Development of a method for the determination of chlorine in oil prepared by emulsion via MgCl molecule by HR-CS MAS
Chlorine, petroleum, emulsion, molecule, HR-CS MAS
A methodology for the determination of chlorine in petroleum samples prepared by emulsions was developed by high resolution molecular absorption spectrometry with continuum source through the diatomic molecule MgCl, in the wavelength 377.01 nm. The preparation of the emulsion was optimized through centroid-simplex design. The conditions of preparation of the emulsions were: 0.5 mL of 5% v / v HNO3, 0.5 mL of xylene and 2 mL of a mixture of n-Propanol / Triton* X-100 solvents in the ratio 5:1. The crude oil mass used was about 0.20 g. Magnesium metalic was used as the precursor of the molecule, the optimized concentration was 10 g L-1. The proportional studies between Mg and Cl for the formation of molecules show that to ensure the formation of a MgCl molecule is required for a mass ratio of at least 500 Mg: 1 Cl. A mass of 5 μg of Pd was introduced at each cycle that chemical modifier for increase the thermal stability of the molecular species. The optimized pyrolysis and atomization temperatures were 800 ° C and 2300 ° C, respectively. For chlorine analysis, the crude oil samples from the Potiguar Basin were used. The calibration strategy against aqueous standards was possible, obtaining the LOD of 3μg g-1. Addition / recovery tests were performed and the values obtained were between 92 and 117%, values acceptable analytically.