• The Korean Journal of Food And Nutrition
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• v.29 no.1
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• pp.27-32
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• 2016

The purpose of this study was to measure concentrations of $K^+$, $Na^+$, $Cl^-$ by ionometer with check salt strip, simple salimeter and Ion-selective electrode (ISE) and compare the results of each mensuration; furthermore, the possibility of inferring the $Na^+$ concentration from $Cl^-$ concentration of urine and the impact of $K^+$ on the concentration of each ion was examined. The results showed that ISE determined $Na^+$ and $Cl^-$ concentrations in the urine are highly interrelated (R=0.9039); in addition, concentrations of $Cl^-$, measured with strip and ISE from urine are highly interrelated (R=0.9338). The concentration of $Na^+$ in urine, inferred by measuring $Cl^-$ concentration with strip, has a high relationship (R=0.8580) with the concentration of $Na^+$ in urine, measured by ISE. The results of our study will increase awareness of $Na^+$ intake and the utility of check salt strip, as well as the possibility of inferred $Na^+$ concentration from measures of $Cl^-$ concentration as a screening test for reducing sodium intake.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.122-122
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• 2017

Recently, environmental problems have become an area of growing interests. In-situ monitoring of water quality is fundamental to most environmental applications. The accurate measurement of nitrate concentrations is fundamental to understanding biogeochemistry in aquatic ecosystems. Several studies have reported that one of the most feasible methods to measure nitrate concentration is the use of Ion Selective-electrodes (ISEs). The ISE application to water monitoring has several advantages, such as direct measurement methodology, high sensitivity, wide measurement range, low cost, and portability. However, the ISE methods may yield inconsistent results where there was a difference in temperature between the calibration and measurement solutions, which is associated with the temperature dependence of ionic activity coefficients in solution. In this study, to investigate the potential of using the combination of a temperature sensor and nitrate ISEs for minimizing the effect of temperature on real-time nitrate sensing in natural water, a prototype of on-site water monitoring system was built, mainly consisting of a sensor chamber, an array of 3 ISEs, an waterproof temperature sensor, an automatic sampling system, and an arduino MCU board. The analog signals of ISEs were obtained using the second-order Sallen-key filter for performing voltage following, differential amplification, and low pass filtering. The performance test of the developed water nitrate sensing system was conducted in a monitoring station of drinking water located in Jeongseon, Kangwon. A temperature compensation method based on two-point normalization was proposed, which incorporated the determination of temperature coefficient values using regression equations relating solution temperature and electrode signal determined in our previous studies.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.10
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• pp.1372-1376
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• 2011

The content of Ca in milk exceeds the typical saturation level of Ca salts, which is necessary for neonate growth. This calcium is distributed between the casein micelles in the colloidal and aqueous phases. Information on the properties of calcium activity in the aqueous phase is limited compared with that on the properties of bound or sequestrated calcium. The objectives of this study were to evaluate the changes in calcium activity in fresh milk using an ion-selective electrode and to assess the relationship between calcium activity and milk production in hot season. Milk samples collected from 10 cows at the National Agricultural Research Center for Kyushu Okinawa Region in June to October (Min-Max: 7.2-$35.2^{\circ}C$, 24.3-100% RH) were analyzed on total calcium concentrations and calcium activity. We observed that the rectal temperature of the cows increased according to elevation of ambient temperature but that the pH of the collected milk ($6.61{\pm}0.01$ (Mean${\pm}$SEM)) was not significantly influenced by rectal and ambient temperature. Total calcium concentrations and calcium activity in fresh milk decreased in July (Min-Max: 21.1-$33.5^{\circ}C$, 48.9-100.0% RH) compared with the values after August (Min-Max: 18.1-$35.0^{\circ}C$, 26.5-96.2% RH) (p<0.05); however, there was no significant correlation between the two parameters. The ratio of calcium activity to total calcium concentration decreased after August compared with the values in June and July (p<0.05). The calcium activity in fresh milk was positively correlated with milk yield (r = 0.45, p<0.01) and negatively correlated with milk lactose content (r = -0.53, p<0.01). These results suggest that the calcium activity in milk could be affected by ambient temperature and might be associated with milking production in hot season.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.67-81
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• 1997

To determine the concentration and the physiologic role of metal components in blood plasma and seminal plasma in relation to male infertility, the concentrations of twelve metal components in blood plasma and seminal plasma including Na, Mg, K, Ca, Cr, Mn, Fe, Cu, Zn, Se, Cd and Pb were measured by atomic absorbance spectrophotometery or ion selective electrode analysis. Semen and blood samples were obtained from a total of 110 men including 70 male infertility patients, 20 vasectomized persons and 20 fertility proven volunteers visited to the Male Infertility Clinic of Pusan National University Hospital. The concentrations of Ca, Zn, Mg, Cr and Cd in control group were higher in seminal plasma than in blood plasma, and additionally Pb were higher in infertility group. The concentrations of all metal components revealed no significant difference according to patients' age, resident, occupation, sperm density, motility and hormone level in blood plasma, but some metal components including Ca, Mg, Cu, Mn, Cd and Pb revealed a significant difference according to each these parameters except patient's age in seminal plasma. The concentrations of Mn, Cd and Pb in the vasectomy persons were higher than in the infertility group III including testicular and epididymal factors, but not in blood plasma. We conclude that the quantitative changes of metal components in the seminal plasma may have effects on not only spermatogenesis and sperm function, but also contribute to diagnostic parameter according to organ specificity of the metal in the male reproduction.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.3
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• pp.105-112
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• 2011

More accurate evaluation of iodine consumption of Koreans can be made by measuring the urinary iodine excretion of people living in representative areas. The data about average iodine excretions by region, sex and age were gathered in order to suggest as a factor the criteria on the progress or prognosis of thyroid disease patients. This study was conducted on 3,000 subjects (2,000 Younggwang-gun residents and 1,000 Muan-gun residents) between July 2004 and August 2005. The data sampling was done based on stratified random sampling and the data were analyzed according to age (the subjects were divided into age groups, five years each) and sex of the subjects. Of the 3,000 subjects, a total of 1,592 people (1,174 in Younggwang-gun and 418 in Muan-gun) participated in this study, which used ISE (iodine ion selective electrode) to measure the concentration of iodine in urine. The 1,592 subjects are composed of 732 males and 860 females. The average urinary iodine excretion was $3.10{\pm}1.75mg/L$ (0.31~15.2 mg/L). The average iodine excretion of males was $3.09{\pm}1.61mg/L$ (0.42~15.2 mg/L) while it was $3.11{\pm}1.86mg/L$ (0.31~12.5 mg/L) among females, which represents no significant difference between males and females. However, the values were significantly higher than those of Europeans and Americans. There were statistically significant differences among the regions. When the data were analyzed according to age, females in their 40s were found to have a little less urinary iodine excretion and males had less and less iodine excretion as they get older. These results are deemed to have a statistically significant difference. This study was conducted on a large number of people (N=1,592) for the first time in Korea. If the data collected through this study can be regarded as the average urinary iodine excretion of Koreans, it is possible to conclude that the average iodine consumptions of Koreans are a lot more than Europeans and Americans. Thus, the effect of much iodine consumption should be studied further.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1153-1159
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• 2013

A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from $3{\times}10^{-7}$ to $1{\times}10^{-2}$ M and a lower detection limit (LDL) of $1{\times}10^{-7}$ M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.525-532
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• 1992

Fluorine-doped YBaS12TCuS13TOS17-xTFS1yT superconducting materials with y varing two orders of magnitude form 0.02 to 2.0 have been prepared by a sol-gel process by using metal nitrate salts, sodium hydroxide and sodium fluoride. Fluorine contents have been measured using an ion-selective electrode. All fluorine doped as reactant were found to be present in the resulted samples. From the observation of XRD it has been concluded that the samples with y 0.2 formed simply the single phase of perovskite structure, whereas those with y 0.5 yielded together some compounds such as BaFS12T, YFS13T and CuO in the resulted samples. The observation of solid state S019TF NMR has been carried out in order to check whether fluorine was actually incorporated into the lattice sites, and the experimental results revealed that the mole ratio of fluorine incorporated into the lattice sites of YBaS12TCuS13TOS17-xT was approximately 0.2 per mole of the compound. Also electrical resistivity measurement indicated that onset transition temperature has the tendency to increase slightly with increasing y in the dilute region as y 0.2.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.311-325
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• 2007

The concept of metal bioavailability, rather than total metal in soils, is increasingly becoming important for a thorough understanding of risk assessment and remediation. This is because bioavailable metals generally represented by the labile or soluble metal components existing as either free ions or soluble complexed ions are likely to be accessible to receptor organismsrather than heavy metals tightly bound on soil surface. Consequently, many researchers have investigated the bioavailability of metals in both soil and solution phases together with the key soil properties influencing bioavailability. In order to study bioavailability changes various techniques have been developed including chemical based extraction (weak salt solution extraction, chelate extraction, etc.) and speciation of metals using devices such as ion selective electrode (ISE) and diffusive gradient in the thin film (DGT). Changes in soil metal bioavailability typically occur through adsorption/desorption reactions of metal ions exchanged between soil solution and soil binding sites in response to changes in environment factors such as soil pH, organic matter (OM), dissolved organic carbon (DOC), low-molecular weight organic acids (LMWOAs), and index cations. Increasesin soil pH result in decreases in metal bioavailability through adsorption of metal ions on deprotonated binding sites. Organic matter may also decrease metal bioavailability by providing more negatively charged binding sites, and metal bioavailability can also be decreases as concentrations of DOC and LMWOAs increase as these both form strong chelate complexeswith metal ions in soil solution. The interaction of metal ions with these soil properties also varies depending on the soil and metal type.

• Analytical Science and Technology
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• v.5 no.3
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• pp.239-247
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• 1992

The complexations and selectivities of the 10 species of mono- and dimethylsubstituted anilinium ions with 18-crown-6 in methanol are examined at dropping mercury electrode. The stability constants of these complexes varies drastically due to the steric hindrance by the positions and numbers of methyl groups. And the analyses of the isomeric mixtures of methylanilinium, which are impossible to detect due to the overlapped peaks in normal conditions, were also accomplished by the additions of 18-crown-6 as the supporting complexing agent using the selective complexations by the steric hindrance effects. As results in case of the difference of stability, ${\Delta}log\;K$ were about 0.7~1.3, it was possible to confirm the existence of two species qualitatively. Otherwise when ${\Delta}log\;K$ were large than 1.6, the quantitative determinations of each species could be accomplished sucessfully. From these results it is deduced that the selective recongnition of the positions and numbers of methyl groups as the steric hindrance in anililniums by 18-crown-6 cause the large variation of the magnitudes of negative shift of reduction waves for guest ions in mixtures.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.474-479
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• 2012

Possibility of the selective removal of $Ca^{2+}$ ions from a mixed solution of $Na^{+}$ and $Ca^{2+}$ ions using membrane capacitive deionization (MCDI) was investigated. Adsorption equilibrium experiments were conducted to determine the selectivity of the CMX cation-exchange membrane toward $Ca^{2+}$ ions. In addition, desalination experiments for a mixed solution (5 meq/L NaCl + 2 meq/L $CaCl_{2}$) were performed using an MCDI cell. The adsorption equilibrium of CMX membrane showed that the equivalent fraction of $Ca^{2+}$ ions in the solution and the CMX membrane were 28.6 and 87.2%, respectively, which indicates the CMX membrane's high selectivity toward $Ca^{2+}$ ions. Desalination experiments were performed by applying a constant current to the MCDI cell until the cell potential reached 1.0 V. The amount of ions adsorbed did not significantly change as the applied current was changed. However, the equivalent fractions of $Ca^{2+}$ ions among the adsorbed ions were inversely proportional to the applied currents: 81.4, 78.4, 77.0, and 74.5% at 200, 300, 500, and $700\;A/m^{2}$ of applied current density, respectively. This result is attributed to the increased fraction of $Ca^{2+}$ ions adsorbed by the CMX membrane at lower applied current densities.