title: Inductively coupled plasma mass spectrometry and standard dilution analysis applied to concentrated acids.
abstract: This work describes a procedure using the recently proposed standard dilution analysis (SDA) calibration method for the determination of As, Cr and Ni in concentrated HNO3and HCl by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). Because of the low contaminant levels, and consequently low limits of detection required for these reagents (commonly used in trace element analysis and the semiconductor industry), samples were minimally diluted. The analysis of concentrated acids can result in matrix/transport effects, which may compromise accuracy in ICP-MS determinations. High-chlorine content samples are also challenging for As and Cr determination due to the formation of polyatomic species such as40Ar35Cl+and35Cl16OH+, which overlap the only As isotope,75As+, and the main Cr isotope,52Cr+, respectively. The combination of SDA and ICP-MS/MS was evaluated to overcome matrix, transport and spectral interferences in order to increase accuracy, precision and sample throughput. The performance of SDA was compared with the traditional methods of external standard calibration (EC), internal standardization (IS), and standard additions (SA). The limits of detection for SDA were calculated as 6, 10, and 30ngL-1for As, Cr, and Ni, respectively. Recoveries for spike experiments using the new method were in the 90-114% range for all analytes. The procedure described here provides similar or even better analytical performance in comparison with EC, IS and SA.
authors: Group for Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P. O. Box 676, São Carlos, SP 13565-905, Brazil.
authors: Alex
authors: A
authors: Virgilio
authors: Agilent Technologies Brazil, Barueri, SP 06460-040, Brazil.
authors: Daniela
authors: D
authors: Schiavo
authors: Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil.
authors: Letícia M
authors: LM
authors: Costa
authors: Group for Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P. O. Box 676, São Carlos, SP 13565-905, Brazil.
authors: Joaquim A
authors: JA
authors: Nóbrega
authors: Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC 27109, USA.
authors: Bradley T
authors: BT
authors: Jones
authors: Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC 27109, USA. Electronic address: donatigl@wfu.edu.
authors: George L
authors: GL
authors: Donati
keywords: Accuracy; Concentrated acids; High sample throughput; High-purity reagents; Tandem mass spectrometry; Two-standard calibration