Mixed Anhydride Reagent Research Articles

Analysis of clozapine in its tablets using two novel spectrophotometric reactions targeting its tertiary amino group.

Two simple spectrophotometric methodologies have been proposed and validated for the measurement of an atypical antipsychotic drug Clozapine (CLZ). Method A depends on interaction of CLZ with N-bromosuccinimide(NBS) resulting in formation of a yellowish orange colored product, measured at 320nm. The linearity range was 5.0-70.0μg/mL. Method B depends on condensation of the same drug with acetic acid mixed anhydride reagent producing a purple colored product, measured at 319nm. The linearity range was 8.0-24.0μg/mL. All parameters affecting the reaction condition (volume of both reagent, temperature, time and the different diluting solvents) were optimized. Both methods were successfully applied to assay CLZ in its pure form and tablets giving mean percentage recoveries of (98.87±1.8 and 100±1.7) for method A, and corresponding values of (98.6±0.96 and 99.5±1) for method B. Besides, the study of reactions stoichiometry was performed and the reaction mechanisms were proposed.

Chromatographic analysis of thermoplastic polyurethanes based on hydroxy-terminated polycaprolactones after alkali fusion

An analytical procedure is described for the rapid qualitative analysis of polyurethane elastomers, based on polycaprolactonediols (CAPA). These thermoplastic polyurethanes are a complex reaction product of an isocyanate-terminated linear CAPA-based polyester prepolymer, extended with a 1,4-butanediol chain extender. The polymer is cleaved into the corresponding diamine, polyether, 6-hydroxycaproic acid, and 1,4-butanediol fragments by alkali fusion at high temperature. The fragments formed were analysed by gas and size-exclusion chromatography, after separation and derivatization. The polyethers were further cleaved into the corresponding polyol acetates by using a mixed anhydride reagent, before the gas chromatographic analysis.

Chromatographic analysis of thermoplastic polyurethanes based on hydroxy-terminated polycaprolactones after alkali fusion

An analytical procedure is described for the rapid qualitative analysis of polyurethane elastomers, based on polycaprolactonediols (CAPA). These thermoplastic polyurethanes are a complex reaction product of an isocyanate-terminated linear CAPA-based polyester prepolymer, extended with a 1,4-butanediol chain extender. The polymer is cleaved into the corresponding diamine, polyether, 6-hydroxycaproic acid, and 1,4-butanediol fragments by alkali fusion at high temperature. The fragments formed were analysed by gas and size-exclusion chromatography, after separation and derivatization. The polyethers were further cleaved into the corresponding polyol acetates by using a mixed anhydride reagent, before the gas chromatographic analysis.

Gas chromatographic analysis of polyether-based polyurethanes after acid fusion

An analytical procedure is described for rapid qualitative and quantitative analysis of polyether-based polyurethanes. Polyurethane foams are conventionally the complex reaction product of an isocyanate terminated branched polyether prepolymer extended with water. The polymer is cleaved into the diamine corresponding to the polyether portion of the polymer, by using mixed anhydride reagent. These products are analysed using gas chromatography after separation using liquid-liquid extraction procedure. The procedure is discussed and compared with an earlier reported scheme where the polymer was first fragmented by alkali fusion and the liberated polyether subsequently degraded using mixed anhydride reagent.

Gas chromatographic analysis of polyester-based polyurethane elastomers after acid fusion

An analytical procedure is described for the rapid qualitative and quantitative analysis of polyester-based polyurethane elastomers. The elastomers are normally the complex reaction products of an isocyanate-terminated linear polyester prepolymer cross-linked with either a diamine or a diol chain extender. The polymer is cleaved into the corresponding diamine, dicarboxylic acid and glycol acetate fragments by acid fusion using mixed anhydride reagent. These products are analysed by using gas chromatography, after separation using a liquid-liquid extraction procedure. Dicarboxylic acids are converted to dimethyl ester derivatives before gas chromatographic analysis, while diisocyanates are examined as the diamines and diols as acetyl derivatives.

Chromatographic analysis of thermoplastic, medical-grade, polyether-based polyurethane elastomers

An analytical procedure is described for rapid qualitative analysis of medical-grade polyether-based polyurethane elastomers. The elastomers are conventionally the complex reaction product of an isocyanate-terminated linear polyether prepolymer with either a diamine or a diol chain extender. The polymer is cleaved into the corresponding diamine, polyether, diol, or hydrocarbon by molten alkali fusion at high temperature. These fragments are analysed by gas and gel-permeation chromatography, after separation by a liquid—liquid extraction procedure. Polyethers are further cleaved into the corresponding polyol acetates by using a mixed anhydride reagent, before gas chromatographic analysis.

Spectrofluorimetric Determination of Opium Alkaloids by Mixed Anhydride Reagent

Abstract The spectrofluorimetric determination of five major opium alkaloids by malonic acid-acetic anhydride reagent is reported. The fluorescence characteristics of various alkaloidal systems and the effect of different parameters like temperature, time of heating and diluent on the fluorescence intensity are described. The interference of various foreign substances has also been checked.

Application of mixed anhydride reagent for the detection of some opium alkaloids on thin layer plates

Citric acid in acetic anhydride has been developed as a new chromogenic and fluorogenic reagent for the detection of 5 major opium alkaloids on thin layer plates. The colours and the fluorescence characteristics are reported. The sensitivity of the reagent by fluorescence has been found to be 0.5μg. The advantages of this reagent over some of the existing reagents are discussed.

Gas chromatographic analysis of ester‐type surfactants by using mixed anhydride reagent

AbstractPolyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether phosphates, and polyoxyethylene fatty acid ester‐type surfactants have been analyzed by gas chromatography after chemical decomposition by using the mixed anhydride of acetic and p‐toluene‐sulfonic acids. In this way, the hydrophobic groups of the polyoxyethylene alkyl ether sulfates and polyoxyethylene alkyl ether phosphates can be identified in the form of alkyl acetates, and the alkyl compositions can be determined easily. On the other hand, the hydrophobic groups of the polyoxyethylene fatty acid ester‐type surfactants, such as polyoxyethylene fatty acid ester, polyoxyethylene glycerol fatty acid ester, and polyoxyethylene sorbitan fatty acid ester, have been identified after conversion into their corresponding fatty acids. At the same time, the base compounds of the hydrophilic groups have been converted into ethylene glycol diacetate, glycerol triacetate, and isosorbide diacetate, respectively, so these surfactants may be distinguished easily.

Gas-chromatographic analysis of polyurethane polyethers by using a mixed anhydride reagent for the cleavage of ether linkages

The polyethers formed from propylene glycol, glycerol, trimethylol-propane [1,1,1-tris(hydroxymethyl)propane], pentaerythritol, sorbitol, triethanolamine, 1,2-diaminoethane and 2,2′-diaminodiethylamine, and which are used in the manufacture of polyurethane foams, have been qualitatively analysed by gas chromatography after conversion of the base compounds into their corresponding acetates by using the mixed anhydride of acetic and toluene-p-sulphonic acids as a reagent for cleavage for the ether linkages. The polyethers are allowed to react with the reagent at 120 °C for 2 hours. The reaction products are extracted with diethyl ether and the concentrated extract is subjected to gas chromatography. As, under appropriate conditions, the peaks of these acetates appear at different positions, they were easily distinguished.The proportions of oxyethylene and oxypropylene groups in the polyethers can also be determined by gas-chromatographic analysis of the acetylation products.