Oxygen analytical determination

A number of analytic determinations of reaction products by taking samples as described above have been made. The results show, that the oxygen consumption in the flame is nearly complete, with CO2 and CO as major products. At temperatures below flame ignition, cold combustion was also detected with a similar range of products. 

In our study, contact of the anoxic samples with oxygen was avoided. The samples were transferred from the samplers (Go-Flo, General Oceanics, 5 L) into bottles equipped with three-way taps under N2 pressure. The bottles had previously been flushed with N2, and they were completely filled. Filtration in the laboratory with acid-cleaned 0.45- xm cellulose nitrate filters (Sartorius) and a polycarbonate filtration unit (Sartorius) was also carried out under nitrogen gas. Most analytical determinations were performed in the laboratory on the sampling day. 

Amino acids Building blocks of protein by cells there are about 20 amino acids Ames test A method of an experiment performed using bacteria as a test system to determine the mutagenic potential of a substance or chemical Anaerobic Requiring the absence of oxygen Analyte Any chemical substance measured in the laboratory Analytic epidemiologic study A study that evaluates the association between exposure to hazardous chemical substances and disease by testing scientific hypotheses... 

Empirical formulas for the products from each melt system were obtained we assumed that oxygen was the other constituent of the compounds. The elemental ratios are subject to some variation because of uncertainties in the analytical data. The uranium analyses are estimated to be valid within 2%. Independent analytical determinations have shown that the original uranium dioxide contained approximately 0.5% iron, plus a trace of silica. Adjustment of the analytical data for these minor impurities was not done. 

Other major shale constituents such as C, H, N, and S are determined by thermal decomposition and instrumental detection methods. Oxygen is determined by 14 MeV neutron activation analysis. Parr or Leco BTU bomb combustion and subsequent ion chromatographic determination is used for halogens, sulfate and nitrate. Ion chromatography is also suitable for anionic characterization of shale process waters. Two analytical procedures for oil shales should be used with caution. Kjeldahl nitrogen procedure has been found to give reproducible but considerably low results for certain oil... 

Relatively inexpensive portable colorimetric indicators are now commonly used to detect the presence of a variety of contaminant gases in the atmosphere. These are normally specific for one or perhaps a series of gases. For example, the NBS colorimetric detector uses an indicator tube that contains a 15-mm section of yellow palladous silico-molybdate gel the gel changes color when exposed to carbon monoxide at concentrations as low as 0.001 vol. % in air. Figure 52 shows one version of a commercial unit used for carbon monoxide as well as carbon dioxide, the unsaturated hydrocarbons, and a variety of other gases this unit can also be used to determine the approximate concentrations of contaminants in liquid oxygen. Precise determinations can be made with a variety of analytical tools, including infrared... 

Graphical and analytical determination of the corrosion current is explained in detail in Chapter 3. The Evans diagram for an iron system in an oxygen-saturated solution with a pH of 7 is shown in Fig. 1.2. 

The analytical determination of D-glucose in molasses has been achieved using a microbial electrode consisting of Pseudomonas fluorescens cells co-cast with collagen onto an oxygen electrode. ... 

Warm-Up Example 4. A reactor is fed with a mixture of oxygen (O2) and propane (CsHg). Oxygen is in excess and the conversion of the reaction is 70 %. At the output of the reactor, the presence of 21 [mol] of CO2 and 40 [mol] of O2 has been analytically determined, (a) What is the fractional excess of oxygen (b) How many moles of propane were fed to the reactor (c) What is the molar composition of the output stream ... 

The aim of the present work is to estimate the linear voltammetry possibilities in oxide-ion analytical determination in FLINAK melt with and without addition of tantalum and boron complex fluorides. Sodium oxide was used as a source of oxygen in the melts. 

The colorless, vacuum-distillable liquid [(2,2-dimethylpropanoyl)oxy]diethyl-borane (2,2-dimethylpropanoyl = pivaloyl) is a catalyst for the introduction of diethylboryl groups onto the oxygen atoms of hydroxy compounds using tri-ethylborane, Diethylborylations of hydroxy compounds have both preparative " and analytical (determination of the ethane value EZ ) uses. [(2,2-Dimethylpropanoyl)oxy]diethyIborane is itself a reagent for preparing aldol-condensation products" and for determining analytical pivalate values (PZ) of H-acidic compounds. ... 

One of the major problems in studies of O2 production from water has heen analytical determination of the O2 generated. Due to its very high solubility, up to saturation levels, 0 tends to remain in solution and chromatographic determination of gas samples over the solution often prove inadequate. Valenty has suggested use of a double-column for direct injection of the aqueous sample into the GLC. Detection of small quantities of O2 in situ with the aid of a dark oxygen electrode (with the reaction mixture standing over the... 

It should be noted that, above about 1600°C, oxygen is released from the Nb-0 or Ta-0 mixed crystals in the form of the volatile oxides NbO and Nb02 or TaO and Ta02, respectively (48) however, this process is of no importance in connection with the analytical determination of oxygen. 

Ion-selective electrodes can be used for analytical determinations over an extremely wide range of solution concentrations (from 10" to 10 M to saturation) and are therefore applicable to trace as well as to major-constituent analysis. There are presently about two dozen ion-selective electrodes commercially available for cations, including the heavy metals for anions such as fluoride, sulfide, and the halides and for gases such as oxygen, carbon dioxide, and ammonia. ... 

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