Showing papers on "Color reaction published in 2016"

A simple and sensitive Ce(OH)CO3/H2O2/TMB reaction system for colorimetric determination of H2O2 and glucose

Abstract: The detection for H2O2 is essential in many areas, including life activity, medical diagnosis, industry and agriculture production and environmental monitoring, etc. This work developed a simple and sensitive two-step reaction system Ce(OH)CO3/H2O2/TMB for H2O2 determination. Upon sequential addition of H2O2 and TMB to Ce(OH)CO3 powders, a typical color reaction occurred quickly, producing a characteristic blue color in a slightly acidic aqueous solution. The underlying reaction mechanism was proposed based on the color reaction catalyzed by mimetic enzyme. The dependence of the color depth on H2O2 concentration enabled the colorimetric determination of H2O2. This reaction system responds linearly and quickly in a wide H2O2 concentration range of 0–80 μM, and achieves a detection limit of 0.3 μM H2O2 and a relative standard deviation lower than 5.1%. This H2O2 sensing system was modified to allow for the detection of glucose since H2O2 is one of the main products in the oxidation reaction of glucose catalyzed by oxidase enzymes. In addition to a wide linear response, a low detection limit and a high reproducibility, our present reaction system for glucose determination showed a highly specific response to glucose due to the specificity of glucose oxidase to glucose.

Determination of phenols by the amino antipyrine method

Abstract: there was a need for a rapid method for the determination of phenol. A rapid method would provide the information required as a guide for subsequent treatments and would make possible the analysis of a large number of samples. From a review of the literature, it was believed that a method based on the reaction of 4-aminoantipyrine reagent with phenol might be readily applied to this problem. The purpose of the present paper is to present additional information on the use of 4-amino antipyrine as a reagent for the simple and rapid determination of phenols. In 1943 Emerson (3) reported that in alkaline solutions phenols react with 4-aminoantipyrine in the presence of oxidizing agents to form intensely col ored compounds. He also pointed out the structural requirements that must be met by the phenolic compounds if the color reaction is to take place and listed a large number of organic com pounds and their reactions with 4 aminoantipyrine. The aminoantipyrine reaction was used by Gottlieb and Marsh (6) as the basis for the determination of certain preservatives, germicides, and other similar phenolic compounds. These same authors also presented absorption curves of the color produced with the various compounds, in addition to a detailed procedure.

Extractive Spectrophotometric Determination of Platinum in Cisplatin Injection, Alloys and Catalysts Assisted by 2-nitrobenzaldehydethiocarbohydrazone

Abstract: A simple, rapid, selective and sensitive spectrophotometric method for the determination of platinum(IV) was developed, based on the color reaction between platinum(IV) and 2nitrobenzaldehydethiocarbohydrazone (2-NBATCH) in the pH range 6.4-7.8. The red colored species have been developed after heating the reaction mixture in boiling water bath for 5 min and it was extracted into chloroform. The complex has an absorption maximum at 440 nm. A 20 fold of excess of reagent was required for complete complex formation. Beer’s law was obeyed for platinum(IV) concentration in the range of 4-12 µg mL-1 and the optimum concentration range was 6-12 µg mL-1 of platinum(IV) as evaluated by Ringbom’s plot. The molar absorptivity and Sandell’s sensitivity were 1.03  104 L mol-1 cm-1 and 0.0189 µg cm-2, respectively. The effect of pH, heating and extraction time, concentration of reagent and interference from various ions were investigated. The stoichiometry of the extracted complex was determined by Job’s method of continuous variation, mole ratio method and slope ratio method. It was found that metal to ligand ratio was 1:2. The developed method has been successfully applied to the determination of platinum(IV) in pharmaceutical samples, catalyst and synthetic alloy sample.

Spectrophotometric Determination of Haloperidol in Pure Form and Pharmaceutical Formulation using Calcon and Amido Black

Abstract: Two simple, rapid and sensitive spectrophotometric methods have been developed for determination of Haloperidol (HP) in pure form and pharmaceutical formulations. A good sensitive colour reaction has been developed, based on the fact that Haloperidol (HP) reacts with a Calcon (Cal) or Amido Black (AB), to form an ion-association complex in acidic buffer solution, giving pink color with Calcon and blue color with Amido Black, the absorbance of chloroform extracted complexes were measured at 531 nm and 626 nm respectively. The effects of analytical parameters on the reported systems were investigated. The complexation reactions were extremely rapid at room temperature and the absorption values remain unchanged up to 72 h. Beer's law was obeyed in the concentration ranges of 1.20 – 33.83 μg.ml-1 and 0.752 -30.00 μg. ml-1, detection limits were 0.142 and 0.085 μg.ml-1 and the molar absorptivity coefficients were 2 1817 and 2 3230 l.mol-1.cm-1 for Cal and A.B respectively. Recoveries were between 99.35–101.67% for HP-Cal and between 98.67–100.87% for HP-AB complexes. The two methods were successfully applied for the determination of commercially available haloperidol in pure and in pharmaceutical formulations (tablets and dropes) without interference from its excipients. Statistical comparison of the results of the proposed method with those of the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

Reagent for detecting heavy metal ions in printing and dyeing wastewater

Abstract: The invention discloses a reagent for detecting heavy metal ions in printing and dyeing wastewater. The reagent is characterized by comprising components of raw materials in parts by weight as follows: 30-40 parts of a HEPES buffer solution, 6-9 parts of ethylene diamine tetraacetic acid, 6-8 parts of ammonia water, 2-4 parts of a color developing agent, 2-4 parts of sodium sulfite, 3-5 parts of nanoscale ceramic powder, 3-5 parts of ammonium citrate, 1-3 parts of dimethylglyoxime, 2-4 parts of a surfactant and 3-5 parts of a solvent. The components of the reagent have a synergistic effect, the reagent is applied to large-scale screening detection of copper sulfate in wastewater as well as heavy metal cadmium in water samples and the like and is very applicable to basic level detection, the color developing agent is more sensitive in reaction when detecting whether the content of heavy metals exceed a standard or not, when the content of the heavy metals is lower than the limit specified by the national standard, color reaction still exists, the detection efficiency is higher, the content of the heavy metals in water can be preliminarily detected whenever and wherever possible, the detection sensitivity is high, operation is simple, the detection speed is high, and usage is convenient.

Process for preparing high-purity gardenia red

Abstract: The invention discloses a process for preparing high-purity gardenia red. According to the process, gardenoside serves as the raw material; methyl ester bond hydrolysis is conducted under the action of alkaline or lipase/esterase; pH is adjusted by adding citric acid or inorganic acid, and carboxyl is formed under the acidic condition; beta-glucosidase hydrolysis is conducted under the appropriate condition; primary amine compounds are added under the deoxygenated condition, and a color reaction is conducted; then refining and drying are conducted, so that the high-purity gardenia red is obtained. The process comprises the following steps of conducting a hydrolysis reaction on methyl ester bonds, adjusting pH till the acidic environment is obtained, conducting a hydrolysis reaction on beta-glucosidase, conducting a color generation reaction, conducting separating purification, conducting drying and formation and conducting detection and verification. By means of the process, reaction time for preparing gardenia red can be remarkably shortened; the obtained gardenia red is high in hue, high in yield and good in stability; the technological process is simple and easy to implement and convenient to apply and popularize.