Showing papers on "Color reaction published in 2008"

Micelle-mediated extraction and spectrophotometric determination of ammonia in water samples utilizing indophenol dye formation

Abstract: A rapid, selective and sensitive cloud point extraction process using the mixture of nonionic surfactant, Triton X-114, and cationic surfactant, cetyltrimethylammonium bromide (CTAB), to extract indophenol formed in the Berthelot reaction with ammonia from aqueous solutions was investigated. The method was based on the color reaction of ammonia with phenol under suitable oxidizing conditions in alkaline medium and cloud point extraction of produced indophenol dye. Effects of reaction and extraction parameters were studied and optimum parameters were established. Linearity was obeyed in the range of 2.00-125.00 ng mL-1 of ammonia. The detection limit of the method was 1.00 ng mL-1 of ammonia. The interference effect of some common ions was also tested. The method was applied to the determination of ammonium in natural water samples.

A new spectrophotometric method for direct determination of iron (III) in serum

Abstract: Bakground and purpose of the study: Hydroxypyridin-4-ones, a group of iron chelators have shown promise as potential compounds for the treatment of iron overload by the oral route. Their selectivity and high complex formation constant with iron makes them good candidates for iron determination. In this study the use of N-ethyl-2-methyl-3-hydroxypyridin-4-on (EMHP), a strong and selective ferric chelator, as a new ligand for measurement of µmolar concentrations of iron in aqueous solutions and biological fluids was investigated. This measurement is based on the color reaction of Fe 3+ with EMHP. Methods: After mixing serum sample and reagent, and incubating at room temperature, the absorbance of the resulting complex was measured at λmax. The effect of analytical variables, such as the amount and the kind of the reagents, pH, ratio of EMHP/Fe (III) and presence of other ions in determination of iron were studied. Results: The results showed that the optimum wavelength for the measurement was 456 nm. Formation of the complex was completed in less than 20 min and it was stable up to 24 hrs. Molar ratio of 6-10 EMHP/Fe (III) and pH = 5 were the optimum conditions for complex formation and determination of Fe (III). The detection limit was 2.5×10 -6 M of Fe (III) in serum or plasma. Ions commonly associated with iron did not interfere in the present method.

Novel Reaction for Rapid, Simple, and Sensitive Determination of Molybdenum in Various Samples

Abstract: A new sensitive, selective, rapid, and reproducible method is presented for the analysis of trace amounts of molybdenum (VI) (Mo(VI)). The method is based on the reaction of molybdenum (VI) with a new analytical reagent, 6‐(5‐Chloro‐2‐hydroxy‐4‐sulfophenylazo)‐5‐hydroxy‐1‐naphthalenesulfonic acid, disodium salt. Under optimum reaction conditions, molybdenum (VI) forms a red complex with a maximum absorption peak at 589 nm. The color reaction is rapidly completed at room temperature. The apparent molar absorption coefficient and Sandell sensitivity were 1.13×104 L · mol−1 · cm−1 and 0.0084 µg · cm−2, respectively. Beer's law was obeyed up to 8.5 µg · mL−1. Methods for the determination of Mo(VI) by first‐derivative spectrophtometry have also been proposed at 547 and 625 nm. The proposed methods offer the advantages of sensitivity, rapidity, selectivity, and simplicity without any prior separation or extraction. The methods have been applied to the determination of Mo(VI) in various environmental s...

Novel nessler's reagent and method for rapidly measuring soil ammonium nitrogen

Abstract: The invention discloses a novel Nyquist reagent and a method using the reagent for rapidly determining soil ammonium The main improvement of the novel Nyquist reagent lies in that proper amount of solid potassium hydroxide or sodium hydroxide is directly added in solution after the complete reaction of potassium iodide and mercuric chloride during the preparation; the novel Nyquist reagent is used for determining the soil ammonium; tartaric acid potassium sodium alkaline solution is used as masking agent, the novel Nyquist reagent is added in Arabic gum medium solution for the color reaction with ammonium ions Alkaline is added for adjusting the alkalinity of a color reaction system for the colorimetric determination after the color is stable The Nyquist reagent has the advantages of wide linear range, long shelf life, color stability and easy preparation The determination method of the invention has the advantages of easy operation, good reproducibility, small error and rapid test speed and is applied to bases and agricultural extension departments

Reagent kit for detecting formaldehyde in flash milk

Abstract: The present invention relates to a reagent case, in particular to a reagent case for detecting formaldehyde in raw milk, and belongs to the technical field of chemical components detecting equipment. The formaldehyde quickly detecting reagent case of the present invention is a case which is composed of a device of movable liquid, reacting liquid and a standard color comparing card, wherein the reacting liquid is prepared with the weight proportion of sodium hydroxide, phloroglucinol and water is (10-14) to (0.5-1.5) to 100. The standard color comparing card is a color card with rosiness series, and the lowest detecting limit of the card is 3.8microgramme per ml. Only one step operation of adding reagent is needed in the method, and the color reaction is fast. Only one minute is needed. The measuring condition is relatively loose. The sensitivity is high and the cost is low.

Novel Spectrophotometric Method for Determination of Trace Germanium in Soils with Methybenzeneazosalicylfluorone using Ultrasound-Assisted Leaching

Abstract: The research describes a very novel method for spectrophotometric determination of trace germanium in soils. The method is based on the color reaction of germanium (IV) with a new reagent, methybenzeneazosalicylfluorone (MBASF), in the presence of 6.0 M phosphoric acid and Triton X‐100. The reaction can complete rapidly and form a 1∶2 red complex with a maximum absorption at 501 nm under room temperature. The absorbance of the complex at 501 nm increases linearly with the concentration up to 18 µg of germanium (IV) in 25 mL of the solution; the apparent molar absorptivity was 2.18 ×10 5 L mol−1 cm−1. The interference study shows the reaction system has an excellent selectivity. All common metal and interference ions reported in other literatures can be tolerated in considerable amounts. The analytical characteristics in sensitivity and selectivity are superior over all reagents reported previously. Moreover, a very simple procedure was also developed for the dissolution of soil samples in the wor...

Composite reagent kit for checking textile formaldehyde content

Abstract: The invention discloses a composite reagent case that is used for detecting formaldehyde content of fabrics, which comprises a composite reagent A, a composite reagent B, a nano titanium dioxide reagent and a standard matching sample; wherein, the composite reagent A is prepared by evenly mixing a commercial 0.1 percent butyl phthalate and a commercial 2 percent sodium sulfite according to the weight ratio between 1 to 1 and 1 to 4; the composite reagent B is prepared by evenly mixing a 0.5 to 2 percent phenethyl alcohol solution and a 0.1 to 0.5 percent sulfuric acid solution according to the weight ratio of 1 to 1; the standard matching sample is a color reaction solution group with standard formaldehyde content or a color comparison card. The composite reagent case has convenient use and fast detection, can obtain final reaction solutions with different colors according to the formaldehyde with different densities, can easily distinguish the formaldehyde content in test samples, and has simple and fast operations as well as accurate and reliable results.

Spectrophotometric Determination of Iron with 2-(5-Carboxy-1,3,4-Triazolylazo)-5-Diethylamino Aniline

Abstract: Optimum conditions of color reaction of a new reagent 2-(5-carboxy-1,3,4-triazol-ylazo)-5-diethylamine(CTZAN) with iron(Ⅲ) was studied.The results showed that the CTZAN reacts with iron(Ⅲ) to form a 2:1 stable purple red complex in the buffer solution of HAc-NaAc with pH 6.0.The maximum absorption wavelength is at 570 nm.The apparent molar absorptivity is 2.08×104 L·mol-1·cm-1.Beer's law is obeyed in the range of 0.08-0.8 μg/mL for iron(Ⅲ).The method has been used for the direct determination of iron in aluminium alloys and pure aluminium.The results compare favourably with the certified values.

Radiation-Induced Reaction of Sulfonamide-Containing Polymers in the Film State for Color Imaging

Abstract: A polysulfonamide and copolymers consisting of sulfonamides and amides underwent Fries rearrangement and scission, forming amino groups upon EB irradiation. The EB irradiation of these films with a dose of 500 μC. cm -2 , followed by the color forming reaction provided the color imaging of line/space patterns with a resolution of 300 nm.

Rapid detecting method for detecting formaldehyde doped in flash milk

Abstract: The present invention relates to a detecting method, in particular to a quick detecting method which can detect mixed formaldehyde in raw milk, and belongs to the technical field of chemical components detection In the quick detecting method which can detect mixed formaldehyde in raw milk provided by the present invention, the proportion of reagent A, reagent V and weight of water is (10-14) to (05-15) to 100 The proportion of the weight of the raw milk and a mixed reagent is (4-8) to 1 After a period of time, whether formaldehyde exists can be qualitatively judged according to the color reaction Only one kind of mixed reagent is needed to be prepared in the method and only one step operation of adding reagent is needed to be carried through The color reaction is fast and only one minute is necessary The measuring condition is relatively loose The sensitivity is high and the cost is low

Trace level extraction and spectrophotometric determination of cyanide in waste water and biological fluid

Abstract: An extractive spectrophotometric method for the determination of cyanide in wastewater is developed. Cyanide is reacted with bromine to form cyanogen bromide, which subsequently reacts with pyridine. Glutaconic aldehyde is formed through the heterolytic cleavage of pyridine ring, which is then coupled with 4-amino salicylic acid. A yellow orange dye formed in alkaline medium is extractable in ;;-butanol in acidic medium. The extract shows absorbance maxima at 520 nm. The system obeys Beer's law in the range of 0.03-0.20 μg/mL. Important analytical parameters such as time, temperature, reagent concentration, acidity etc. have been optimized for complete colour reaction. Sandell's sensitivity and molar absorptivity for the system have been calculated. The method has been successfully applied for determination of cyanide in wastewater and biological fluid.