Use of the Relaxometry Technique for Quantification of Paramagnetic Ions in Aqueous Solutions and a Comparison with Other Analytical Methods.
We have demonstrated that the relaxometry technique is very efficient to quantify paramagnetic ions during in situ electrolysis measurements. Therefore, the goal of this work was to validate the relaxometry technique in the determination of the concentration of the ions contained in electrolytic solutions, Cu(2+), Ni(2+), Cr(3+), and Mn(2+), and compare it with other analytical methods. Two different NMR spectrometers were used: a commercial spectrometer with a homogeneous magnetic field and a home-built unilateral sensor with an inhomogeneous magnetic field. Without pretreatment, manganese ions do not have absorption bands in the UV-Visible region, but it is possible to quantify them using relaxometry (the limit of quantification is close to 10(-5) mol L(-1)). Therefore, since the technique does not require chemical indicators and is a cheap and robust method, it can be used as a replacement for some conventional quantification techniques. The relaxometry technique could be applied to evaluate the corrosion of metallic surfaces.
Instituto de Química de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-Carlense 400, 13560-070 São Carlos, SP, Brazil.
Bruna Ferreira
0000-0002-6879-3583
BF
Gomes
Instituto de Química de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-Carlense 400, 13560-070 São Carlos, SP, Brazil.
Juliana Soares da Silva
JS
Burato
Instituto de Química de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-Carlense 400, 13560-070 São Carlos, SP, Brazil.
Carlos Manuel
CM
Silva Lobo
Embrapa Instrumentação, Rua XV de Novembro 1452, 13560-970 São Carlos, SP, Brazil.
Luiz Alberto
LA
Colnago