• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.12
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• pp.1583-1588
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• 2007

PC-camera based automatic titration was executed in the acidity analyses of vinegar, milk and Takju. The average hue value (Havg) of 144 pixels in the image of the sample solution being titrated was computed and followed up at regular time intervals during titration in order to detect the titration end point. The Havg increase of 5 degrees from the first Havg was regarded as reaching at the end point in the cases of vinegar and milk. The Havg increase set up to detect the end point was 70 degrees in the case of Takju. In the case of vinegar, the volume of added titrant (0.1 N NaOH) was $21.409{\pm}0.066mL$ in manual titration and $21.403{\pm}0.055mL$ in automatic titration (p=0.841). In the case of milk, it was $1.390{\pm}0.025mL$ in manual titration and $1.388{\pm}0.027mL$ in automatic titration (p=0.907). In the case of Takju, it was $4.738{\pm}0.028mL$ in manual titration and $4.752{\pm}0.037mL$ in automatic titration (p=0.518). The high p values suggested that there were good agreements between manual and automatic titration data in all three food samples. The automatic method proposed in this article was considered to be applicable not only to acidity titrations but also to most titrations in which the end points can be detected by color change.

• Analytical Science and Technology
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• v.12 no.3
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• pp.177-183
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• 1999

The determination method of free acid in spent U-Al nuclear fuel solutions by Gran plot titration was described. Effect of U(VI) and Al(III) on the alkalimetric titration of nitric acid was investigated in oxalate complexing media as well as in noncomplexing media. Positive biases were observed in both titration media when the end-point was estimated by the Gran plot method. It was found that the cause of the bias was U(VI) in the oxalate complexing media, but Al(III) in the noncomplexing media. The relative error was less than 1% in the titration of 0.1 M $HNO_3$ at a U(VI) : Al(III) : $H^+$ mole ratio of up to 2:12:1 as long as the pH of the oxalate titration media was sustained to be below 5.0 at the beginning of titration. The method was successfully applied to the determination of nitric acid in a solution of HANARO reactor fuel with U:Al mole ratio of 1:6.

• BMB Reports
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• v.35 no.3
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• pp.302-305
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• 2002

Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at $27^{\circ}C$ using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to $140\;{\mu}M$ by the microcalorimetry method, which agrees well with the value of $143\;{\mu}M$ for the inhibition constant that was obtained from the spectroscopy method.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.559-564
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• 2001

A method for calculating the main characteristics of a potentiometric titration curve in a carboxylic ion exchanger has been investigated. The potentiometric titration curves of simple electrolyte and ion exchangers (polyelectrolytes) showed a great difference between them. The acidity parameters of the ion exchangers, the thermodynamic constant (pK0), apparent equilibrium constant (K), and correction for the apparent equilibrium constant (b), were introduced and used to express the characteristics of the carboxylic ion exchanger. A characteristic equation related to the acidity parameters of the ion exchangers systems was derived. A fibrous carboxylic cation exchanger was used and potentiometric titration curves at different concentrations of the supporting electrolyte were obtained . To prove the validity of the characteristic equation, the concentration of the supporting electroyte was varied. In the present study, good agreement between the data points and the fitted curves was found in all the cases. The g (number of moles of alkali to 1 g of ion exchanger) of carboxylic ion exchanger was calculated from the concentration of supporting electrolyte (C), pH of the solution, and degree of neutralization of ion exchanger (x).

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.26-26
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• 1994

• The Journal of Korean Society of Virology
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• v.30 no.1
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• pp.61-70
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• 2000

Standard plaque assay using agarose-overlay has long been used for titration of many infectious virus particle. Plaque assay for the titration of varicella-zoster virus and its live vaccine requires three intermittent agarose overlay to visualize plaques. Overall procedure of the assay takes at least nine days from virus inoculation and microbe contamination including fungi is frequently accompanied during incubation period. We studied whether an immunofocus assay in conjunction with peroxidase-mediated immunohistochemical reaction may replace the standard plaque assay for the virus titration by comparing the two methods. A linear relationship was observed between number of foci and virus dilution. The number of foci in a given dilution of virus appeared a little higher than counted plaques formed in standard plaque assay. Independent titration results obtained from two assay methods for a given dilution of virus demonstrated a strong correlation ($r^2=0.99$). Foci of virus infected cells as revealed by the enzyme reaction could be counted either 4 days post-infection (p.i.) under low magnification (40X) microscopy, or 6 days p.i. by naked eye observation. Larger size of cell cuture plate, virus adsorption at $35^{\circ}C$, and 10% FBS in diluent appeared to be better conditions for the assay. Immunofocus assay will be an effective and dependable titration method for varicella-zoster virus and its live vaccine in place of the standard plaque assay in respect to accuracy, costs, and experimental convenience.

• Korean Journal of Clinical Laboratory Science
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• v.40 no.1
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• pp.18-25
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• 2008

In classical titrimetric analyses, the major concern is the concentration of titrant, usually the aqueous solution of hydrochloric acid or sodium hydroxide, that could be changed as time goes by and it is accompanied with the inaccuracy of the resulting data. And the statistical approach, the nonlinear regression analysis, which is a well-known statistical method, was introduced to determine the accurate concentration of the titrant and the exact value of parameters, $K_a$, r, $C_a$, $C_b$, for 0.01 M aqueous solutions of analytes, sodium pyruvate, sodium acetate, sodium bicarbonate, ammonium hydroxide, ammonium chloride and acetic acid at $25^{\circ}C$. We used Gauss-Newton method for the linearlization of the nonlinear titration system and the two-parameter fitting showed appreciable convergent data for the parameters of the analytes set with the various range of $K_a$ value.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.439-443
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• 1973

2-Mercaptothiazoline is very sensitive reagent for silver, which have been used for highly selective amperometric determination of silver. A method is described for the determination of micro-quantity of silver by amperometric titration with 2-mercaptothiazoline in ammonical solution. Direct titration of milligram amount of silver (0.05∼1.00mg) is possible in the presence of a number of foreign ions in ammonical solution containing ethylenediaminetetraacetic acid as masking agent under atmosphere. The interfering elements are gold and platinum. The milligram amounts of silver can be determined by the proposed method within an error ${\pm}$5%.

• Journal of Soil and Groundwater Environment
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• v.24 no.1
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• pp.10-16
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• 2019

Alkalinity is an essential parameter for understanding geochemical processes and calculating partial pressure of $CO_2$, dissolved inorganic carbon, and mineral saturation indices. The Gran Titration Method (GTM) is one of the most accurate methods for measuring the alkalinity in water samples. However, this method has not been widely employed in measuring groundwater alkalinity in Korea, probably due to inadequate and insufficient understanding of the method. In this regard, this article was prepared to introduce GTM and related know-hows learned from the authors' experiences in measuring alkalinity. This paper also introduces a MS Excel-based alkalinity calculator as a handy tool for GTM.

• Journal of Food Hygiene and Safety
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• v.20 no.2
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• pp.73-76
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• 2005

Center for Food Standard Evaluation, Korea Food and Drug AdministrationThis study was performed to compare analytical methods of nine synthetic food colors and six food color lakes in Korea, Japan, Joint FAO/WHO Expert Committee of Food Additives (JECFA), and USA. The experimental protocol of this study consists of three parts: titration method with titanium chloride, gravimetric and spectrophotometric method. To measure the total contents of food colors, Korea and Japan used titration method with titanium chloride, USA used the average value of titration method with titanium chloride equipped with Kipp generator and spectrophotometric method. Also, JECFA used titration method with titanium chloride equipped with KiPP generator. However, All the low organizations used gravimetric method to measure the total content of coloring matter on Food Red No.3. Although all organizations use various methods for analysis of coloring matters, total contents of coloring matter on food colors tested fell into the standard showing $85.08-96.40\%$ in synthetic food colors and $10.00-36.86\%$ in food color lakes.