Sulfur quantitative analysis

Recovery of Organic Sulfur. Quantitative analysis can be accomplished provided that all the sulfur present in the form of each group is reduced to H2S. It is also assumed that the distribution does not change during the analysis and that all the H2S released is detected and determined. 

The quantitative analysis procedure involves gravimetric detn of the HMX on a moisture-free basis after benzene extraction of, and differential detn of TNT. Moisture content is detd by conductometric titration of sample in an acetic-sulfuric acid suspension. Acetone insoluble matter is determined gravimetrically... 

The applications of EPR spectroscopy reviewed in the present chapter are based on the sensitivity of the spectrum displayed by iron-sulfur centers to various characteristics, such as the redox state of the center, the distribution of the valences on the iron ions, the nature and the geometry of the ligands, and the presence of nearby paramagnetic species. Although considerable progress has been made during the past few years in the quantitative analysis of these various effects in the case of the conventional iron-sulfur centers described in Section II, the discovery of centers exhibiting unusual EPR properties as... 

It is of interest to examine the development of the analytical toolbox for rubber deformulation over the last two decades and the role of emerging technologies (Table 2.9). Bayer technology (1981) for the qualitative and quantitative analysis of rubbers and elastomers consisted of a multitechnique approach comprising extraction (Soxhlet, DIN 53 553), wet chemistry (colour reactions, photometry), electrochemistry (polarography, conductometry), various forms of chromatography (PC, GC, off-line PyGC, TLC), spectroscopy (UV, IR, off-line PylR), and microscopy (OM, SEM, TEM, fluorescence) [10]. Reported applications concerned the identification of plasticisers, fatty acids, stabilisers, antioxidants, vulcanisation accelerators, free/total/bound sulfur, minerals and CB. Monsanto (1983) used direct-probe MS for in situ quantitative analysis of additives and rubber and made use of 31P NMR [69]. 

Kjeldahl method analychem Quantitative analysis of organic compounds to determine nitrogen content by interaction with concentrated sulfuric acid ammonia Is distilled from the Nff4S04 formed. kel,dal, meth-ad )... 

The area under a chromatographic peak is proportional to the concentration of the corresponding.species in the sample analysed. Using empirical calibration functions, a rapid simultaneous qualitative and quantitative analysis of sulfur mixtures by HPLC is now possible. In a similar manner the selenium rings Seg, Se, and SCg have recently been separated by HPLC... 

Inorganic quantitative analysis of sugar cane juice, vinasse, and molasses. 1. Calcium, magnesium, potassium, sulfur and phosphorus determination in single ex- SO099 tract. An Esc Super Agr Luiz Dr Queiroz Univ Sao Paulo 1972 29 5. 

Brandt published a description of this mineral in the volume of the Acta of die Upsala Academy for 1742 and in Vetenskapsacademiens Handlingarna for 1746, and mentioned that it contains cobalt, iron, and sulfur, but that, unlike ordinary cobalt glance, it is free from arsenic. When W. von Hisinger made a quantitative analysis of it m 1810, he found it to be cobalt sulfide. This mineral is now known as linnaeite its formula is CosS4, in which part of the cobalt may be replaced by nickel, iron, or copper. 

Carl Friedrich Plattner was bom in 1800 at Klein-Waltersdorf near Freiberg, was educated at the Freiberg School of Mines, and became a professor of metallurgy and blowpipe analysis there. He was a great master of the art and science of analytical chemistry, and applied the blowpipe even to quantitative analysis. He made many promising experiments on the oxidation of sulfur dioxide to the trioxide by means of catalysts. Before the work was completed, however, he was stricken with apoplexy, which terminated fatally in 1858 (68). When F lix Pisani (1831—1920) examined pollucite four years after the discovery of cesium, he found that Plattner had mistaken his cesium sulfate for a mixture of the sulfates of sodium and potassium (8, 37, 58). 

Elements of Quantitative Analysis," Van Nostr and,NY( 1956) 234-5(Available oxygen in MnOa is detd by heating a sample in dil sulfuric acid soln with a known wt of Na oxalate until the dioxide has dissolved ... 

Sulfur is a reactive oxidizing agent. Hence, some precautions need to be observed in its removal from coal and in its quantitative measurement. Recent contributions have discussed several different methods for its quantitative analysis (4-9). The results for two coal samples, one a pristine sample of Illinois No. 6 coal, APCSP-3, and the other an exposed sample of Illinois No. 6 coal, IBCSP-1, are summarized in Table III. 

Qualitative Analysis. High-resolution MS generally can separate and identify the formulas of essentially all heteroaromatic components containing one or more oxygen, sulfur, and nitrogen atoms per molecule, although some difficulties remain in the routine identification of sulfur compounds. The approach used to compensate for the latter difficulty is discussed in the section on quantitative analysis. 

The tin scrubber must be conditioned to sulfur, nitrogen, and chlorine before quantitative analysis can be achieved. A solution containing 10 mg/kg butyl sulfide, 100 mg/kg pyridine, and 200 mg/kg chlorobenzene in isooctane has proven... 

ORNL also considered calculating an SF on the basis of the U.S. Environmental Protection Agency s (EPA 1991) estimated inhalation unit risk (8.5 x 10 per pg/m ) of sulfur mustard. Normalizing the inhalation unit risk for a 70-kg person inhaling 20 m of air per day would yield an SF of 0.3 per pg/kg per day. ORNL decided not to use this method because the inhalation study (McNamara et al. 1975) used to estimate the inhalation unit risk resulted in rat skin tumors that appeared to be caused by dermal exposure rather than by systemic absorption and distribution to the skin, and inhalation-to-oral extrapolation was not considered appropriate. Furthermore, the McNamara et al. (1975) study contained a number of deficiencies, such as outdated testing protocols, brief exposures, and small numbers of animals, which made quantitative analysis difficult. 

U.S. EPA (1991) derived a cancer inhalation unit risk for sulfur mustard based on the results of inhalation animal studies conducted by McNamara et al. (1975, see Section 3.7.2) however, it was emphasized in the EPA report that the studies of McNamara et al. (1975) contained deficiencies which made a quantitative analysis difficult. Conducted in 1970, the studies do not conform to the modem norms of acceptable experimental protocol, and it is likely that there was bias in the assignment of the animals to the test categories (U.S. EPA, 1991). In addition, many of the exposures were very brief, included only a few animals, and many of the animals were sacrificed (and some were replaced) before their capacity to develop late-appearing tumors was fully developed (U.S. EPA, 1991). Despite these shortcomings, it was noted by EPA that the McNamara et al. data are the best available for estimating the carcinogenic potency of sulfur mustard. The authors of the EPA report analyzed two sets of McNamara s data one from a toxicity study and one from a carcinogenicity study (see Section 3.7.2). 

During the fifteenth century the metals zinc, antimony, bismuth, and probably cobalt were discovered, together with many new reactions now used in quantitative analysis. For example, A. Libavius (1540-1616) noted how ammonia in water could be determined by the blue color formed with a copper salt. Robert Boyle (1627-1691) was the first to use a solution of hydrogen sulfide (which he made from flowers of sulfur, potash, and ammonium chloride) as an analytical reagent, and he noted the black precipitate it formed with lead, gold, and mercury. 

The use of MRM methods for quantitative bioanalysis often reduces sample preparation and analysis time. The MRM method that used LC/ESI-MS/MS for the quantitative analysis of an anticancer drug, Yondelis (Ecteinascidin 743, ET-743, trabectedin. Scheme 9), in human plasma was demonstrated by Rosing et al. [103]. The full-scan mass spectrum of ET-743 (MW 762) contained an abundant [MH+ - H2O] ion at m/z 744 as a result of loss of water molecules from in-source CID (spectrum not shown). The internal standard, ET-729 (Scheme 9, MW 747), exhibited similar performance in the full-scan mass spectrum an abundant [MH+ - H2O] ion at tn/z 730 was produced. The product ion spectra of ET-743 and ET-729 exhibited the most abundant fragment ions at m/z 495 and m/z 479, respectively (spectra not shown). The product ion at m/z 495 (C27H31N2O7) was formed in the collision cell after cleavage of the sulfur bond and ester binding at C-11 [103]. 

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