Photometric determination of quaternary ammonium compounds with hexanitrodiphenylamine. II

In strongly alkaline medium (more than 0.1 N NaOH) hexanitrodiphenylamine anion reacts with base. The reaction is rather slow and is partly reversible.Quaternary ammonium ions can be determined by extraction of their hexanitrodiphenylamine complexes with chloroform or methylene chloride at pH 11 or with methylene chloride from 3N NaOH. Only the latter method is applicable to compounds containing several quaternary ammonium groups. The compounds extracted have high molar extinction and good stability. Quaternary ammonium ions can be determined in the presence of amines, and in some cases determination of quaternary ammonium ions in admixture is possible.     

Simultaneous spectrophotometric analysis of aliphatic amines utilizing thermochromism of charge-transfer complexes with tetrabromophenolphthalein ethyl ester.

Aliphatic amines, such as n-hexylamine (primary), di-n-hexylamine (secondary) and tri-n-hexylamine (tertiary amine), react with tetrabromophenolphthalein ethyl ester molecules (TBPEH) to form reddish or red-violet charge-transfer complexes (CT complexes) in 1,2-dichloroethane (DCE). The absorption maxima of the CT complexes with all primary amines occur at around 560 nm, with secondary amines at 570 nm and, with tertiary amines at 580 nm. The CT complex formation constants with TBPEH in DCE increase in the order of the primary, secondary and tertiary amines, but their constants decrease quantitatively with an increase in temperature. This phenomenon (thermochromism) could be applied to the simultaneous spectrophotometric determination of primary amine and secondary amine, or secondary amine and tertiary amine in a mixed solution utilizing the difference of absorbance with temperature changes.     

Study on Colour Reaction of Tungstogermanic Acid and Basic Organic Dyes

At the present time, the derivative of fluorones,the ion-association complexes of heteropoly acid-basic dyes etc, have been applied to the spectrophotometric determination of trace amounts of germanium. By the use of above methods the ion-association complexes will result in a better stable and selective absorbance.     

The analysis of aliquat-336 by gas chromatography

The determination of the quaternary ammonium components of Aliquat-336 by gas chromatography using tetraheptylammonium chloride as an internal standard is described. The method relies on the fact that long-chain quaternary ammonium salts undergo thermal decomposition at high injection port temperatures to form tertiary amines. The major component in Aliquat-336 is methyldioctyldecylammonium chloride with up to four other quaternary ammonium compounds being present. Aliquat-336 also contains 1-octanol and 1-decanol and some water.     

Two-phase titration of organic ammonium ions with lauryl sulphate and methyl yellow as indicator

Conditions for determination of quaternary ammonium compounds and amines by two-phase titration have been calculated on the basis of extraction constants for the ion-pairs between the titrant (lauryl sulphate), the indicator (Methyl Yellow) and the sample. Methods for determination of extraction constants are presented. The precision and selectivity of the method are demonstrated by titrations of ammonium ions with different structures and degrees of substitution. The results are in agreement with the theoretical calculations.     

Extraction—spectrophotometric determination of benzethonium and benzalkonium salts with bomocresol green and quinine

A method is described for the determination of benzethonium and benzalkonium compounds (1–5 × 10^?6 M) based on the formation of ion-associates with bromocresol green (BCG) and quinine in 1,2-dichloroethane. Benzethonium and benzalkonium are extracted quantitatively after the formation of a new type of ion-associate with BCG and quinine in an aqueous solution at pH 8.2. The ion-associate shows an absorption maximum at 630 nm. Many other quaternary ammonium species and amines do not interfere. The method is applied to a range of pharmaceutical products.     

Fluorimetric determinations by ion-pair extraction : Part V. Studies on ion-pair extraction with the fluorescent anion 9,10-dimethoxyanthracene-2-sulphonate

The fluorescent anion 9,10-dimethoxyanthracene-2-sulphonate has been studied in ion-pair extractions. Its ability to extract amines and quaternary ammonium compounds was investigated by fluorimetric determination of extraction and dissociation constants with methylene chloride as organic phase for two amines (amitriptyline and protriptyline) and two quaternary ammonium ions (tetrabutyl-and tetrapropylammonium). The optical properties of the anion and its ion pairs were characterized by quantum yield of fluorescence and a fluorescence sensitivity index. The determination of two of the ion pairs was studied, both after extraction to an organic phase and after a subsequent back-extraction of the anion component to an aqueous phase. Recoveries and standard deviations are given.     

Spectrophotometric determination of some histamine H1-antagonists drugs in their pharmaceutical preparations

Two rapid, simple and sensitive extractive specrophotometric methods has been developed for the determination of three histamine H1-antagonists drugs, e.g., chlorphenoxamine hydrochloride (CPX), diphenhydramine hydrochloride (DPH) and clemastine (CMT) in bulk and in their pharmaceutical formulations. The first method depend upon the reaction of molybdenum(V) thiocyanate ions (Method A) with the cited drugs to form stable ion-pair complexes which extractable with methylene chloride, the orange red color complex was determined colorimetrically at lambda(max) 470nm. The second method is based on the formation of an ion-association complex with alizarin red S as chromogenic reagents in acidic medium (Method B), which is extracted into chloroform. The complexes have a maximum absorbance at 425 and 426nm for (DPH or CMT) and CPX, respectively. Regression analysis of Beer-Lambert plots showed a good correlation in the concentration ranges of 5.0-40 and 5-70microgmL(-1) for molybdenum(V) thiocyanate (Method A) and alizarin red S (Method B), respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, detection and quantification limits were calculated. Applications of the procedure to the analysis of various pharmaceutical preparations gave reproducible and accurate results. Further, the validity of the procedure was confirmed by applying the standard addition technique and the results obtained in good agreement well with those obtained by the official method.     

Application of redox reactions in spectrophotometry-II Detection and spectrophotometric determination of phenolic compounds with the iron(III)/1,10-phenanthroline complex

To test the utility of the iron(III)/1,10-phenanthroline reagent system for the determination of organic compounds, its reaction with phenolic compounds has been characterized. By a redox reaction the reagent forms the chelate [Fe(phen)(3)](2+), which is extractable as ion-association complexes. Determinations based on these complexes are very sensitive.     

Spectrophotometric determination of titanium as tetraphenylarsonium or tetraphenylphosphonium thiocyanato-titanate

The spectrophotometric determination of titanium(IV) with thiocyanate by extraction of the tetraphenylarsonium and tetraphenylphosphonium ion-association complexes is described. The extracted complexes in chloroform have a maximum absorbance at 420 nm, obey Beer's law in the range 0.1–1 μg Ti ml^?1, and are stable for at least 5 hr. The molar absorptivity of the method is 7.5 × 10⁴ liters mol^?1 cm^?1. The described method is sensitive, selective, and reproducible. The composition of the extracted complexes was studied in solution and in solid state. The complexes [(C₆H₅)₄X]₂ [Ti(NCS)₆] (X = As, P) were isolated from the chloroform solution.     

非离子表面活性剂在胶束增溶分光光度法中的作用(Ⅱ)

本文以乳化剂OP对结晶紫及结晶紫-磷钼杂多酸缔合物的作用为代表,研究了非离子表面活性剂与碱性染料显色体系的相互作用,提出了非离子表面活性剂起增溶作用的第二种模式--拟均相萃取模式,并用浊点析相分离法进行了验证。     

Determination of bismuth in pharmaceutical products by resonance light scattering using quaternary ammonium salts as molecular probe

Resonance light scattering (RLS) of bismuth-iodide-quaternary ammonium salts and their analytical application have been studied. Bismuth can react with a large excess of I^? to form [BiI₄]^? in the presence of Tween-20; [BiI₄]^? further reacts with quaternary ammonium salts such as tetramethyl ammonium bromide (TMAB), tetrapropyl ammonium bromide (TPAB) and tetrabutyl ammonium bromide (TBAB) to form an ion-association compound. Moreover, the characteristics of RLS spectra of the complexes, the optimum conditions and the influencing factors have been investigated. The method has been applied to determine Bi(III) in pharmaceutical products with satisfactory results which are in agreement with that of atomic absorbance spectrometry (AAS).     

Calmagite as a spectrophotometric reagent for aluminium

Calmagite is proposed as a sensitive spectrophotometric reagent for aluminium, (570mmu) = 42000. After aqueous phase reaction at pH 8.6, the metal-reagent complex is extracted into chloroform by formation of an ion-association complex with a quaternary ammonium salt. The method is free from interference by common anions, and cationic interferences may be eliminated by the use of cyanide and EDTA as masking agents.     

Stepwise determination of quaternary ammonium salts and aromatic amines in pharmaceuticals by ion association titration.

A stepwise titrimetric method has been developed for the simultaneous determination of pharmaceutical quaternary ammonium salts (R4N+) and aromatic amines (R3N). The method is based on the solvent extraction of R4N+ and R3NH+ with an ion association reagent. Sodium tetrakis(4-fluorophenyl)borate and sodium tetraphenylborate were used as titrants and potassium tetrabromophenolphthalein ethyl ester (TBPE) was used as an indicator. The ion associate which formed between R4N+ ion and TBPE made a blue color in 1,2-dichloroethane, while the ion associate formed between R3NH+ and TBPE showed a red-violet one. Sample solutions containing quaternary ammonium and/or amine compounds were titrated with sodium tetrakis(4-fluorophenyl)borate or sodium tetraphenylborate. When one drop of excess titrant was added, the color of the organic phase turned from blue or red-violet to yellow at the equivalence point. On the other hand, in the mixture of R4N+ and R3N, the color changed from blue to red-violet at the first equivalence point, and then its color turned to yellow at the second equivalence point. The quaternary ammonium compound and aromatic amine in pharmaceuticals could be simultaneously and successfully determined by the proposed titration method.     

Sorption and permeation behaviour of metal thiocyanate complexes on cellulose acetate polymers

Various metal thiocyanate complexes in aqueous solution were sorbed on solid cellulose acetate polymers. The sorption selectivity increased in the order Zn(2+) > Fe(3+) > Cu(2+) > Co(2+) > Ni(2+). The sorption behaviour followed a Langmuir-type adsorption isotherm, and the maximum adsorption capacity was 6.1 x 10(-5) mole of complex per g of polymer under optimum conditions. The zinc species sorbed appear to be NH(4)Zn(H(2)O)(SCN)(3) or (NH(4))(2)Zn(SCN)(4) according to analysis of the sorption equilibrium. The ion-association species formed by the complex zinc anion and the ammonium ion was supposed to be sorbed (or "extracted") onto the polymer matrix. As an application of sorption of metal complexes, a new hyperfiltration process was proposed for selective separation of metal ions. Thus, a mixture of metal thiocyanate complexes was hyperfiltered through cellulose acetate membranes. Permeation of certain metal complexes was preferred, and the selectivity was found to be similar to the sorption selectivity. These findings lead to a generalized idea that hyperfiltration separation of ionic species, particularly anionic metal complexes, can be attained by using polymer membranes which selectively adsorb or extract such ionic species as ion-association complexes onto the polymer matrix.     

Spectrophotometry Determination Of Boron With 4-(P-Sulfophenylazo)-1, 8-Dihydroxynaphthalene

Abstract

4-(p-Sulfophenylazo)-l, 8-dihydroxynaphthalene (SPADN) was synthesized to study as a new reagent for the spectro-photometric determination of boron, measuring its absorbance on addition of boron present as boric acid at pH 8.6. The procedure involved mixing aliquots of the sample, ammonium buffer, EDTA and SPADN solutions. Various exchange equilibrium constants in the ion-association extraction systems of SPADN with zephiramine were also determined.     

Investigation of the extraction equilibrium of ion-association complexes of molybdenum (VI) with some polyphenols and thiazolyl blue. extraction-spectrophotometric determination of molybdenum

The extraction process of ternary ion-association complexes of molybdenum (VI) with some polyphenols (4-nitrocatechol, 2,3-dihydroxy naphthalene) and thiazolyl blue has been investigated by using an extraction-spectrophotometric method. The optimum conditions for their quantitative preparation in aqueous medium and subsequent extraction into an organic solvent have been found. The extraction, distribution and association constants, and the recovery factors have been calculated. The composition of the complexes has been determined. A precise, sensitive and simple extraction-spectrophotometric method for determination of molybdenum in products from ferrous metallurgy has been developed.     

Fluorimetric method for the determination of long-chain amines in water

A method is presented for the determination of long-chain quaternary ammonium salts, tertiary amines and secondary amines in water or aqueous raffinates, based on their extraction and fluorimetric determination as amine salts with Eosine Yellowish in toluene-hexanol (4:1) as solvent. No interferences were obtained from metal ions, or chloride, nitrate or phosphate ions when a back-washing method was applied to the sample extract. The method allows the determination of long-chain tertiary amines down to 4 ppM.     

Prochlorperazine bismethanesulfonate: Sensitive and selective reagent for the spectrophotometric determination of microgram amounts of osmium

Prochlorperazine bismethanesulfonate (PCPMS) is proposed as a new sensitive and selective reagent for the spectrophotometric determination of microgram amounts of osmium. PCPMS forms a red-colored species with osmium(VIII) or osmium(VI) instantaneously at room temperature in 5 M phosphoric acid medium. The red species exhibits maximum absorbance at 529 nm. Beer's law is valid over the concentration range 0.05–3.6 ppm for osmium(VIII) and 0.15–6.4 ppm for osmium(VI). Sandell's sensitivity of the reaction is 2.89 nm cm^?2 for osmium(VIII) and 4.24 ng cm^?2 for osmium(VI). The effects of time, temperature, acidity, order of addition of reagents, reagent concentration, and diverse ions are investigated. The application of the proposed method in the determination of osmium content in synthetic ores has been explored.     

Determination of nitrogen in solution by gas-phase molecular absorption spectrometry

Measurement of the molecular absorbance at 201 nm of the ammonia gas displaced from strongly alkaline solutions containing ammonium ions provides a rapid, sensitive and selective method for the determination of nitrogen. A simple apparatus based on an atomic absorption spectrometer is described. The method can be applied to the determination of the nitrogen content of soil and plant samples.