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| Souza,V.; Ordine,Alberto Pires; Fraga,I. C. S.; Getrouw,Monique Audrey; Borges,P. P.; Damasceno,J. C.; Couto,P. R. G.. |
| pH is an important parameter to control the production of food, medicine, petrochemical products and others. Thus, standard reference materials used to calibrate pH meters are necessary to guarantee reliability of the measurements. The Chemical Metrology Division (Dquim) of the National Metrology Institute of Brazil (Inmetro) has as one of its missions the certification of standard reference materials. In the case of pH, it will be done by the pH primary measurement system of Inmetro, in operation at Dquim since 2003. The buffer solution of nominal pH value equal to 6.865 will be the first to be certified. The study of some measurement parameters has already been accomplished, and will lead to the improvement of the primary pH measurement. In this paper,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chemical metrology; Primary pH; Reference material. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000200013 |
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| Bayon, Germain; Birot, Dominique; Bollinger, Claire; Barrat, Jean Alix. |
| We report on an improved method for determining trace element abundances in seawater and other natural waters. The analytical procedure involves co-precipitation on iron hydroxides after addition of a Tm spike, and measurement by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). The validity of the method was assessed through a series of co-precipitation experiments, using ultra-diluted solutions of a certified rock reference material (BIR-1). Results obtained for four natural water reference materials (NASS-5, CASS-4, SLEW-3, SLRS-4) are in agreement with published working values for rare earth elements, yttrium, vanadium and, when available, for hafnium, zirconium, thorium and scandium. A set of proposed values with uncertainties... |
| Tipo: Text |
Palavras-chave: Seawater; Reference material; ICP-MS; Trace elements; Rare earth elements; Eau de mer; Materiau de reference; ICP-MS; Elements traces; Terres Rares. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00031/14189/18000.pdf |
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