Internal standard addition calibration: Determination of calcium and magnesium by atomic absorption spectrometry

Author(s)

Fortunato, Felipe Manfroi ^[1] ; Bechlin, Marcos A. ^[1] ; Gomes Neto, Jose A. ^[1] ; Donati, George L. ^[2] ; Jones, Bradley T. ^[2]

Affiliation

^[1] Sao Paulo State Univ, UNESP, Dept Analyt Chem, BR-14801970 Araraquara, SP - Brazil

^[2] Wake Forest Univ, Dept Chem, Winston Salem, NC 27109 - USA

• Document type: Journal article
• Source: Microchemical Journal; v. 122, p. 63-69, SEP 2015.
• Web of Science Citations: 9

Abstract

Internal standard addition (ISA) is a new calibration method that combines the principles of internal standardization and standard additions. The current work demonstrated the effectiveness of ISA for the determination of Ca and Mg in biodiesel samples and certified reference materials (CRMs) by flame atomic absorption spectrometry. Manganese and Sr were selected as internal standards for Mg and Ca, respectively. Results for Ca and Mg in CRMs using ISA were in agreement with certified values at the 95% confidence level (t-test). The relative standard deviations (n = 12) were ca. 6% for both analytes. For comparison purposes, Ca and Mg were also determined by the traditional methods of external standard calibration (ES), standard additions (SA) and internal standardization (IS). Recoveries obtained with ISA (Ca: 93-109%; Mg: 100-106%) were similar to those found with IS (Ca: 100-112%; Mg: 98-105%), but significantly better than ES (Ca: 219-291%; Mg: 111-120%) and SA (Ca: 97-127%; Mg: 106-128%). Results for Ca and Mg determined in biodiesel and CRMs using ISA were more accurate and more precise than those obtained with ES, SA and IS. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/23323-7 - Internal standard addition method using flowing gradient concentration in spectroscopic techniques
• Grantee: Felipe Manfroi Fortunato
• Support Opportunities: Scholarships in Brazil - Doctorate