Homogeneity and stability studies during the preparation of a laboratory reference material of soy leaves for the determination of metals.
The homogeneity and stability of metals were tested in a candidate laboratory reference material of soy leaves. Inductively coupled plasma-optical emission spectrometry was used to quantify calcium, magnesium, manganese, iron, zinc, copper, and vanadium. A 6 kg amount of the material, which was dried, ground, and classified as mesh 60, was distributed among 100 bottles. The between-bottle homogeneity test was established by analyzing two subsamples from nine bottles. For the within-bottle test, five determinations of each element of a single bottle were performed. The stability test was performed at temperatures of -10, +27, and +40 degrees C, and after storage times of 4, 12, 24, and 52 weeks. The obtained results indicated that the material was homogeneous and stable under the conditions studied.
Universidade Federal da Bahia, Instituto de Química, Grupo de Pesquisa em Química e Quimiometria 40170-290, Salvador, Bahia, Brazil. amps@ufba.br
Ana M P
AM
dos Santos
Daniel C
DC
Lima
Robson M
RM
de Jesus
Sergio L C
SL
Ferreira
D002118:Calcium / Q000032:analysis / Q000592:standards; D018515:Plant Leaves / Q000737:chemistry*; D012015:Reference Standards; D013025:Glycine max / Q000737:chemistry / Q000592:standards; D013054:Spectrophotometry, Atomic; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis / Q000592:standards
D014131:Trace Elements; D002118:Calcium