Determination of Mo, Zn, Cd, Ti, NiVFe, Mn, Cr and Co in crude oil using inductively coupled plasma optical emission spectrometry and sample introduction as detergentless microemulsions

被引:83
作者
de Souza, RM [1 ]
Meliande, ALS [1 ]
da Silveira, CLP [1 ]
Aucélio, RQ [1 ]
机构
[1] Pontificia Univ Catolica Rio de Janeiro, Dept Chem, BR-22453900 Rio De Janeiro, Brazil
关键词
pneumatic nebulization; inductively coupled plasma atomic emission; crude oil; detergentless microemulsions; trace elements;
D O I
10.1016/j.microc.2006.01.005
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
A procedure to prepare crude oil samples as detergentless microemulsions was optimized and applied for the determination of Mo, Zn, Cd, Si, Ti, Ni, V, Fe, Mn, Cr and Co by ICP OES. Propan-l-ol was used as a co-solvent allowing the formation of a homogeneous and stable system containing crude oil and water. The optimum composition of the microemulsion was crude oil/propan-l-ol/water/concentrated nitric acid, 6/70/20/4 w/w/w/w. This simple sample preparation procedure together with an efficient sample introduction (using a Meinhard K3 nebulizer and a twister cyclonic spray chamber) allowed a fast quantification of the analytes using calibration curves prepared with analyte inorganic standards. In this case, Sc was used as internal standard for correction of signal fluctuations and matrix effects. Oxygen was used in the nebulizer gas flow in order to minimize carbon building up and background. Limits of detection in the ng g(-1) range were achieved for all elements. The methodology was tested through the analysis of one standard reference material (SRM NIST 1634c, Residual Fuel Oil) with recoveries between 97.9% and 103.8%. The method was also applied to two crude oil samples and the results were in good agreement with those obtained using the acid decomposition procedure. The precision (n=3) obtained was below 5% and the results indicated that the method is well suited for oil samples containing low concentrations of trace elements. (c) 2006 Elsevier B.V. All rights reserved.
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页码:137 / 141
页数:5
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