• Journal of the Korean Society of Food Science and Nutrition
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• v.4 no.1
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• pp.49-53
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• 1975

The effect of natural condiments on peptic hydrolysis of casein in vitro has been studied, peptic activity was determined by the colorimetric method using folin reagent. The obstructive compounds on colorimetry from hydrolyzates of casein were separated by gel filteration method using sephadex G-10 column and 0.05M NaCl. Zinger and red pepper $(0.1{\sim}1.0%)$ were found to have slightly supressing effect for protein digestive action of pepsin. But garlic, green onion and onion acted as synergist for protein digertive action of pepsin.

• Korean Journal of Microbiology
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• v.18 no.4
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• pp.155-160
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• 1980

Microorgansims utilizing anionic detergent as their carbon and sulfur sources were isolated from soils and sewages. Alkyl benzene sulfonate (Hiti) and sodium dodecyl sulfonate (SDS) were the detergent compound tested. Three of these isolated microorganisms were identified as Pseudomonas spp. and the others asKlbsiella, Enterobacter and Acinetobacter. Biodegradation rate of the detergents and growth rate of Acinetobacter Strain II-8, Pseudomonas strain H-3-1 and 554 among six isolated microorganisms were investigated with colorimetric, warburg manometric, and ultraviolet absorption analyses. By performance of 4 serial successive tranfer to new culture broth for the purpose of adaptation method, ABS and SDS could be degraded to far more than 40%-60% and 70%-75%, respectively. However the employment of nonadaptation method, ABS and SDS were degraded to 30%-45% and 45%-65%, respectively. In another words, detergents degradation ability was increased to a certain extent by successive transfer to the new minimal media. We would conclude that the development of adaptation was effective in the removal of recalcitrant compounds.

• Bulletin of the Korean Chemical Society
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• v.19 no.6
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• pp.689-695
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• 1998

Carbobenzoxy-alanyl-thiaarginine benzyl ester and carbobenzoxy-alanyl-thialysine benzyl ester were synthesized in solution. Kinetic studies were carried out using three different analytical methods, semi-classical method, progress curve analysis and competitive spectrophotometry. In competitive spectrophotometry, carbobenzoxy-valyl-glycyl-arginyl-p-nitroaniline was used as a detector. Kinetic constants such as $K_m$ and $V_{max}$ measured by competitive spectrophotometry are almost the same as those values measured by semi-classical method. Colorimetric Ellman's assays showed the thio-peptido mimetics to be a suitable substrates for trypsin. Kinetic studies with trypsin gave $K_m$ of 2.33 mM and $k_{cat}$ of $1.50{\times}10^5\;min^{-1}$ for carboxy-alanyl-thiaarginine benzyl ester and $K_m$ of $3.41{\times}10^{-3}\; Mm\; and\; k_{cat}\; of\; 520{\times}102\; min^{-1}$ for carbobenzoxy-alanyl-thialysine benzyl ester, respectively. Kinetic constants $(K_m=2.04{\times}10^{-2}\; mM, K_{cat}=4.42{\times}10^3 \;min^{-1})$ for natural substrate, carbobenzoxy-alanyl-lysine benzyl ester, were also evaluated by competitive spectrophotometry in order to compare the mode of binding on trypsin.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.177-186
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• 2022

In this study, newly improved Ferron assay test haved on timed spectrometry was used for the determination of hyolrolytic Al species presented in PACl coagulant. The color development reagent ferron was prepared by using conventional method and two newly developed methods. Then the ferron assay test was used to compare and analyze the distribution of Al(III) hydrolyzed species presented in the prepared PACl and alum. The preparing method of reagent A required an aging period of 7 days by adding a hydroxylamine hydroxide and a 1,10-phenanthroline monohydrate reagent, whereas the preparing method of reagent B was used as a coloring agent immediately without aging time. The regression analysis between UV absorbance and Al concentrations of conventional method and newly developed method of ferron reagents in low-concentration aluminum solutions and high-concentration aluminum solutions, showed the correlation coefficients of 0.999 or higher, as showing high correlations of conventional method and newly developed method. Applying Ferron assay test, Al species in the PACls and alum were classified as Ala(monomeric Al), Alb (polymeric Al), and Alc (colloidal and precipitated Al). Distribution of Al(III) hydrolyzed species according to the preparation of ferron colorimetric reagents was similar.

• Journal of Biosystems Engineering
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• v.41 no.2
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• pp.138-144
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• 2016

Purpose: Phosphorus is an essential element for water quality control. Excessive amounts of phosphorus causes algal bloom in water, which leads to eutrophication and a decline in water quality. It is necessary to maintain the optimum amount of phosphorus present. During the last decades, various studies have been conducted to determine phosphorus content in water. In this study, we present a comprehensive overview of colorimetric, electrochemical, fluorescence, microfluidic, and remote sensing technologies for the measurement of phosphorus in water, along with their working principles and limitations. Results: The colorimetric techniques determine the concentration of phosphorus through the use of color-generating reagents. This is specific to a single chemical species and inexpensive to use. The electrochemical techniques operate by using a reaction of the analyte of interest to generate an electrical signal that is proportional to the sample analyte concentration. They show a good linear output, good repeatability, and a high detection capacity. The fluorescence technique is a kind of spectroscopic analysis method. The particles in the sample are excited by irradiation at a specific wavelength, emitting radiation of a different wavelength. It is possible to use this for quantitative and qualitative analysis of the target analyte. The microfluidic techniques incorporate several features to control chemical reactions in a micro device of low sample volume and reagent consumption. They are cheap and rapid methods for the detection of phosphorus in water. The remote sensing technique analyzes the sample for the target analyte using an optical technique, but without direct contact. It can cover a wider area than the other techniques mentioned in this review. Conclusion: It is concluded that the sensing technologies reviewed in this study are promising for rapid detection of phosphorus in water. The measurement range and sensitivity of the sensors have been greatly improved recently.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.250.2-250.2
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• 2014

Currently, teeth whitening method which is applicable to dental surgery is that physician expertises give medical treatment to teeth directly dealed with a high concentration of hydrogen peroxide and carbamide peroxide. If hydrogen peroxide concentration is too high for treatment of maximized teeth whitening effect [1], it is harmful to the human body [2]. To the maximum effective and no harmful teeth whitening effect in a short period of time at home, we have observed the whitening effect using carbamide peroxide (15%) and a low-temperature atmospheric pressure plasma jet which is regulated by the Food and Drug Administration. The gas supplied conditions of the non-thermal atmospheric pressure plasma jet was with the humidified (0.6%) gas in nitrogen or air at gas flow rate of 1000 sccm. Also, the measurement of chemical species from the jet was carried out using the optical emission spectroscopy (OES), the evidence of increased reactive oxygen species compared to non-humidified plasma jet. We have found that the whitening effect of the plasma is very excellent through this experiment, when bovine teeth are treated in carbamide peroxide (15%) and water vapor (0.2 to 1%). The brightness of whitening teeth was increased up to 2 times longer in the CIE chromaticity coordinates. The colorimetric spectrometer (CM-3500d) can measure color degree of whitening effect.

• KSBB Journal
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• v.26 no.5
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• pp.471-476
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• 2011

Nowadays biodiesel (fatty acid methyl ester, FAME) has been becoming an important issue as a desired alternative of energy products because of non-toxic, biodegradable properties, and lower exhaust emissions. During esterification of fatty acids or transesterification of oils and fats with short chain alcohols by the alkali-catalyzed methanolysis, FAME and unrefined glycerol are generated. Quantification of glycerol as a by-product is important because of a determinant of biodiesel quality. However, the glycerol analysis by gas chromatography (GC) method has laborious works with sample preparation, long time and cost of sample analysis. Thus, there is a need to analyze glycerol more simply. Herein we demonstrate that the colorimetric assay for glycerol analysis conducted by UV-vis spectrophotometer at the wavelength 617 nm whose peak is maximum intensity of malachite green, resulting in the red-shift occurred proportionally as a function of glycerol amount. Thus, it is considered the solvent media for malachite green fading for biodiesel production: (1) water, (2) MeOH, and (3) EtOH. The resulting findings show that the peak intensity at 617 nm in glycerol-malachite green mixture had a relationship between glycerol concentration and degree of peak shift as increase in pure glycerol concentration approximately at pH 7.0. However, when it was measured the unrefined glycerol concentration by diluting and adjusting with water to buffer (pH 7.0), it was not observed the absorption peak at 617 nm because of impurities and OH ions. In case of glycerol from biodiesel production factories, glycerol concentration could be successfully measured.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.522-525
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• 2011

In this study, an established enzyme-linked immunosorbent assay and immuno-chromatography technique are combined to fabricate an immuno-strip sensor for the detection of S. aureus. The immuno-strip is manufactured by using four different functional membranes. The capture antibody is immobilized on the nitrocellulose membrane due to the high affinity and the capillary action through porous membranes induces a flow of sample. A colorimetric signal is appeared according to the enzyme reaction and is analyzed by the digital camera (qualitative analysis) and home-made image analysis software (quantitative analysis). Under the optimal conditions, samples with S. aureus in the range of $2.7{\times}10^4{\sim}2.7{\times}10^7CFU/mL$ can be detected by the colorimetric method within 30 min.

• Food Science of Animal Resources
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• v.43 no.1
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• pp.73-84
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• 2023

Campylobacteriosis is a common cause of gastrointestinal disease. In this study, we suggest a general strategy of applying gold nanoparticles (AuNPs) in colorimetric biosensors to detect Campylobacter in chicken carcass. Polymerase chain reaction (PCR) was utilized for the amplification of the target genes, and the thiolated PCR products were collected. Following the blending of colloid AuNPs with PCR products, the thiol bound to the surface of AuNPs, forming AuNP-PCR products. The PCR products had a sufficient negative charge, which enabled AuNPs to maintain a dispersed formation under electrostatic repulsion. This platform presented a color change as AuNPs aggregate. It did not need additional time and optimization of pH for PCR amplicons to adhere to the AuNPs. The specificity of AuNPs of modified primer pairs for mapA from Campylobacter jejuni and ceuE from Campylobacter coli was activated perfectly (C. jejuni, p-value: 0.0085; C. coli, p-value: 0.0239) when compared to Salmonella Enteritidis and Escherichia coli as non-Campylobacter species. Likewise, C. jejuni was successfully detected from artificially contaminated chicken carcass samples. According to the sensitivity test, at least 15 ng/μL of Campylobacter PCR products or 1×10³ CFU/mL of cells in the broth was needed for the detection using the optical method.

• Analytical Science and Technology
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• v.36 no.5
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• pp.216-223
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• 2023

Aluminium (Al) is one of the major elements in rocks and its concentration can be varied, depending on different rock types as well as sources. The present study aimed to propose an analytical method based on the UV-Vis as a cheap, simple, and common instrument equipped in most laboratories for Al quantification in rocks after the microwave assisted acid digestion. The aluminone and 8-hydroxyquinoline were investigated for the colorimetric assay. The results show that the 8-hydroxyquinoline reagent was more favorable in terms of the minimized affects of the potential interferences present in the digested solutions, i.e., Fe³⁺, Si⁴⁺ and F^-. The calibration curve was constructed from 0.10 mg/L to 3.00 mg/L with the goodness of linearity (R² = 0.9996). The limits of detection and quantification (LOD and LOQ) were estimated, i.e., 0.029 mg/L and 0.087 mg/L, respectively. The 8-hydroxyquinoline was applied to real rock samples, demonstrating favorable precision (RSD = 0.34 %-1.8 %) and no remarkable differences were found compared to the inductively coupled plasma-mass spectrometry (ICP-MS) as a reference measurement approach.