Chemical Analysis of Magnesia and Magnesia-Alumina Refractory Materials——Flame atomic absorption spectrometric method for determination of calcium oxide content

1 Scope This standard specifics the determination of calcium oxide coutent by flame atomic absorption spectrometric method.

Extraction-Atomic-Absorption Determination of Gallium (III) with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene

The complexation of gallium with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene (HR) has been studied by atomic absorption and spectrophotometric methods. The optimal conditions for the formation and extraction of the complex were found. The maximum light absorption of the complex in n-butanol is in the range of 450 - 470 nm. The molar absorption coefficient is (3.3 - 4.2)⋅104. The stability constant of the gallium coordination compound in n-butanol is βl = 4.2⋅1010. The developed technique allows to determine the gallium content within n × 10−1 - n × 10−4%. The selective and sensitive technique for the extraction-atomic absorption determination of gallium in soils has been developed.

Curcumin Extract as a Green Inhibitor of Leaching from Aluminum Cookware at Quasi-Cooking Conditions

Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wares were bought from the market from four countries and cut to make the Aluminum samples. Six types of vegetables and three kinds of meat were chosen. Each type of vegetable and meat was used to prepare 30% w/v aqueous solutions. Three methods were used in the present study: Gravimetric method, Atomic Absorption and FTIR. Gravimetric method was applied to determine the leaching rate and the corrosion inhibition efficiency with/without NaCl. The effect of Curcumin concentration, Tab water, immersion time, alloying elements was investigated. There was a good consistency between Gravimetric and Atomic Absorption methods. The adsorption of Curcumin on the aluminum surface was in accordance with Langmuir isotherm. The values of the adsorption constant (Kads) and the free energy of adsorption (Gadso) were calculated and discussed. FTIR spectrum indicated that Curcumin coordinated with Al3+ resulting in the formation of Al3+-Curcumin complex on the metal surface. Using a small amount of Curcumin decreased leaching from Aluminum cook wares into food by 60% - 80% depending about the type of food.