Carbonates, analysis gravimetric

An alternative method for the same analysis rises nltrasonic extraction. Tested materials are placed in a container containing the test flnid in ultrasonic bath for controlled amount of time (usually 10 min) and at a controlled temperature. The type of ultrasonic bath and conditions of its operation has snbstantial inflnence on the result. Extracted material can be determined by several methods such as gravimetric, used after evaporation of solvent, liquid chromatography, or total carbon analysis. 

Method by analysis of evolved carbon dioxide. Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test. 

The heavy metal salts, ia contrast to the alkah metal salts, have lower melting points and are more soluble ia organic solvents, eg, methylene chloride, chloroform, tetrahydrofiiran, and benzene. They are slightly soluble ia water, alcohol, ahphatic hydrocarbons, and ethyl ether (18). Their thermal decompositions have been extensively studied by dta and tga (thermal gravimetric analysis) methods. They decompose to the metal sulfides and gaseous products, which are primarily carbonyl sulfide and carbon disulfide ia varying ratios. In some cases, the dialkyl xanthate forms. Solvent extraction studies of a large number of elements as their xanthate salts have been reported (19). 

Gravimetric analysis, carbon black, quartz, silica... 

CO2 ( fixed air ), prepared by Joseph Black (aged 24-26), was the first gas other than air to be characterized (i) chalk when heated lost weight and evolved CO2 (genesis of quantitative gravimetric analysis), and (ii) action of acids on carbonates liberates CO2. 

MDHS 14 General method for the gravimetric determination of respirable and total dust MDHS 15 Carbon disulphide MDHS 16 Mercury vapour in air Laboratory method using hopcalite adsorbent tubes, and acid dissolution with cold vapour atomic absorption spectrometric analysis MDHS 17 Benzene in air Laboratory method using charcoal adsorbent tubes, solvent desorption and gas chromatography MDHS 18 Tetra alkyl lead compounds in air Continuous on-site monitoring method using PAC Check atomic absorption spirometry... 

Cadmium and inorganic compounds of cadmium in air (X-ray fluorescence spectroscopy) Chromium and inorganic compounds of chromium in air (atomic absorption spectrometry) Chromium and inorganic compounds of chromium in air (X-ray fluorescence spectroscopy) General methods for samphng and gravimetric analysis of respirable and inhalable dust Carbon disulphide in air... 

A similar method for determination of graphite and carbon black is described in Std Methods of Chem Analysis (Ref 3) under the title "Carbon Black and Graphite, Gravimetric". It is not included here because it is assumed that every diem lab has a. copy of Std Methods... 

A historically important form of gravimetric analysis was combustion analysis, used to determine the carbon and hydrogen content of organic compounds burned in excess 02 (Figure 27-4). Instead of weighing combustion products, modem instruments use thermal conductivity, infrared absorption, or coulometiy (with electrochemically generated reagents) to measure the products. 

Figure 27-4 Gravimetric combustion analysis for carbon and hydrogen.

Thermal gravimetric analysis of diaryl tellurium diacetates indicated that carbon dioxide was released by these molecules with formation of diaryl dimethyl telluriums4. 

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