• Environmental Engineering Research
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• v.25 no.2
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• pp.197-204
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• 2020

A number of different nanoscale zero-valent iron (nZVI) materials have been prepared and compared depending on the desired properties for the particular application, but different physicochemical properties of this prepared nZVI make it difficult to universally compare and standardize them to the same scale. In this study, we aimed to demonstrate a simple microplate-based colorimetric assay using 4-chlorophenol as an indicator with respect to the remediation of real treatment targets, such as trichloroethylene (TCE), 1,1,1-trichloroethane (TCA), and atrazine. Effect of nickel contents on 4-chlorophenol reduction was successfully investigated by the miniaturized colorimetric assay. In the same manner, the effect of nickel contents on dehalogenation of TCE, TCA, and atrazine was investigated and the pseudo-first-order kinetic constants were compared with the results for 4-chlorophenol. The similar pattern could be observed between 4-chlorophenol reduction obtained by colorimetric assay and TCE, TCA, atrazine reduction obtained by a traditional chromatographic method. The reaction kinetics does not match perfectly, but the degree of reaction can be estimated. Therefore, the colorimetric assay can be a useful and simple screening tool to determine nZVI reactivity toward halogenated organics before it is applied to a particular remediation site.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1117-1123
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• 2019

Control of pine wilt disease, which is caused by pine wilt nematode Bursaphelenchus xylophilus, is heavily dependent on the use of chemicals such as abamectin. Although such chemicals are highly effective, demands for alternatives that are derived preferentially from natural sources, are increasing out of environmental concerns. One of the challenges to discovery of alternative control agents is lack of fast and efficient screening method that can be used in a high-throughput manner. Here we described the development of colorimetric assay for the rapid and accurate screening of candidate nematicidal compounds/biologics targeting B. xylophilus. Contrary to the conventional method, which relies on laborious visual inspection and counting of nematode population under microscope, our method utilizes a redox dye that changes its color in response to metabolic activity of nematode population in a given sample. In this work, we optimized parameters of our colorimetric assay including number of nematodes and amount of redox dye, and tested applicability of our assay for screening of chemicals and biologics. We demonstrated that our colorimetric assay can be applied to rapid and accurate quantification of nematode viability/mortality in a nematode population treated with candidate chemicals/biologics. Application of our method would facilitate high-throughput endeavors aiming at finding environment-friendly control agents for deadly disease of pine trees.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1438-1442
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• 2003

A method for the determination of nitrogen in ruminant feedstuffs, products and excreta (e.g. milk and urine) using a spectrophotometer is developed, where samples processed for P determination are also used to determine N. Samples are digested with sulphuric acid and subsequently with hydrogen peroxide in Kjeldahl tubes. Digested solutions along with phenol and buffered alkaline hypochlorite reagents are incubated in a water bath at $37^{\circ}C$ for 30 min and presented in the spectrophotometer. The spectrophotometer set at 625 nm measures the concentration of N of each sample. Nitrogen in 261 of the samples was also determined by the classical Kjeldahl method in order to develop a relationship between N determined by the Kjeldahl method (Y) and the colorimetric method (X). The mean value of Y was as high as that of X (0.92 vs. 0.96; p>0.05). The colorimetric method predicted Kjeldahl N highly significantly (Y=0.985X-0.024, $R^2=0.993$, p<0.001; or more simply Y=0.974X, $R^2=0.993$, p<0.001). An analysis of regression found no difference (p>0.05; both t-test and F-test) between colorimetric (0.96% N) and adjusted (0.96% N) N. In comparison with the Kjeldahl method, the analytical capacity of N by colorimetric method increases greatly, where 200-300 determinations of N are possible in a working day. In addition, the system provides an opportunity to use not only the same digested solution for both N and P determination of a particular sample, but also uses the same spectrophotometer to assay both N and P. Therefore, the system may be attractive in situations where both elements of a sample are to be determined. In conclusion, the speed of N determination, low cost, efficient use of labour, time and reagents, fewer items of equipment, and the reduction of environmental pollution by reducing effluent and toxic elements are the advantages of this method of N determination.

• YAKHAK HOEJI
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• v.21 no.1
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• pp.27-29
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• 1977

Amoxicillin formed blue color when heated with phophomolybdic acid in adequate condition, and the color showed maximal absorbance at 760nm. Effect of pH, concentration of phosphomolybdic acid and reating time were studied. And a new colorimetric method of determination of amoxicillin was developed.

• KSBB Journal
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• v.23 no.6
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• pp.484-488
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• 2008

Chlorinated phenols are widely used by the chemical industry as intermediate products in synthesis and previously were frequently applied to various industry fields. Peroxidases catalyze the peroxide-dependent oxidation of a range of inorganic and organic compounds. Peroxidase was shown to mineralize a variety of recalcitrant aromatic compounds and to oxidize a number of polycyclic aromatic and phenolic compounds. Among monomeric phenolic and nonphenolic compounds, peroxidase is known to oxidize its compounds. In this study, a colorimetric assay was developed to quantitatively evaluate the peroxidase activity for rapid screening. Color products of different intensity were developed proportionally to the peroxidase activity on agar plate and 96-well plate. This method correlates well with the RP-HPLC result. Using this screening method, 12 colonies of strain was screened which survived at high concentration of 2,4-DCP (1000 ppm) and with peroxidase activity for the $7^{th}$ round screening step on agar plate. These strains were utilized 2,4-DCP as a sole carbon source and produced peroxidase. After the screening test, four of the bacteria have significant better effect of COD removal on dye waste-water. COD removal of these was from 44% to 61%, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.59-64
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• 2003

To Photochoromic lens light irradiation side darkening status and fading status photo-transmittance decrease. If remove light irradiation, get into fading state and photo-transmittance has reversibility process that get back originally in state. Get CIE $L^*a^*b^*$ relationship colorimetric using darkening in Photochoromic lens and at fading process. Photochromism's spectrophotometer that produce itself. Darkening and fading state colorimetric ($a^*-b^*$) linear be curvy, and is gradidnt of (-) value. And change lineally. The colorimetric transfer amount is Blue ${\rightarrow}$ Yellow, Red ${\rightarrow}$ Green form. Colorimetric is low $b^*$ value than darkning state in fading state, and Photochromism's coodination transfer moves on the contrary with darkning state, photochoromism relationship estimation method about photochoromic lens can use by colorimetric difference about darkening and fading.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.15 no.1
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• pp.37-50
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• 1989

The in Vitro chemosensitivity of fibroblast cell strains was determined using a semiautomated tetrazolium-based colorimetric assay(MTT assay) to 16 cosmetic materials. This assay is useful method to evaluate toxic effects of the chemicals. From assay results, we determined that the preservatives are more toxic than moisteurizers. The chemicals in the same group have a different toxicity. That is, in preservatives, Germall -115 is more toxic than Danisol -M, -p, and in surfactant sodium laurel sulfate than Myrj 52, and in moisteurizers, 1, 3-butylene glycol is more safe than the others. When the results from this assay for preservatives were compared with patch test results, good correlation was observed. Forthemore, this assay method can be used together with Patch test for the evaluation of the chemical toxicity, particularly in cosmetic field.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.127-133
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• 1979

A simple and rapid colorimetric method for determination of panaxadiol and , panaxadiol was developed. 1. After heating with 60% perchloric acid, panaxadiol and panaxadiol yielded red.purple color with absorption maximum at 540 nm and 538 nm, respectively. 2. The maximum colors of the Panaxadiol and panaxadiol were reached when the algycones were treated at 6$0^{\circ}C$, 5 minutes or 7$0^{\circ}C$ 3 minutes. 3. The absorbance varied linearly with the amount of aglycone in the reaction mixture. And the colorimetric method was sensitive to about 10$\mu\textrm{g}$ of aglycone in 5.5ml of the reaction mixture. 4. The color was stable for about a week at 4$^{\circ}C$. 5. $\beta$-Sitosterol, oleanolic acid and cholesterol were not yielded red color by treatment with 60% perchloric acid under the conditions described.

• BMB Reports
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• v.36 no.4
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• pp.417-420
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• 2003

The present work describes a colorimetric microplate assay for lipase activity based on the reaction between 5,5'-dithiobis(2-nitro benzoic acid) (DTNB) and the hydrolysis product of 2,3-dimercapto-1-propanol tributyrate (DMPTB). Reaction mixtures containing DTNB, DMPTB, and lipase were prepared in microplate wells, and the absorbance at 405nm was recorded after incubation at $37^{\circ}C$ for 30 min. A linear relationship was obtained in the range of 0.1-1 U of lipase activity by this method. The reaction conditions were also optimized for the range of 0.01-0.1 U or 1-10 U. When assaying crude tissue extracts, the reaction of DTNB with non-specific reducing agents created a major source of error. However, this error was corrected by the use of blank samples that did not contain DMPTB.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.26-26
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• 2011

Colorimetric chemosensors are now considered as one of the most effective analytical method used in the environment monitoring. Colorimetric chemosensor for pH sensing can easily detect the primary danger or change of the surrounding environment pollution and source of infection and can prevent danger in the various fields. Quinaldine and Indole based colorants having the function of colorimetric chemosensors were synthesized and applied to textiles by the LBL method and electrospinning. The characteristics of colorant containing nanofibers and colored textiles were investigated if they can be used as environmental monitoring chemosensors.