Study on Determination of Content of Phenol in Kiwifruit by Folin Method
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Absorbance
Recovery rate
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Objective To determine the water-soluble total sugars in water extract from Malussieboldii.Methods The total sugars in water extract of Malussieboldii after acid hydrolysis and extracted with ethyl acetate were determined with the anthrone-sulfuric colorimetry in which the glucose was used as standard reference.Results The concentration of glucose showed a good linearity with absorbance in the range of 7～35 μg/mL at 620 nm(r=0.998 1,n=6).The average water soluble total sugars of three shipments of Malussieboldii was 13.1%,the average recovery was 94.1%,and RSD was 1.0 %(n=6).Conclusion The method can improve the absorption peak remarkably with differential spectrophotometry(△A method) to eliminate the colored matrix and organic interference,which can provide a reliable and repeatable method for determination of the water-soluble total sugars in Malussieboldii extractions.
Colorimetry
Absorbance
Spectrophotometry
Water soluble
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A simple, precise, sensitive and accurate method was developed for the dedermination of trace quantities of phenol. The method is based on the inhibitory effect of phenol on the reaction between bromate and methyl orange in acidic media at 80℃. Phenol could be determined in the concentration range of 0. 40-3. 0 μg/mL,the detection limit is 0.18μg/mL,The relative standard deviation for eleven replicate determination of 1. 0 μg/mL of phenol was 1. 44%. The proposed method was applied to determination the phenol in river water and sewage with satisfactory results.
Relative standard deviation
Methyl orange
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Tannic acid
Tannin
Absorbance
Sodium hydroxide
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Objective:To develop a simple and sensitive method for the determination of trace phenol in water samples of environment.Methods:Based on the catalytic effect of phenol for the oxidation of arizarin red(AR) by potassium bromate in sulphuric acid medium,a catalytic spectrophotometric method was proposed for the determination of trace phenol.Results:The linear range and the determination limit for phenol were 0.08～1.20 μg/ml and 0.046 μg/ml,respectively.The RSD was 1.92%,2.24%,The recovery rate was 97.5%~104.0%.Conclusion:It is quick and simple with little interference.It can be applied to the determination of trace phenol in water samples of environment with satisfactory results.
Potassium bromate
Linear range
TRACE (psycholinguistics)
Bromate
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This article represents an experimental research of a colourmetric method for the estimation of vitamin C by using phenol reagent The result shows that absorption maximum of wavelength of the blue compound gained by interaction of ascorbic acid with phenol reagent is 750 nm. There is a positive relation between the optical density and Vit C concentration in the range of concentration of 1.14-45.4 μmol/L The colour produced by vitamin C standard material and the phenol reagent was stable from 10 minutes to 5 hours, but the colour produced by samples of plasma interacting with the phenol reagent became stable 45 minutes later. The recovery rate of the method is 98.2%-102.8%, and the coefficient of variation of precision test is 4.33%. The value of 16 samples of normal human plasma obtained by the method was very closed to the value obtained by classical 2,4-dinitrophenylhydrazin method at the same time (r=0.98, P0.01) and is in accord with what is reported in the literature.
Coefficient of variation
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Tannic acid
Molar absorptivity
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Cresol
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A new spectrophotometric method for determination of trace potassium bromate in wheat flour was proposed with oxidation-decolration of phenol red.The effects of some important factors,such as acidity,the concentration and the volume of phenol red,the reaction time and temperature on the determination were investigated.The results showed that the optimum conditions were as followes:the maximum absorption peak of 504nm,0.5mol/L hydrochloric acid,phenol red concentration of 1.00×10-4mol/L for 1.00mL,the temperature of 85℃ and the reaction time of 10min.Beer's law was obeyed in the range of 0—0.45μg/mL for potassium bromate.The regression equation was ΔA=0.6094C-0.0013(C:μg/mL)with the correlation coefficient of 0.9991.The detection limit for the amount sample of 5g was 0.01μg/g with the molar absorptivity coefficient of 3.6×106L·mol-1·cm-1.The method was used in the determination of trace potassium bromate in wheat flour with satisfactory results.The recovery of sample was in the range of 93%—103%,and the relative standard deviation was below 5%.
Potassium bromate
Molar absorptivity
Hydrochloric acid
Bromate
Spectrophotometry
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(1) 15°貯蔵過程に於ける牛肉抽出液中のWalkiewicz反応, pH, Cu-Folin呈色度並びに蛋白波相互の間の関係を比較検討した. (2) 中肉,肩ロース,ロース,肩三角,バラ肉,ヒレ先の六部位から得られた牛肉抽出液中のWalkiewicz反応, pH, Cu-Folin呈色度並びに蛋白波は,試料の相違により,貯蔵の進むにつれて夫々異った変化を示した. (3) 六部位のいずれの場合にも,同一試料内に於けるWalkiewicz反応, pH, Cu-Folin呈色度並びに蛋白波相互の間には,貯蔵の進むにつれて,常に密接な関係をとりつつ,一定の変化を示した. (4) 水抽出液蛋白波はpHや水抽出液Cu-Folin量色度と,また,食塩抽出液蛋白波は食塩抽出液Cu-Folin呈色度と,腐敗の進むにつれて夫々ほぼ相平行した変化を示し,前者の場合には増大,後者の場合には減少傾向をとった.
Polarography
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