Showing papers on "Color reaction published in 1988"
TL;DR: A sensitive and selective colour reaction for the determination of nitrite is presented and the results obtained compare favourably with those from standard methods.
Abstract: A sensitive and selective colour reaction for the determination of nitrite is presented. Nitrite reacts with p-aminophenylmercaptoacetic acid in the presence of hydrochloric acid to form a diazonium cation, which is subsequently coupled with N-(1-naphthyl)ethylenediamine dihydrochloride in acidic medium to form a stable bluish violet azo dye. The method is suitable for the determination of nitrite from 0.02 to 0.80 p.p.m. in a 1.0-cm cuvette. The observed molar absorptivity and Sandell's sensitivity of the azo dye are 4.65 × 104 l mol–1 cm–1 and 0.001 µg cm–2, respectively. The method is free from most interferences. The method has been applied to polluted water samples and the results obtained compare favourably with those from standard methods.
68 citations
TL;DR: In this article, a structural analysis of substituted 3-arylazo-2-hydroxy-6-pyridones was based on the detection of the 2-hydrox-6 pyridone coupling component by reaction of the dye with zinc and resorcinol in dilute ammonia.
27 citations
TL;DR: The heterocyclic nucleus in tryptophan is oxidised byNitrous acid at elevated temperature to produce a phenolic intermediate which further reacts with nitrous acid to form a nitro compound that has a golden yellow colour in alkaline medium.
25 citations
Patent•
13 Dec 1988TL;DR: In this paper, a method and reagent for the determination of peracids is described, in which the sample solution is mixed with a chromogen, an iodide and, where appropriate, a buffer-containing reagent, and the color reaction is evaluated, either visually or by spectrophotometry.
Abstract: The invention relates to a method and reagent for the determination of peracids. The method is characterized in that the sample solution is mixed with a chromogen, an iodide and, where appropriate, a buffer-containing reagent, and the color reaction is evaluated, e.g., visually or by spectrophotometry.
22 citations
17 citations
TL;DR: Three new pyridoxine-glycosides were isolated from rice bran as colorless powder by various chromatographic techniques and were concluded to be 4'-O-(beta-D-glucosyl)-5'-O(beta-cellobiosyl)pyrid Oxine, and compound C to be 5'-O-beta- glucotriosyl-5'-o-(beta
Abstract: Three new pyridoxine-glycosides were isolated from rice bran (10kg) as colorless powder by various chromatographic techniques: compound A, 53mg; compound B, 7.8mg; compound C, 5.8mg. Compound A was shown to consist of pyridoxine and glucose in a 1:2 molar ratio by β-glucosidase hydrolysis, and by 1H-NMR and secondaryion mass spectrometry (SI-MS) data. On partial acid hydrolysis of the compound, cellobiose was liberated. Compound A showed the positive Gibbs color reaction, but the reaction was negative in the presence of boric acid. Thus, compound A was identified as 5'-O-(β-cellobiosyl)pyridoxine. The 13C-NMR spectral data were compatible with this structure. Compounds B and C were proven to be triglucosides of pyridoxine by enzymic hydrolysis and SI-MS data. From the results of the Gibbs color reaction and partial hydrolyses which yielded compound A, compound B was concluded to be 4'-O-(β-D-glucosyl)-5'-0-(β-cellobiosyl) pyridoxine, and compound C to be 5'-O-(β-glucotriosyl) pyridoxine in which a glucose molecule was bound to the cellobiosyl moiety of compound A through β-glycosidic linkage.
13 citations
TL;DR: A sensitive method for quantitative spectrophotometric determination of pyridine is described in this article, where the color reaction is based on the reaction of Pyridine with cyanogen-bromide to form glutaconic aldehyde, which is subsequently coupled with anthranilic acid.
9 citations
TL;DR: In this article, the color reaction between Xylenol orange (XO), zirconium (IV) and fluoride ions in the presence of various surfactants alone or in combination was studied at various pH.
Abstract: The color reaction between Xylenol orange (XO), zirconium (IV) and fluoride ions in the presence of various surfactants alone or in combination was studied at various pH. The XO -zirconium)IV)-fluoride ion ternary complex in mixed micellar media containing a low concentration of N-hexadecylpyridinium chloride (HPC) as a cationic surfactant and large amounts of (poly{oxyethylene)dodecyl ether (Brij 35) as a nonionic surfactant at weakly acidic media was found to be the most stable, and showed a remarkable bathochromic shift and clear contrast against a reagent blank. The maximum absorbance was at 600 nm in the mixed micellar media at pH 3.5, and the apparent molar absorptivities at 600 nm were 7.0 × 104 1 mol−1 cm−1 for zirconium(IV) and 1.4 × 104 1 mol−1 cm−1 for fluoride ion. The calibration curves covered the ranges of 0.5 ∼ 20.0 μg/10 ml zirconium! IV) and 0 ∼ 20.0 μg/10 ml fluoride ion with the Sandell sensitivities being 0.0013 μg/cm2 for zirconium(IV) and 0.0016 μg/cm2 for fluoride ion.
8 citations
TL;DR: In this article, the deep-blue compounds were discussed based on 13C NMR data, and it was concluded that the earlier structures should be partly re-revised, and the mechanism of formation of the deepblue compounds and the reaction of 1 with several hexahydro-1,3,5-triazines, which were prepared from formaldehyde and primary aliphatic amines, were also described.
Abstract: Rifamycin S (1) and 25-O-deacetylrifamycin S reacted with 1,3,5-tri-t-butylhexahydro-1,3,5-triazine to give deep-blue compounds. The structures of the deep-blue compounds are discussed based on 13C NMR data, and it is concluded that the earlier structures should be partly re-revised. The mechanism of formation of the deep-blue compounds and the reaction of 1 with several hexahydro-1,3,5-triazines, which were prepared from formaldehyde and primary aliphatic amines, are also described.
7 citations
TL;DR: In this paper, the molar absorptivity of U(VI) was found to be 4.65·103 1·mol−1·cm−1.5 and the optimum pH range for colour development was 1.5−3.5.
Abstract: Potassium ferrocyanide gives a colour reaction with U(VI), which is suitable for its determination. The complex absorbs in the wavelength range of 390–397 nm. The optimum pH range for colour development was 1.5–3.5. The molar absorptivity was found to be 4.65·103 1·mol−1·cm−1. Most of the anions up to 1000 μg did not interfere. The method was made selective by extracting U(VI) first with DOSO from the mixture of interfering cations from 1–2M HNO3 medium and then determining uranium in the back-extracted solution by developing the colour with ferrocyanide. 20 μg/10 ml of U(VI) in the final solution could be satisfactorily determined within an RSD of ±2%.
6 citations
TL;DR: The color reaction between various metal ions and o-hydroxyhydroquinonephthalein(Qnph) as a xanthene dye, in the presence of various water soluble surfactants alone or in combination, were systematically investigated at various pH areas as discussed by the authors.
Abstract: The color reaction systems between various metal ions and o-hydroxyhydroquinonephthalein(Qnph) as a xanthene dye, in the presence of various water soluble surfactants(cationic. anionic, non-ionic surfactants) alone or in combination, were systematically investigated at various pH areas. The coexistence of cationic and non-ionic surfactants, such as Zephiramine (Zp) and Brij 35, was most effective for the color reaction systems between Qnph and gallium(III), as a metal ion, at weakly acidic media. By using the color reaction between Qnph and gallium(III) in the coexistence of Zp and Brij 35, an improved and sensitive spectrophotometric determination of gallium(III) was proposed as method 1, and the calibration curve was rectilinear in the range of 0∼7.0 μg of gallium(III) in a final solution of 10ml at pH 6.4. The apparent molar absorptivity was 1.5 × 105 1 mol−1 cm−1 at 560 nm, and the interference of foreign ions was decreased by ½∼ ¼-fold in comparison with other methods; method 3—in the presen...
TL;DR: In this article, a glass wool plug between the reactants in the glass capillary was used to enhance the selectivity of the test by using a glass Wool plug between them.
Patent•
26 Sep 1988TL;DR: In this paper, the specific determination of the serum fructosamine content in blood or in samples obtained from blood by reaction with an appropriate color reagent and measurement of the color change is brought about, in which before the color reaction sample components with a non-specific reducing action and/or causing turbidity are removed and subsequently the color Reagent is added at a pH value of from 10 to 12.
Abstract: Process for the specific determination of the serum fructosamine content in blood or in samples obtained from blood by reaction with an appropriate color reagent and measurement of the color change thereby brought about, in which before the color reaction sample components with a non-specific reducing action and/or causing turbidity are removed and subsequently the color reagent is added at a pH value of from 10 to 12. The sample components are removed by treatment at approximately neutral pH value with a reagent composition comprising at least one enzymatic oxidation agent, optionally together with peroxidase and/or catalase and/or lipase, as well as with at least one SH group-blocking substance. A kit for the specific determination of the serum fructosamine content in blood or samples obtained from blood, comprises said reagent composition, a rebuffering reagent with a buffer which has an alkaline pH value and a color reagent for the detection of fructosamine.
Patent•
08 Sep 1988
TL;DR: A compound having the sequence of 1-24 amino acids from the side of the amino terminal expressed by the formula and the following physico-chemical properties was defined in this paper, where a human-derived cultivated and established lymphatic cell is added to a culture medium and an antitumor substance inducer was added to carry out cultivation.
Abstract: NEW MATERIAL:A compound having the sequence of 1-24 amino acids from the side of the amino terminal expressed by the formula and the following physico-chemical properties. Molecular weight; 19,000+ or -2,000 (measured by a gel filtration method using TSK gel G3000SW) and 16,000+ or -2,000 [sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE)]. Isoelectric point; pH4.9+ or -0.3. Ultraviolet absorption; Maximum value at 277nm and minimum value at 250nm. Aqueous solution; Weak acidic. Color reaction; Capable of assuming color reaction of peptide bonds and amino acids to the biuret reaction, Folin-Lowry reaction method and ninhydrin reaction after hydrolysis. USE:An antitumor agent. PREPARATION:For example, a human-derived cultivated and established lymphatic cell is added to a culture medium and an antitumor substance inducer is added to carry out cultivation. The resultant supernatant liquid is collected by centrifugation, subjected to ion exchange chromatography, ultrafiltered and concentrated and then subjected to gel filtration to afford the aimed low- molecular weight protein having antitumor activity.
Patent•
01 Aug 1988
TL;DR: The substance NF-86I has the following physicochemical properties: Appearance, brownish-yellowish powder; melting point, not showing clear melting point or decomposition point; element analysis (%), C, 56.30; H, 4.61; N, 1,000-10,000; solubility, soluble in water and ethanol and insoluble in hexane, ether, ethyl acetate and chloroform; color reaction, positive for ferric chloride reaction and negative for ninhyddrin reaction, p-anisidine-phthalic acid
Abstract: NEW MATERIAL:Substances NF-86I and II. The substance NF-86I has the following physicochemical properties: Appearance, brownish-yellowish powder; melting point, not showing clear melting point or decomposition point; element analysis (%), C, 56.30; H, 4.61; N, <=0.2; ash, <=0.3; mol.wt. (by dialysis tube), 1,000-10,000; solubility, soluble in water and ethanol and insoluble in hexane, ether, ethyl acetate and chloroform; color reaction, positive for ferric chloride reaction and negative for ninhyddrin reaction, p-anisidine-phthalic acid reaction, aniline diphenylamine reaction and Dragendorff reaction; stability, stable in powder state; etc. USE:alpha-Amylase-inhibiting agent useful in treatment of obesity and diabetes, prevention of tooth decay, diet auxiliary agent, etc. PREPARATION:For example, the novel substance is extracted from Areca [seed of Areca catechu L. (the family Palme)].
Patent•
29 Feb 1988
TL;DR: The antibiotic substance 55-C of formula has the following physicochemical properties Appearance, white powder; melting point, 178-180 degC; [alpha] D=$435 deg (CH3OH); molecular formula, C20H24O5; molecular weight, 344; solubility, easily soluble in chloroform, ethyl acetate, acetone and methanol, hardly soluble in benzene and insoluble in water and n-hexane; color reaction, positive to iodine vapor, KMnO4 reagent and 2,4-dinitrophen
Abstract: NEW MATERIAL:The antibiotic substance 55-C of formula It has the following physicochemical properties Appearance, white powder; melting point, 178-180 degC; [alpha] D=$435 deg (CH3OH); molecular formula, C20H24O5; molecular weight, 344; solubility, easily soluble in chloroform, ethyl acetate, acetone and methanol, hardly soluble in benzene and insoluble in water and n-hexane; color reaction, positive to iodine vapor, KMnO4 reagent and 2,4-dinitrophenylhydrazine reagent and negative to FeCl3, ninhydrin and indophenol reagent; etc USE:An antibacterial agent against Gram-positive bacteria and Gram-negative bacteria and an antitumor agent PREPARATION:Myrothecium verrucaria 55 strain (FERM P-8880) is cultured preferably under slightly acidic to neutral pH condition at about 30 degC
Patent•
19 Jul 1988
TL;DR: A strain such as Pseudomonas fluorescens biovar V (NJ-50A) (FERM P-9102), etc., is cultivated preferably at pH5-8 at 25-35 deg.C for 2-6 days as mentioned in this paper.
Abstract: NEW MATERIAL:Antibiotic RKO721 having the following properties. Molecular weight: 1216 (by mass spectrum). Melting point: not showing clear melting point, slightly browning at about 209-220 deg.C. specific rotatory power: [alpha]D =+3.0 (C=0.1, 50% pyridine water). Slightly acidic. White asbesto-like powder (lyophilized from 50% pyridine water). Color reaction: positive in ninhydrin and alpha-naphthol reaction and negative in Sakaguchi reaction. Soluble in pyridine, dimethyl sulfoxide, 1N-NaOH aqueous solution, 50% isopropanol aqueous solution and 50% pyridine aqueous solution, slightly soluble in 1N-acetic acid aqueous solution and methanol and insoluble water, isopropanol, chloroform and acetone. USE:An antifungal agent. PREPARATION:A strain such as Pseudomonas fluorescens biovar V (NJ-50A) (FERM P-9102), etc., is cultivated preferably at pH5-8 at 25-35 deg.C for 2-6 days.
Patent•
06 May 1988
TL;DR: SPF-PCO-30 has the following physicochemical properties: pH, 5.5-5.8 as 0.1% aqueous solution; color of material; white-slightly yellow; color reaction; positive or negative or Lowry reaction, Biuret reaction, ninhydrin reaction, anthrone sulfuric acid reaction and cysteine sulfide sulfide reaction and negative to orcin reaction; molecular weight; >=10,000 (gel filtration method); soluble in water, slightly soluble or insoluble in methanol, ethanol,
Abstract: NEW MATERIAL:An antitumor ingredient SPF-PCO-30 having the following physicochemical properties. Elementary analysis(%); C, 37.1.-39.3; H, 5.4-6.4; N, 3.5-4.8; O, 50.5-45.7; Ash, 3.5-3,8; decomposition point; changed to brown at 185 deg.C, black at 255 deg.C and decomposed; [alpha] =30-80 deg. (C=1.00); pH, 5.5-5.8 as 0.1% aqueous solution; color of material; white-slightly yellow; color reaction; positive or Lowry reaction, Biuret reaction, ninhydrin reaction, anthrone sulfuric acid reaction and cysteine sulfuric acid reaction and negative to orcin reaction; molecular weight; >=10,000 (gel filtration method); soluble in water, slightly soluble or insoluble in methanol, ethanol, n-prophanol, acetone, etnyl ether, chloroform, ethyl acetate, etc. USE:An antitumor agent. PREPARATION:Bacteria strains of the genus Streptococcus such as Streptococcus pyogenes ATCC 21060, etc., are incubated preferably anaerobically at pH 6.1-7.2 and 35-37 deg.C for 2-20hr.
TL;DR: In this paper, a method for the spectrophotometric determination of periodate was described based on the above properties, and the method was applied to 2-HBGH and showed that periodate is not oxidized by H2O2, IO3, BrO3 −, S2O8 =, S 2O5 =, ClO4 −, Cl O3 − and Cl o3 − under these conditions.
Abstract: Periodate oxidizes 2-HBGH to a red colored compound in ammonia medium. The reagent is not oxidized by H2O2, IO3 −, BrO3 −, S2O8 =, S2O5 =, ClO4 −, ClO3 − under these conditions. Based on the above properties a method is described for the spectrophotometric determination of periodate.
01 Jan 1988
TL;DR: The color reaction of Fe(III) with Tiron (H2L) at different pH values was studied by spectrophotometry and conductometry as discussed by the authors, and the effective pH ranges over which the green, violet, and red colored complexes remain const.
Abstract: The color reaction of Fe(III) with Tiron (H2L) at different pH values was studied by spectrophotometry and conductometry. Fe(III) reacts with H2L to form 3 complexes: FeL+, FeL2-, and FeL33-, depending on the pH of the soln. The effective pH ranges over which the absorbances of the green, violet, and red colored complexes remain const. are 1.5-3.0, 5.8-6.8, and 8.7-11.5, resp. The max. absorption wavelength intervals are 660-680, 558-568, and 468-484 nm, resp. Beer's law was obeyed in the ranges 0-33, 0-7.25, and 0-8.9 ppm for the green, violet, and red complexes, resp. The molar absorptivities and stability consts. of the 3 complexes are given. [on SciFinder(R)]
Patent•
19 Mar 1988
TL;DR: In this paper, the colour developing substances for colour reaction systems, consisting of colour developer and optionally solvents as well as further fillers and additives, are described, as colour developers, aromatic hydrocarbon resins in acid or salt form modified with aromatic carboxylic acids.
Abstract: The invention relates to colour developing substances for colour reaction systems, consisting of colour developer and optionally solvents as well as further fillers and additives. These substances contain, as colour developers, aromatic hydrocarbon resins in acid or salt form modified with aromatic carboxylic acids.
Patent•
18 Jan 1988
TL;DR: In this paper, the antibiotic substance F-0769 (FERM P-1264) belonging to the Streptomyces genus is cultured and the produced antibiotic substance is separated from the cultured product.
Abstract: NEW MATERIAL:The antibiotic substance having the following physical and chemical properties. Appearance, white or pale yellow powder; melting point, 245-250 deg.C; specific rotation, [alpha] D=-37.5 deg. (c=1, methanol); solubility, soluble in methanol, ethanol, acetone, chloroform, ethyl acetate and benzene and insoluble in water and hexane; elemental analysis (%), C 57.53, H 7.36, O 21.17, N 12.97; amino acid analysis, positive to threonine, valine and leucine; color reaction, positive to iodine reaction and potassium permanganate reaction, negative to ninhydrin reaction and ferric chloride reaction. USE:Antibacterial agent. PREPARATION:Streptomyces violaceusniger F-0769 (FERM P-1264) belonging to Streptomyces genus is cultured and the produced antibiotic substance F-0769 is separated from the cultured product.
Patent•
12 May 1988
TL;DR: In this paper, an antibiotic substance TM-611 (FERM P-8972) is cultured under aerobic condition and it exhibits the following physical and chemical properties as Na salt: Appearance, white acicular crystal; m.p., 203-205 deg.
Abstract: NEW MATERIAL:Antibiotic substance TM-611 exhibiting the following physical and chemical properties as Na salt. Appearance, white acicular crystal; m.p., 203-205 deg.C; elemental analysis (%), C 62.97, H 8.69, Na 3.16; molecular weight, FABMS m/z 705 (M+H) ; molecular formula, C37H61O11Na; [alpha]D =+29.2 deg. (c=0.5, CHCl3); solubility, insoluble in water and soluble in methanol, ethanol, acetone, ethyl acetate, benzene, chloroform and n-hexane; color reaction, negative to ninhydrin and FeCl3 reaction and positive to vanillin-sulfuric acid and iodine reaction; nature, weakly acidic in isolated state; etc. USE:An antibiotic substance exhibiting proliferation-inhibiting action against Gram-positive bacteria. Useful as pharmaceuticals, agricultural chemicals and feed additives. PREPARATION:Streptoverticillium olivoreticuli TM-611 (FERM P-8972) is cultured under aerobic condition.