organic acid complexes with low solubility. Furthermore, Pb could be adsorbed onto the iron-organic acid complex on the soil surface. Ferric could remove exchangeable-carbonate, Fe-Mn hydroxide, and organic matter and sulfides bound heavy metals (F1, F2, and F3). Organic acids could remove the exchangeable-carbonate and Fe-Mn hydroxide bound metals (F1&F2). Therefore, this research shows that the fractionation of heavy metals in the soil and the properties of washing agents should be considered in the selection of agents in the process design.

• Economic and Environmental Geology
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• v.40 no.2 s.183
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• pp.141-151
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• 2007

This study was focused on iron removal from illite by L-ascorbic and oxalic acids. Iron has been shown as a secondary mineral such as iron oxides and hydroxides in illite ores. It is also known as a primary agent to degrade brightness index of the ores. Methods such as physical separation and chemical leaching with strong inorganic acids have been widely used to remove the iron from the ores. However, these methods are expensive and give rise to environmental problems. In this study, we examined an alternative method using solutions with different set of combination of sulfuric, hydrochloric, L-ascorbic, and oxalic acids. Compared to chemical treatments with only inorganic acids, our results demonstrate that an addition of L-ascorbic acid in inorganic acids results in decreasing both total concentrations of the inorganic acids and time for the treatments. The treatment with 0.15 M L-ascorbic acid and 0.25 M sulfuric acid in solution for 60 min significantly improved the brightness index from 42.4% to 74.4%. This improvement is similar to that of treatment with only 2.5 M sulfuric acid alone for 150 min. Mineralogical and chemical analyses were performed to compare the effect of acid leaching on illite powders. No obvious differences are observed in the mineralogical characteristics and particle size distributions of the samples. These results suggest that the treatment with the addition of L-ascorbic acid in sulfuric acid could effectively remove iron without modifying the physicochemical properties of illite under conditions used in this study.

• KSBB Journal
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• v.24 no.1
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• pp.75-79
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• 2009

The effect of inorganic, organic nitrogen sources and amino acids on the coenzyme $Q_{10}$ production and coenzyme $Q_{10}$ component ratio was investigated. Among the nine organic nitrogen sources, CSP showed a remarkable enhancing effect on the production of coenzyme $Q_{10}$. But this enhancement was not observed in medium containing Bacto peptone, tryptone, casamino acid and soybean meal. These differences on the production of coenzyme $Q_{10}$ may be due to differences in kinds and amounts of component amino acids and peptides in the various organic nitrogen sources tested. In the addition of inorganic nitrogens, only $(NH_4)_2SO_4$ increase the coenzyme $Q_{10}$ production by 2.0 times compare to the control group. The addition of L-tyrosine to the medium containing Bacto tryptone, was also determined to be crucial for the coenzyme $Q_{10}$ production. But phenylalanin and tryptophan, other aromatic amino acids, had no stimulatory effect on the coenzyme $Q_{10}$ production. These results show that the production and components ratio of coenzyme $Q_{10}$ was greatly affected by the kinds and the concentration of inorganic, organic nitrogen sources as well as amino acids.

• Food Science and Preservation
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• v.7 no.1
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• pp.108-112
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• 2000

Proximate composition , volatile compounds, free amino acids, fatty acids and inorganic compounds in leaf, stem and root of Houttyunia cordata Thunb cultivated from two different area, Bosung and Sunchon , were analyzed. Each part of Houttuynia cordata Thunb from both local area showed moisture contents of 80-84% and crude ash contents of 2.1 ∼2.8%. Crude fat and protein contents were less than 3 % showing slightly higher contents in leaf than in both stem and root . Twenty six volatile compunds were identified from the parts of the plant, the volatile contents were high in the oder of leaf, root and stem. Major volatile compounds were mostly derivatives of decanoic acid ; decanoic acid, 20 tridecanoie, decanal and dodecanoic acid. Of free amino acids in leaf asparagine was the highest, while in stem hydroxyproline, proline and arginine were the major free amino acids. Linoleic acid was the highest in the stem and root, and linolenic acid was highest in leaf. the major minerals of all parts were K, Ca. Mg, P, Fe, Zn and Cu, showing highest with K.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.4
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• pp.543-550
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• 2014

Fat and fatty acids in muscle and adipose tissues are among the major factors influencing meat quality particularly nutritional value and palatability. The present study was carried out to examine the effects of supplementing inorganic selenium (Se), iodine (I) and a combination of both on fatty acid compositions in serum, and supraspinatus (SS), longissimus lumborum (LL), and semitendinosus (ST) muscles in goats. Twenty-four, 7 to 8 months old, Kacang male goats with a mean live weight of $22.00{\pm}1.17kg$ were individually and randomly assigned into four groups of six animals each for 100 d of feeding prior to slaughter. The animals were offered the same concentrate (basal) diet as 1% of body weight with ad libitum amount of fresh guinea grass. The four groups were as follows: T1 (control) - basal diet without supplementation; T2 - basal diet with 0.6 mg Se/kg DM; T3 - basal diet with 0.6 mg I/kg DM; T4 - basal diet with combination of 0.6 mg Se/kg DM and 0.6 mg I/kg DM. The major fatty acids (FAs) detected in the serum were palmitic (C16:0), stearic (C18:0), oleic (C18:1n9) and linoleic (C18:2n-6), while the major FAs in the selected muscles were C16:0, C18:0 and C18:1n9 acids. The main polyunsaturated fatty acids (PUFA) detected in muscles and serum were (CI8:2n-6), linolenic acid (C18:3n-3), and arachidonic acid (C20:4n-6). No significant differences (p>0.05) were observed in the concentration of total saturated fatty acids (SFA) among the four groups. PUFA concentrations in the goats supplemented with Se (T2) were significantly higher (p<0.05) than the goats of the control group (T1). The PUFA: SFA ratio was significantly higher in the animals supplemented with dietary Se (T2) than those of control ones (T1). It is concluded that dietary supplementation of inorganic Se increased the unsaturated fatty acids in muscle. The supplementation of iodine with or without Se had negligible effects on muscle fatty acid content of Kacang crossbred male goats.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.351-358
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• 2012

To investigate the environmental adaptation and ecophysiological characteristics of Suaeda maritima and S. asparagoides under saline conditions, plant growth and density were analyzed according to environmental changes of habitats. The total ion content of soil decreased with time, which was caused by the predominance of exchangeable $Na^+$ and $Cl^-$ in the upper layers. The population of S. maritima was more densely distributed in the region with higher ion contents of $Cl^-$, $Mg^{2+}$, $K^+$ and $Na^+$ than the population of S. asparagoides. Both species were showed a decreased population density according to increases in plant growth. Under the conditions of a salt field, S. maritima and S. asparagoides contained high inorganic ions to maintain low water potential, but low water soluble carbohydrate contents. In the case of free amino acid, S. maritima showed an especially high proline content, and contained rather large amounts of free amino acids, whereas S. asparagoides did not. Both species showed high inorganic ion contents in the leaves, which might be a mechanism of avoiding the ionic toxicity by diluting the accumulated ionic concentration with a high ratio of water content to dry weight. This result suggests that S. maritima seems to adapt to saline conditions by accumulating proline in addition to inorganic ions. S. asparagoides seems to adapt by osmoregulation processes, using inorganic ions rather than free amino acids.