ascorbic-acid and sulfuric-acid

To explore the effects in normal and asthmatic adults of exposure to 200 ppb sulphur dioxide (SO2) and 200 microg/m3 and 2000 microg/m3 aerosols of ammonium bisulphate (AB) and sulphuric acid (SA) (MMD 0.3 microm).. Exposures were placebo controlled, for one hour at rest, double blind in random order. DeltaFEV1 was the primary outcome; secondary outcomes included symptoms, ventilation, exhaled nitric oxide (NO) concentrations, and nasal lavage fluid ascorbic (AA) and uric acid (UA) concentrations.. There were no significant changes in spirometry or symptoms with any exposure in either group. SO2 exposure was associated with an increased respiratory rate relative to air exposure in the asthmatic group (SO2: 958.9 breaths/hour; air: 906.8 breaths/hour) but the mean volume breathed did not differ significantly (SO2: 318.8 litres; air: 311.4 litres). AB exposures were associated with a significant rise in [NO] in the asthmatic (+1.51 ppb, and +1.39 ppb), but not in the normal group. Mean pre- and post-exposure [AA] tended to be higher in the normal than in the asthmatic group. Within each group, [AA] did not change significantly with any exposure. Post-exposure [UA] were greater than pre-exposure concentrations for all exposures, significantly so in the normal group for all exposures except SO2. There were no significant differences in the mean change in [UA] for any exposure relative to air.. The pollutant exposure concentrations employed in this study were generally much greater than ambient. It is unlikely that short lived exposures at lower concentrations would show significant effects, but effects of longer term lower concentration exposures cannot be ruled out.

Topics: Adult; Air Pollutants; Ammonium Sulfate; Antioxidants; Ascorbic Acid; Asthma; Double-Blind Method; Female; Forced Expiratory Volume; Humans; Male; Nasal Mucosa; Nitric Oxide; Sulfur Dioxide; Sulfuric Acids; Uric Acid

The main objective of this study was to investigate the effects of reductive acidic leaching and further precipitation on the recovery of manganese and zinc from spent alkaline and zinc-carbon battery powders. Ascorbic acid (AA), citric acid (CA) and oxalic acid (OA) were tested as the reductants. Sodium hydroxide and potassium hydroxide were used as precipitating agents. OA with H(2)SO(4) or HCl was not effective on the leaching of zinc due to the formation of zinc oxalate precipitates. However, the other reducing agents (CA and AA) tested under various experimental conditions were effective in the acidic leaching of both zinc and manganese. Leaching yields of both manganese and zinc were higher at leach temperature of 90 degrees C than those at 30 degrees C. Leach solutions were purified by the selective precipitation of manganese and zinc using KOH or NaOH. Complete precipitation was obtained for Mn at pH 9-10 and for Zn at pH 7-8. The use of ascorbic acid or citric acid as reductants in acidic leaching appears to be effective in the simultaneous leaching and further recovery of zinc and manganese from spent alkaline and zinc-carbon battery powders.

Topics: Acids; Analysis of Variance; Ascorbic Acid; Electric Power Supplies; Industrial Waste; Manganese; Powders; Reducing Agents; Refuse Disposal; Sulfuric Acids; Temperature; Thermodynamics; Water Pollutants, Chemical; X-Ray Diffraction; Zinc

A simple and rapid method for determination of intentional contamination with heavy metals in foods using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) has been developed. The heavy metals were extracted with sulfuric acid in a disposable tube using a homogenizer. The extract was diluted with 1% HNO(3) solution and analyzed with ICP-AES. Recovery tests of 9 metals, As, Cd, Cr, Hg, Mn, Pb, Sb, Sn, and Tl, from 12 foods were performed, and gave acceptable recovery (71-107%) with low relative standard deviation (1-11%). The time required for conversion of 12 samples to test solutions was approximately 2 hr. This method could be useful for identification of heavy metals involved in food poisoning cases.

Topics: Ascorbic Acid; Emergencies; Food Analysis; Food Contamination; Heavy Metal Poisoning, Nervous System; Humans; Metals, Heavy; Spectrophotometry, Atomic; Sulfuric Acids; Time Factors

A highly sensitive spectrofluorimetric method is proposed for the determination of trace amount of ascorbic acid using a new indication. The method is based on the inhibition of ascorbic acid on the oxidation of pyronine Y (PRY) by nitrite. The detection limit for ascorbic acid is 0.012 microg ml(-1), the linear range of the determination is 0.02-0.36 microg ml(-1). Analytical parameters, such as reagent concentration, pH, reaction temperature and time, were optimized. The relative standard deviations of eleven replication determinations of 0.12 and 0.24 microg ml(-1) ascorbic acid were 1.4 and 0.72%, respectively. This method has been used to determine ascorbic acid in pharmaceuticals, vegetables, fruits and soft drink with satisfactory results.

Topics: Ascorbic Acid; Nitrites; Pyronine; Spectrometry, Fluorescence; Sulfuric Acids; Time Factors

An original, simple and sensitive flow-injection spectroelectroanalytical method for the determination of chlorpromazine in pure form or in pharmaceutical formulations is described. The method is based on the formation of a stable cationic radical by electro-oxidation in sulfuric acid medium (0.1 mol l(-1)), monitored in situ at lambda=524 nm. The determination of chlorpromazine hydrochloride in pure form or in pharmaceutical formulations was explored, considering the amperometric and the absorptiometric signal. The association of these two signals enhanced the selectivity of the analysis and proved decisive when other electroactive compounds or excipients like ascorbic acid were present in the formulation. The analytical parameters have been evaluated and the results obtained using standard additions are in agreement with the reference methods.

Topics: Antipsychotic Agents; Ascorbic Acid; Chlorpromazine; Electrochemistry; Flow Injection Analysis; Oxidation-Reduction; Sulfuric Acids

A simplified method for inorganic phosphate determination has been developed. The method is sensitive, easy, economic, and applicable for estimation of phosphate released in both enzymatic and nonenzymatic reactions. A mixture of hydrazine sulfate and ascorbic acid was used as the reducing agent and the conditions for the development of the molybdenum blue color were optimized. Thus in the 4.0 ml assay system, 0.4 ml of the reducing agent solution containing 20 mg each of hydrazine sulfate and ascorbic acid per milliliter of 1.0 N H2SO4 gave a rapid optimum color development with absorption maximum at 820 nm. Color development showed a linear relationship up to 10 microg Pi concentration. Thus the method has a 2.5x higher range of Pi estimation than that of the Bartlett method. The molar extinction coefficient at 820 nm was higher than that obtained in the Bartlett procedure. Also the molybdenum blue color formed was stable up to 24 h. Under the standard assay conditions, interference from acid-labile phosphate as in the case of Na+,K+ ATPase was at the minimum. The applicability of the method for assay of microsomal Na+,K+ ATPase and glucose-6-phosphatase was checked in microassays (final volume 0.1 ml) in comparison to the conventional procedures which use 3-4 times higher volumes. Likewise the applicability of the method for phospholipid analysis was compared with that of the conventional Bartlett method. Under both test systems the results obtained by the micromethod were identical to those obtained by the conventional methods. In general the method, which rapidly produces quantitatively molybdenum blue color, not only is rapid economical, and convenient but also has wide applicability.

Topics: Animals; Ascorbic Acid; Color; Glucose-6-Phosphatase; Hydrazines; Liver; Molybdenum; Oxidation-Reduction; Phosphates; Phosphoric Monoester Hydrolases; Rats; Sodium-Potassium-Exchanging ATPase; Sulfuric Acids

Topics: 3,3'-Diaminobenzidine; Ascorbic Acid; Carcinogens; Potassium Permanganate; Sulfuric Acids; Waste Disposal, Fluid

A simple specific method for the determination of vitamin C has been investigated by elucidating the reaction mechanism of its oxidation with cerium(IV) in sulphuric acid media. The reaction kinetics and rate measurements which form the basis of this method were determined by following the decrease of the intense yellow colour of cerium(IV) at 405 nm. The fixed-time and fixed-concentration methods were investigated. The former was found to be more precise and was consequently used for the determination. Advantages of this method over the B.P. and other methods are discussed.

Topics: Ascorbic Acid; Cerium; Chemistry, Pharmaceutical; Hydrogen-Ion Concentration; Kinetics; Oxidation-Reduction; Spectrophotometry; Sulfuric Acids; Thermodynamics

Topics: Animals; Ascorbic Acid; Cell Line; Cricetinae; Cricetulus; Humans; Liver; Methods; Mice; Molybdenum; Perchlorates; Phospholipids; Rats; Sulfuric Acids