A sensor for the in situ determination of acidity levels in concentrated sulfuric acid

1999 ◽  
Vol 365 (4) ◽  
pp. 310-313
Author(s):  
B. Hammouti ◽  
H. Oudda ◽  
A. El Maslout ◽  
A. Benayada
Keyword(s):  
Sulfuric Acid ◽  
Concentrated Sulfuric Acid

A Headspace Gas Chromatographic Method for Determination of Formic acid Content in Isosulfan Blue and in Various Drugs

2021 ◽  
Vol 37 (2) ◽  
pp. 321-329
Author(s):  
Nilesh Takale ◽  
Neelakandan Kaliyaperumal ◽  
Gopalakrishnan Mannathusamy ◽  
Rajarajan Govindasamy
Keyword(s):  
Sulfuric Acid ◽  
Formic Acid ◽  
Chromatographic Method ◽  
Isopropyl Alcohol ◽  
Class Iii ◽  
Drug Substances ◽  
Headspace Gas ◽  
Concentrated Sulfuric Acid ◽  
Gas Chromatographic Method

The Pharmaceutical industry uses formic acid in the manufacturing of various drug substances or API. At the time of manufacturing of API formic acid is use as an oxidizing agent. Formic acid is the simplest carboxylic acid. It also called methanoic acid.Formic acid present in API at high concentrations is very hazardous but in low concentrations is very beneficial. The developed and validated method was short, precise, cost effective and reproducible with FID detector and easy to use. The method is a selective and superficial analytical method for determination of formic acid in different drug substances. We report here the development and validation study of headspace gas chromatographic method to determine formic acid in different drug substances we are reported here. As per this method, the drug sample was dissolved in 0.1% (v/v) of concentrated sulfuric acid in isopropyl alcohol (IPA) in a GC headspace vial and 0.1% (v/v) of concentrated sulfuric acid in isopropyl alcohol used as a diluent. A AB-Inowax capillary column (30 m x 0.32 mm I.D. and 0.5 µm film thickness) was used under gradient conditions with FID. The formic acid peak was well separated from all other solvents that are used in synthesis of particular drug substance. The LOD and LOQof the method for formic acid are 82 ppm and 249 ppm respectively. Formic acid are low toxic class-III solvent as per ICH guideline.

Determination of Benzo (a) pyrene in Foods

1978 ◽  
Vol 61 (1) ◽  
pp. 129-135
Author(s):  
Yukio Saito ◽  
Hiroshi Sekita ◽  
Mitsuharu Takeda ◽  
Mitsuru Uchiyama
Keyword(s):  
Sulfuric Acid ◽  
Silica Gel ◽  
Column Chromatography ◽  
Analytical Method ◽  
Selective Extraction ◽  
Acid Extraction ◽  
Simple Method ◽  
Extraction Step ◽  
Concentrated Sulfuric Acid

Abstract An analytical method was developed for determining benzo (a) pyrene in foods, suitable for routine use. The method consists of 4 cleanup steps: (1) alkali cleavage of sample, (2) preliminary silica gel column chromatography, (3) selective extraction with concentrated sulfuric acid, and (4) further silica gel column chromatography. Recoveries of benzo- (a) pyrene added to 50 g (or 10 g) food at levels of 0.4 ppb (or 2 ppb) ranged from 70% for short-necked clam and mackerel to 85% for chicken meat. The sulfuric acid extraction step affords a simple method for isolating benzo (a)- pyrene from various kinds of interfering substances which could not be separated by existing methods.

Determination of Microgram Quantities of Inorganic Boron in Mammalian Specimens

1965 ◽  
Vol 11 (3) ◽  
pp. 378-385 ◽  
Author(s):  
T Konikowski ◽  
Lee E Farr
Keyword(s):  
Cerebrospinal Fluid ◽  
Sulfuric Acid ◽  
Boron Concentration ◽  
Clinical Chemistry ◽  
Mammalian Tissue ◽  
Mammalian Tissues ◽  
Concentrated Sulfuric Acid ◽  
Reference Graph

Abstract A method is presented for estimation of inorganic boron in mammalian tissues, blood, cerebrospinal fluid, and urine. The procedure is simple and rapid, qualifying it particularly to meet needs in clinical chemistry. The mammalian tissues are first enzymatically digested and extracted; then the deproteinized extract is allowed to react with quinalizarin in concentrated sulfuric acid. The intensity of the resultant color is read spectrophotometrically at 620 mµ. The boron concentration in the tissue analyzed is obtained from a standard reference graph for that tissue. The method is applicable to concentrations as low as I µg. of boron per gram of mammalian tissue or fluid.

scholarly journals A Headspace Gas Chromatographic Method for Determination of Formic Acid Content in Isosulfan Blue and Various Drug Substances

2021 ◽  
Vol 37 (02) ◽  
pp. 321-329
Author(s):  
Nilesh Takale ◽  
Neelakandan Kaliyaperumal ◽  
Gopalakrishnan Mannathusamy ◽  
Rajarajan Govindasamy
Keyword(s):  
Sulfuric Acid ◽  
Formic Acid ◽  
Chromatographic Method ◽  
Isopropyl Alcohol ◽  
Class Iii ◽  
Drug Substances ◽  
Headspace Gas ◽  
Concentrated Sulfuric Acid ◽  
Gas Chromatographic Method

The Pharmaceutical industry uses formic acid in the manufacturing of various drug substances or API. At the time of manufacturing of API formic acid is use as an oxidizing agent. Formic acid is the simplest carboxylic acid. It also called methanoic acid.Formic acid present in API at high concentrations is very hazardous but in low concentrations is very beneficial. The developed and validated method was short, precise, cost effective and reproducible with FID detector and easy to use. The method is a selective and superficial analytical method for determination of formic acid in different drug substances. We report here the development and validation study of headspace gas chromatographic method to determine formic acid in different drug substances we are reported here. As per this method, the drug sample was dissolved in 0.1% (v/v) of concentrated sulfuric acid in isopropyl alcohol (IPA) in a GC headspace vial and 0.1% (v/v) of concentrated sulfuric acid in isopropyl alcohol used as a diluent. A AB-Inowax capillary column (30 m x 0.32 mm I.D. and 0.5 µm film thickness) was used under gradient conditions with FID. The formic acid peak was well separated from all other solvents that are used in synthesis of particular drug substance. The LOD and LOQof the method for formic acid are 82 ppm and 249 ppm respectively. Formic acid are low toxic class-III solvent as per ICH guideline.

scholarly journals Production of ammonia makes Venusian clouds habitable and explains observed cloud-level chemical anomalies

2021 ◽  
Vol 118 (52) ◽  
pp. e2110889118
Author(s):  
William Bains ◽  
Janusz J. Petkowski ◽  
Paul B. Rimmer ◽  
Sara Seager
Keyword(s):  
Sulfuric Acid ◽  
Atmospheric Models ◽  
Cloud Droplets ◽  
Lower Cloud ◽  
Large Particles ◽  
Ammonium Sulfite ◽  
Unknown Composition ◽  
Concentrated Sulfuric Acid ◽  
Chemical Anomalies

The atmosphere of Venus remains mysterious, with many outstanding chemical connundra. These include the unexpected presence of ∼10 ppm O2 in the cloud layers, an unknown composition of large particles in the lower cloud layers, and hard to explain measured vertical abundance profiles of SO2 and H2O. We propose a hypothesis for the chemistry in the clouds that largely addresses all of the above anomalies. We include ammonia (NH3), a key component that has been tentatively detected both by the Venera 8 and Pioneer Venus probes. NH3 dissolves in some of the sulfuric acid cloud droplets, effectively neutralizing the acid and trapping dissolved SO2 as ammonium sulfite salts. This trapping of SO2 in the clouds, together with the release of SO2 below the clouds as the droplets settle out to higher temperatures, explains the vertical SO2 abundance anomaly. A consequence of the presence of NH3 is that some Venus cloud droplets must be semisolid ammonium salt slurries, with a pH of ∼1, which matches Earth acidophile environments, rather than concentrated sulfuric acid. The source of NH3 is unknown but could involve biological production; if so, then the most energy-efficient NH3-producing reaction also creates O2, explaining the detection of O2 in the cloud layers. Our model therefore predicts that the clouds are more habitable than previously thought, and may be inhabited. Unlike prior atmospheric models, ours does not require forced chemical constraints to match the data. Our hypothesis, guided by existing observations, can be tested by new Venus in situ measurements.

Determination of Gibberellic Acid Residues on Fruits by Synchronous Scanning Derivative Spectrofluorometry

1986 ◽  
Vol 69 (1) ◽  
pp. 105-109
Author(s):  
C Cruces Blanco ◽  
F García Sánchez
Keyword(s):  
Sulfuric Acid ◽  
Plant Growth ◽  
Gibberellic Acid ◽  
Dynamic Range ◽  
Fluorometric Method ◽  
Linear Dynamic ◽  
Concentrated Sulfuric Acid ◽  
The Common ◽  
Second Derivative Method

Abstract A synchronous derivative spectrofluorometric method is described for the determination of the plant growth regulator, gibberellic acid (GA3). The method is based on the formation of a fluorogen in concentrated sulfuric acid. The reaction is carried out at 85% sulfuric acid and in aqueous medium. The common fluorometric method with a linear dynamic range of 137-400 ppb, and a detection limit of 48 ppb is described. The synchronous first and second derivative method has linear dynamic ranges between 7.6-40 ppb and 12-40 ppb, with detection limits of 3.5 and 6.7 ppb, respectively. The influence of reaction variables and of other plant growth regulators present, and the application to residues on oranges, lemons, and grapes, are also described.

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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