Aplicação da calibração multi-isotópica para determinações multielementares em sangue total por ICP-MS
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Data
2022-12-14
Autores
Oliveira, Poliana Borges de
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Universidade Federal do Espírito Santo
Resumo
The multielement determination in samples of biological fluids is essential in several areas of research. Therefore, it is essential to develop ever more efficient techniques, strategies and methods to simplify, accelerate and make the process of analyzing these samples less expensive. One technique that stands out for this purpose is inductively coupled plasma mass spectrometry (ICP-MS), which has the main characteristics of being highly sensitive and capable of multielement and isotope analysis. However, ICP-MS has some limitations caused by matrix, transport and spectral interferences that are very present when analyzing biological samples, since they are complex matrices. Thus, it is necessary to use strategies aimed at correcting these interferences, such as the use of reaction/collision cells and appropriate calibration methods. This study proposes the use of multi-isotopic calibration (MICal) in the determination of Cd, Cr, Hg, Mo, Ni, Pb, Se, Sn and Zn in whole blood and compares the performance of MICal with the already traditional, external calibration ( EC), internal standardization (IS), matrix matching calibration (MMC) and standard addition calibration (SA). MICal consists of the simultaneous monitoring of several isotopes of the elements of interest in only two solutions, both containing the same amount of sample. The calibration solutions used in MICal were prepared in the proportion of 5% vv¹ of sample and 95% vv-¹ of standard or blank, in order to provide greater dilution for the matrix. The concentration of the standard to be added for each analyte was optimized for MICal, from these concentrations the constructed calibration curves were evaluated, identifying possible discrepant points. In the evaluation of the graphic representations, the isotopes of each element that presented outliers were verified due to the presence of polyatomic and isobaric interferences, being possible to remove these signals, which improved the linearity of the curves and the coefficient of determination. Accuracy, precision and limits of detection and quantification were also determined for MICal and compared with the other calibrations. For most of the analytes, the concentrations found in MICal showed significant differences compared to those obtained by EC and IS, however, they were equivalent to the concentrations determined by MMC and SA, at a confidence level of 95%. In calibrations using matrix, the results obtained were better in terms of recovery, calculated from the concentration of the control material in whole blood. MICal presented recoveries in a range of 67.97-108.86% for the analytes studied, standing out as a good alternative for the determination of trace elements in whole blood. The LOD's and LOQ's for MICal were compared with those for MMC and SA also showed similar concentrations. These results confirm that MICal is a viable strategy for determining the studied elements present in whole blood, providing advantages over other techniques due to its time and material savings, less waste generation and identification of interferences.
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Sangue total , Calibração , MICal , Multielementar , ICP-MS