Determination of Magnesium and Calcium in Foods by Atomic Absorption Spectrometry after Microwave Digestion: NMKL Collaborative Study

Abstract On the basis of results of the performed collaborative study, the 49th Annual General Meeting of the Nordic Committee on Food Analysis (NMKL) in The Faroe Islands, August 1995, approved this method to be printed and included in NMKL's collection of methods of analysis of foods. Eleven...

Full description

Bibliographic Details
Published in:Journal of AOAC INTERNATIONAL
Main Authors: Julshamn, Kaare, Maage, Amund, Wallin, Harriet C, Lierhagen, S, Nielsen, J, Åsbø, E, Engman, J, Berg, H, Johansson, M-L, Liukkonen-Lilja, H, Hirvonen, A, Højgaard, A, Meyland, I, Niemi, E
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 1998
Subjects:
Online Access:http://dx.doi.org/10.1093/jaoac/81.6.1202
http://academic.oup.com/jaoac/article-pdf/81/6/1202/32459659/jaoac1202.pdf
Description
Summary:Abstract On the basis of results of the performed collaborative study, the 49th Annual General Meeting of the Nordic Committee on Food Analysis (NMKL) in The Faroe Islands, August 1995, approved this method to be printed and included in NMKL's collection of methods of analysis of foods. Eleven laboratories participated in an interlaboratory methods-performance (collaborative) study of a method for determining magnesium and calcium in foodstuffs by atomic absorption spectrometry (AAS) after wet microwave digestion. The study was preceded by a practice round of familiarization samples. The method was tested on 7 materials: 5 foods (apple, milk powder, minced fish, wheat bran, and chocolate cake) and 2 composite diets ranging in Mg content from 240 to 3900 mg/kg and in Ca content from 290 to 9300 mg/kg. The materials were presented to study participants as blind duplicates, and participants were asked to perform single determinations on each sample. Repeatability relative standard deviations (RSDr) ranged from 1.9 to 4.9% for Mg and from 2.2 to 8.1 % for Ca. Reproducibility relative standard deviations (RSDR) ranged from 4.0 to 13% for Mg and from 5.9 to 23% for Ca. For Ca, lowest RSDR values were found for samples with high concentrations of Ca (>3800 mg/kg sample) and with nitrate ion residues of <1.3% (w/v).