Iodimetric determinations in organic solvents: Determination of manganese oxidation states in methylene chloride solutions

1990 ◽  
Vol 68 (1) ◽  
pp. 79-81 ◽  
Author(s):  
Joaquin F. Perez-Benito ◽  
Enrique Brillas ◽  
Conchita Arias
Keyword(s):  
Acetic Acid ◽  
Quaternary Ammonium ◽  
Glacial Acetic Acid ◽  
Methylene Chloride ◽  
Oxidation States ◽  
Manganese Oxidation ◽  
Chloride Solutions ◽  
Tetrabutylammonium Iodide ◽  
Organic Solutions

An iodimetric technique has been developed to quantitatively analyze the oxidants present in organic solutions. Addition of excess tetrabutylammonium iodide and excess glacial acetic acid results in the formation of tetrabutylammonium triiodide, whose concentration can be measured spectrophotometrically at 295 or 365 nm. Application of this technique to the determination of the final oxidation state of manganese in permanganate reactions in methylene chloride solutions is described. The equilibrium constant for formation of tetrabutylammonium triiodide in methylene chloride has been measured: K = (3.48 ± 0.12) × 104 at 25.0 °C. Keywords: iodimetric determinations, manganese oxidation states, methylene chloride, quaternary ammonium permanganate, quaternary ammonium triiodide.

scholarly journals Thin layer chromatographic compatibility study in preformulation of new transdermal therapeutic systems

2020 ◽  
Vol 66 (1) ◽  
pp. 23-29
Author(s):  
Octavia-Laura Moldovan ◽  
Diana-Nicoleta Brihan ◽  
Nicoleta Todoran ◽  
Aura Rusu
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Mobile Phase ◽  
Glacial Acetic Acid ◽  
Methylene Chloride ◽  
Hydroxyethyl Cellulose ◽  
Compatibility Study ◽  
Chemical Interactions ◽  
Miconazole Nitrate ◽  
Active Substances

AbstractObjective: The compatibility of four binary active substances combinations adapalene – levofloxacin (ADP-LFX), adapalene – miconazole nitrate (ADP-MCZ), levofloxacin – meloxicam (LFX-MLX) and levofloxacin – miconazole nitrate (LFX-MCZ) was analysed to be comprised in new transdermal therapeutic systems. Also, the compatibility of selected active substances and four polymeric excipients (hydroxypropyl methyl-cellulose - HPMC 15000, hydroxypropyl methylcellulose - HPMC E5, ethyl cellulose - EC 10, and hydroxyethyl cellulose – HEC) was studied.Methods: Thin layer chromatographic method (TLC) and four selected mobile phases were used. On the plate (in situ) were obtained the binary combinations (active substances and active substance-polymer).Results: A good compatibility of ADP-LFX was found using ammonia : methanol : acetonitrile : methylene chloride 2:4:1:4 mobile phase. Using chloroform : acetone : glacial acetic acid 34:4:3 on the chromatogram of ADP-MCZ, only ADP spots appeared but without changes in the shape of the spots and Rf values. Any modifications of LFX and MLX spots (from LFX-MLX mixture) had been observed using toluene : glacial acetic acid : methanol 11:1:0.5 mobile phase, although LFX spots have remained on the baseline. Only LFX spots were visible from LFX-MLX and LFX-MCZ mixtures (ammonia : methanol : acetonitrile : methylene chloride 2:4:1:4 mobile phase). Distinctive spots were observed for ADP, LFX and MLX with variable results from no chemical interactions to limited chemical interactions when the compatibility with polymers was verified.Conclusions: ADP-LFX and LFX-MLX mixtures were found to be compatible. ADP with HPMC polymers and LFX with HPMC E5 and HEC had presented excellent compatibility; for the other binary combinations, different analytical methods will be necessary.

Reverse Phase Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Bait Formulations

1982 ◽  
Vol 65 (4) ◽  
pp. 927-929
Author(s):  
Brian R Bennett ◽  
Gregory S Grimes
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Target Concentration ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Chlorophacinone and diphacinone are extracted at the 0.005% level from grain or paraffinized baits with glacial acetic acid. The target concentration is 0.01 mg/mL. The filtered supernate is chromatographed on a Partisil PXS ODS10/25 liquid chromatography column with premixed and degassed glacial acetic acid-tetrahydrofuran-water (14 + 2 + 9) and detected at 288 nm. The concentration is calculated by using an external standard. The recovery from spiked samples averaged 96.6% for both analytes. The response is linear from 0.001 to 0.040 mg/mL. The coefficient of variation of within-day replicates ranged from 1.1 to 2.5%.

Determination of Carbaryl Residues in Honey Bees

1965 ◽  
Vol 48 (4) ◽  
pp. 771-774
Author(s):  
D P Johnson ◽  
H A Stansbury
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Quantitative Determination ◽  
Honey Bees ◽  
Methylene Chloride ◽  
Hydrolysis Product ◽  
Separate Analysis ◽  
Yellow Substance ◽  
Hydrolysis Of

Abstract A method has been developed for detecting residues of carbaryl (1-naphthyl methylcarbamate) as well as its hydrolysis product, 1-naphthol, in dead bees. The method is based on extraction of the bees with benzene, followed by a cleanup involving liquid partitioning and chromatography on Florisil. The quantitative determination involves hydrolysis of carbaryl to 1-naphthol and coupling of the latter with p-nitrobenzenediazonium fluoborate in acetic acid to form a yellow substance. For separate analysis, free 1-naphthol is separated from methylene chloride into a basic aqueous solution. The sensitivity of the method is about 0.1 ppm; recoveries averaged 85.6 ± 6.6% for 1- naphthol and 83.8 ± 2.7% for carbaryl.

Method for the accurate determination of specific rotation. Specific rotation of valine and leucine

1969 ◽  
Vol 47 (15) ◽  
pp. 2739-2746 ◽  
Author(s):  
J. C. MacDonald
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Optical Rotation ◽  
Accurate Determination ◽  
Computer Calculation ◽  
Specific Rotation ◽  
Best Fit

The optical rotation of various concentrations of L-valine and L-leucine, dissolved in glacial acetic acid, or 5 or 6 M HCl, was measured with a photoelectric polarimeter at the nominal wavelengths 589, 578, 546, 436, and 365 nm and temperatures of 20, 25, and 30 °C. The specific rotation for any one wavelength, solute, and solvent could be defined by the equation [α]λT = A(1 + D(T − 25)) + BC, where T is temperature in °C, C is concentration in grams of solute per 100 ml of solution, and A, B, and D are constants. The best fit values of the constants were determined by computer calculation and are listed. Constants are also given for calculating a specific rotation based on grams of solute per 100 g of solution.

Determination of acetaldehyde in glacial acetic acid by gas chromatography

1974 ◽  
Vol 46 (11) ◽  
pp. 1584-1584 ◽  
Author(s):  
Harold J. Rhodes ◽  
David W. Bode ◽  
Martin I. Blake
Keyword(s):  
Gas Chromatography ◽  
Acetic Acid ◽  
Glacial Acetic Acid

Bromination of Acridine

2018 ◽  
Vol 71 (4) ◽  
pp. 285
Author(s):  
Graham S. Chandler ◽  
Wolfgang H. F. Sasse
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Quantitative Determination ◽  
Glacial Acetic Acid ◽  
Tiny Amount ◽  
Concentrated Sulfuric Acid

The quantitative determination of the products of bromination of acridine in concentrated sulfuric acid and glacial acetic acid is described. In both cases, the only monobromo products were the 2- and 4-substituted compounds. With sulfuric acid, the 4-isomer predominates whereas in acetic acid, the 2-isomer is predominant. This work expands substantially on the tiny amount of previous work on halogenation of dibenzo-annelated pyridines.

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