Feasibility of employing permanent chemical modifiers for the determination of cadmium in coal using slurry sampling electrothermal atomic absorption spectrometry

被引:29
作者
Bianchin, L
Nadvorny, D
da Silva, AF
Vale, MGR [1 ]
da Silva, MM
dos Santos, WNL
Ferreira, SLC
Welz, B
Heitmann, U
机构
[1] Univ Fed Rio Grande do Sul, Inst Quim, BR-91501970 Porto Alegre, RS, Brazil
[2] Univ Fed Santa Catarina, Dept Quim, BR-88080900 Florianopolis, SC, Brazil
[3] Univ Fed Bahia, Inst Quim, BR-40170290 Salvador, BA, Brazil
[4] ISAS, Dept Berlin, Inst Analyt Sci, D-12489 Berlin, Germany
关键词
electrothermal atomic absorption spectrometry; slurry sampling; cadmium determination; coal analysis; permanent chemical modifiers; background correction; high-resolution continuum source AAS;
D O I
10.1016/j.microc.2006.01.003
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
Iridium and ruthenium, alone and in combination with tungsten, thermally deposited on the platform of a transversely heated graphite tube, were investigated for their suitability as permanent chemical modifiers for the determination of cadmium in coal slurries by electrothermal atomic absorption spectrometry (ET AAS). The conventional mixed palladium and magnesium nitrates (Pd-Mg) modifiers, added in solution, were also investigated for comparison. The latter one showed the best performance for aqueous solutions, and the mixed W-Ir and W-Ru permanent modifiers had the lowest stabilizing power. All of the investigated modifiers lost some of their stabilizing power when coal slurries were investigated. The Pd-Mg modifier, pure Ir and Ru, and a mixture of 300 mu g W+200 mu g Ir could stabilize Cd at least to a pyrolysis temperature of 600 degrees C, whereas all the other combinations already failed at temperatures above 500-550 degrees C. Additional investigations of the supernatant liquid of the slurries supported the assumption that the high acid concentration of the slurries and/or a concomitant leaching out of the coal might be responsible for the reduced stabilizing power of the modifiers. The maximum applicable pyrolysis temperature of 600 degrees C was not sufficient to reduce the background absorption to a manageable level in the majority of the coal samples. High-resolution continuum source ET AAS revealed that the continuous background absorption was exceeding values of A=2, and was overlapping with the analyte signal. Although the latter technique could correct for this background absorption, some analyte was apparently lost with the rapidly vaporizing matrix so that the method could not be considered to be rugged. A characteristic mass of 1.0 pg and a detection limit of 0.6 ng g(-1) could be obtained under these conditions. (c) 2006 Elsevier B.V. All rights reserved.
引用
收藏
页码:174 / 182
页数:9
相关论文
共 35 条
[1]   SOLID SAMPLING IN ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY USING COMMERCIAL ATOMIZERS - A REVIEW [J].
BENDICHO, C ;
DELOOSVOLLEBREGT, MTC .
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY, 1991, 6 (05) :353-374
[2]  
BORGES DLG, IN PRESS MICROCHIM A
[3]   Slurry sampling for direct analysis of solid materials by electrothermal atomic absorption spectrometry (ETAAS).: A literature review from 1990 to 2000 [J].
Cal-Prieto, MJ ;
Felipe-Sotelo, M ;
Carlosena, A ;
Andrade, JM ;
López-Mahía, P ;
Muniategui, S ;
Prada, D .
TALANTA, 2002, 56 (01) :1-51
[4]   Determination of cadmium in coal using solid sampling graphite furnace high-resolution continuum source atomic absorption spectrometry [J].
da Silva, AF ;
Borges, DLG ;
Lepri, FG ;
Welz, B ;
Curtius, AJ ;
Heitmann, U .
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2005, 382 (08) :1835-1841
[5]   Determination of Ag, Pb and Sn in aqua regia extracts from sediments by electrothermal atomic absorption spectrometry using Ru as a permanent modifier [J].
da Silva, JBB ;
da Silva, MAM ;
Curtius, AJ ;
Welz, B .
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY, 1999, 14 (11) :1737-1742
[8]   ICP-MS DETERMINATION OF 45 TRACE-ELEMENTS IN WHOLE COAL USING MICROWAVE-OVEN ACID DIGESTION FOR SAMPLE PREPARATION [J].
FADDA, S ;
RIVOLDINI, A ;
CAU, I .
GEOSTANDARDS NEWSLETTER, 1995, 19 (01) :41-54
[9]   Measurements on the Zeeman-splitting of analytical lines by means of a continuum source graphite furnace atomic absorption spectrometer with a linear charge coupled device array [J].
Heitmann, U ;
Schutz, M ;
BeckerRoss, H ;
Florek, S .
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY, 1996, 51 (9-10) :1095-1105
[10]  
KINGSTON HM, 1997, AM CHEM SOC PROFESSI