Hazard, sulfur analysis

Reference methods for criteria (19) and hazardous (20) poUutants estabHshed by the US EPA include sulfur dioxide [7446-09-5] by the West-Gaeke method carbon monoxide [630-08-0] by nondispersive infrared analysis ozone [10028-15-6] and nitrogen dioxide [10102-44-0] by chemiluminescence (qv) and hydrocarbons by gas chromatography coupled with flame-ionization detection. Gas chromatography coupled with a suitable detector can also be used to measure ambient concentrations of vinyl chloride monomer [75-01-4], halogenated hydrocarbons and aromatics, and polyacrylonitrile [25014-41-9] (21-22) (see Chromatography Trace and residue analysis). 

Precautions are necessary to prevent explosions when using the mixed acids to oxidise organic materials for subsequent analysis. The sulfuric acid probably tends to dehydrate the 70% perchloric acid to produce the hazardous anhydrous acid. See Nitric acid, etc., above... 

Organic materials, Sulfuric acid Analytical Methods Committee, Analyst, 1976, 101, 62-66 Advantages and potential hazards in the use of mixtures of 50% hydrogen peroxide solution and cone, sulfuric acid to destroy various types of organic materials prior to analysis are discussed in detail. The method is appreciably safer than those using perchloric and/or nitric acids, but the use of an adequate proportion of sulfuric acid with a minimum of peroxide is necessary to avoid the risk of explosive decomposition. The method is not suitable for use in pressure-digestion vessels (PTFE lined steel bombs), in which an explosion occurred at 80° C. 

Precaution Violent reaction with organic matter explosive reactions possible Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of l and K2O HMIS Health 1, Flammability 0, Reactivity 3 Uses Analysis (testing for zinc and arsenic) iodometry reagent food additive (dough conditioner, flour treatment agent) feed additive (trace mineral) medicine (topical antiseptic) oxidation of sulfur dyes Regulatory FDA 21 CFR 136.110, 184.1635, 582.80, GRAS... 

Chemicals used in the quality control analyses in the shieided glove box (SGB) and ventilation hoods of the Quality Control Laboratory involve small (less than a liter) quantities of some acidic and basic chemicals, including ammonium thiocyanate, stannous chloride, sulfuric, nitric, and hydrochloric acids, ferric sulfate, carrier solutions, ethyl acetate, sodium nitrite, chloroform, sodium hydroxide, and potassium iodide. Material Safety Data Sheets for any processes implemented in the HCF are reviewed in accordance with the SNL ES H Manual to identify any carcinogens or other hazardous materials. Operations in the SGB for preparation of various Mo-99 product dilution samples would require a small bulk supply of sodium hydroxide (0.1 N NaOH). Quality control analysis sample preparation operations require small bulk supplies of the above chemicals. Workers performing quaiify control analysis use chemical handling procedures as required by the Sandia ES H Manual. 

Ho KL, Chung YC, Lin YH, Tseng CP (2008) Microbial populations analysis and field application of biofilter for the removal of volatile-sulfur compounds from swine wastewater treatment system. J Hazard Mater 152 580-588... 

Several methods including spectrophotometric or chromatographic techniques have been proposed for the determination of furans such as HMF or furfural, or developed to determine both furan compounds simultaneously. The spectrophotometric methods do not differentiate between HMF and furfural without the need of a previous separation procedure. The commonly employed colorimetric method for HMF is Winkler s 38), which is based on the use of barbituric acid and p-toluidine. Toxicity of p-toluidine, instability of the color complex formed, and interference of sulfurous acid and possibly other compounds present in the fruit juice 40) are known to be problems. Unlike HMF, the colorimetric method for furfural was based on a previous distillation of juice and the colorimetric analysis of distillate for furfural based on colorimetric reaction with aniline acetic acid in juices 41). However, distillation procedure with poor recovery (about 34%) and long reaction time for color development (approximately 1 h), and requirement of hazardous chemical aniline 20) are known to be the drawbacks of the colorimetric method for furfural. Also, colorimetric method generally requires strict control of reaction time and temperature to achieve stable and reproducible color development. 

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