Simple, selective, and identifiable analysis of aromatic monoamines with a surrogate on sulfuric acid impregnated filters by derivatization with an acid chloride reagent and HPLC with fluorescence detection

2018 ◽  
Vol 41 (23) ◽  
pp. 4355-4362 ◽  
Author(s):  
Naoko Inoue
Keyword(s):  
Sulfuric Acid ◽  
Fluorescence Detection ◽  
Acid Chloride

Determination of Fluorene in Fish, Sediment, and Plants

1986 ◽  
Vol 69 (6) ◽  
pp. 944-951
Author(s):  
Jon A Lebo ◽  
Lawrence M Smith
Keyword(s):  
Liquid Chromatography ◽  
Activated Carbon ◽  
Sulfuric Acid ◽  
Silica Gel ◽  
Fluorescence Detection ◽  
Potassium Silicate ◽  
Limits Of Detection ◽  
Carbon Efficiency ◽  
Gel Permeation

Abstract Methods and their applications are described for the determination of fluorene in fish, sediment, and plants. Sample extracts are enriched by using 2 or more of the following: gel permeation, silica gel, potassium silicate, sulfuric acid-impregnated silica gel, and activated carbon. Efficiency was improved by applying the adsorbents in combination or as tandem enrichment modules. Analyses by liquid chromatography (LC) with ultraviolet or fluorescence detection (LC/UV or LC/F) yielded limits of detection of 30, 3, and 30 ng/g and average recoveries of 80, 81, and 74% for fish, sediment, and plants, respectively.

Microwave Assisted Solvent Free One Pot Synthesis of N-acetyl-bis-indoles

2019 ◽  
Vol 16 (7) ◽  
pp. 531-534
Author(s):  
K. Ravi Ganesh ◽  
V. Narayana Murthy ◽  
K. Raghavendra Rao ◽  
M.V. Basaveswara Rao ◽  
C. Murthy ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Microwave Irradiation ◽  
Acid Chloride ◽  
Solvent Free ◽  
Acid Chlorides ◽  
Silica Sulfuric Acid ◽  
One Pot ◽  
Microwave Assisted ◽  
One Pot Synthesis ◽  
Indole Compounds

The synthesis of various N-acetyl-bis-indole compounds has been achieved by one pot reaction of indole and acid chloride in the presence of silica sulfuric acid as a catalyst under microwave irradiation to moderate yields. The reaction has also been studied with different acid chlorides and solvents.

Synthesis of piperazine-2,5-diones related to bicyclomycin: 3-acetoxy-1,4-dibenzyl-3-[1-(2-methoxyethyl)- and 1-(2-hydroxyethyl)ethenyl]piperazine-2,5-dione. 1. Route via acyclic intermediates

1983 ◽  
Vol 61 (3) ◽  
pp. 519-528 ◽  
Author(s):  
Peter Yates ◽  
John Harold Hoare
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Oxygen Atom ◽  
Acetic Anhydride ◽  
Acid Chloride ◽  
Structural Features ◽  
Reaction Sequence ◽  
Hydroxyl Oxygen Atom ◽  
Compound 21 ◽  
Tetrahydropyranyl Ether

3-Acetoxy-1,4-dibenzyl-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione (32) and its 2-hydroxyethyl analogue (46), which possess several of the structural features of the antibiotic bicyclomycin, have been synthesized by a route involving construction of the piperazine-2,5-dione ring at a late stage in the reaction sequence. Treatment of ethyl 3-(2-methoxyethyl)-3-methylglycidate with acetic anhydride and sulfuric acid gives ethyl 2-acetoxy-3-(2-methoxyethyl)-3-butenoate (10), which is converted to the corresponding carboxylic acid by ethanolysis, hydrolysis, and reacetylation. This, on conversion to its acid chloride and reaction with N,N′-dibenzylglycinamide, gives 2-acetoxy-N-benzyl-N-(2-benzylamino-2-oxocthyl)-3-(2methoxyethyl)-3-butenamide (21). Compound 21, on hydrolysis and oxidation, gives the corresponding 2-oxo compound, which on treatment with magnesium isopropylcyclohexylamide followed by acetylation yields 32. Demethylation of 21 with alkylthiotrimethylsilanes gives the corresponding 2-hydroxyethyl compound, whose tetrahydropyranyl ether on subjection to the above reaction sequence gives the 2-(tetrahydropyran-2-yloxy)ethyl analogue of 32. This, on hydrolysis, gives a 3: 1 mixture of compound 46 and a spiro compound formed by displacement of the acetoxyl group by the hydroxyl oxygen atom of 46.

scholarly journals Determination of Methylbenzoquate in Premixes and Animal Feeds Using Liquid Chromatography with Fluorescence Detection

2005 ◽  
Vol 88 (3) ◽  
pp. 673-678
Author(s):  
Michal Douša ◽  
Karel Lemr ◽  
Zdeněk Stránský
Keyword(s):  
Liquid Chromatography ◽  
Sulfuric Acid ◽  
Fluorescence Detection ◽  
Solid Phase ◽  
Reversed Phase ◽  
Water Bath ◽  
Determination Limit ◽  
Limit Of Quantification ◽  
Limit Of Quantitation ◽  
Routine Identification

Abstract A rapid analytical procedure was developed and tested for routine identification and quantification of methylbenzoquate in feeds by liquid chromatography (LC). The ground feed samples were extracted using methanol–water (80 + 20, v/v) at 65°–70°C in a water bath for premixes and in dichloromethane at 45°C in a water bath for final feeds, respectively. The extract of final feeds was cleaned using solid-phase extraction on silica columns. Both the final feed and premix extracts were analyzed by reversed-phase LC on a NovaPak C18 column (3.9 × 150 mm; 4 μm) with methanol-acetonitrile-water-phosphoric acid (340 + 350 + 308 + 2, v/v) as mobile phase. Fluorescence detection was performed at excitation and emission wavelengths of 265 and 390 nm, respectively. Alternatively, post-column addition sulfuric acid solution was used to decrease the determination limit. The recovery of methylbenzoquate, in a concentration range of 0.5–10 mg/kg, was 105.0 ± 7.3%. The limit of quantitation, based on a signal-to-noise ratio of 10:1, was 48 μg/kg. The developed LC method was tested in an interlaboratory study. The interlaboratory repeatibility for both samples ranged from 7.1 to 10.6%; the interlaboratory reproducibility ranged from 11.7 to 15.2%. With the post-column addition of sulfuric acid, the limit of quantification was decreased by a factor of 50. Overall, the developed method is highly selective and can be used in routine analysis.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

1976 ◽  
Vol 34 ◽  
pp. 636-637
Author(s):  
R. E. Herfert ◽  
N. T. McDevitt
Keyword(s):  
Sulfuric Acid ◽  
Salt Spray ◽  
High Strength ◽  
Environmental Stability ◽  
Anodic Films ◽  
Sodium Dichromate ◽  
Corrosion Resistant ◽  
Aerospace Applications ◽  
Bond Strengths ◽  
Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

Sign in / Sign up

Export Citation Format

Share Document