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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Analysis of inorganic constituents in milk and simulation of CFA-C reagent

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Author(s):
Daniele Minholo Santos [1] ; Ana Rita Araujo Nogueira [2] ; Eduardo Fausto Almeida Neves [3] ; Éder Tadeu Gomes Cavalheiro [4] ; Joaquim Araújo Nóbrega [5]
Total Authors: 5
Affiliation:
[1] UFSCar. Departamento de Química - Brasil
[2] EMBRAPA. Embrapa Pecuária Sudeste - Brasil
[3] UFSCar. Departamento de Química - Brasil
[4] UFSCar. Departamento de Química - Brasil
[5] UFSCar. Departamento de Química - Brasil
Total Affiliations: 5
Document type: Journal article
Source: Eclética Química; v. 27, p. 61-76, 2002-00-00.
Abstract

Milk analysis can be successfully performed by dilution of samples with CFA-C, a commercial mixture of water-soluble tertiary amines, and measurements by inductively coupled plasma atomic emission spectrometry (ICP-OES). However, due to the costs of this reagent and contamination, the work here described investigated an alternative reagent that could be used instead of CFA-C. Qualitative analysis showed that the commercial mixture does not contain boric acid or EDTA. A potentiometric titration of a CFA-C 10% v/v aqueous solution using HCl as titrant showed two peaks and it was inferred that 90% of the acid was consumed for neutralization of free amines and the remaining 10% was consumed for protonation of an anion of a weak acid employed to generate a buffer R3N/R3NH+ with the molar ratio 10:1. For simulating the CFA-C reagent, it was prepared a solution containing 6.06 mol L-1 monoethanolamine (MEA) plus 0.20 mol L-1 citric acid, triprotic, to form a buffer 10:1. The citrate anion is a good chelating ligand for Ca(II). An other citrate buffer was prepared (1.52 mol L-1) using trishydroxymethylaminomethane (TRIS), which is an amine less soluble in water. These mixtures were characterized by potentiometric and thermal analysis. Both amine/citrate buffers presented a performance comparable to the commercial reagent. (AU)

FAPESP's process: 98/10814-3 - Preparation of agronomic samples and multi-elementary determination by induced plasma atomic emission spectrometry
Grantee:Joaquim de Araújo Nóbrega
Support Opportunities: Research Projects - Thematic Grants