Evaluation of X-ray Fluorescence Spectroscopy as a Tool for Element Analysis in Pea Seeds
Date
2019-01-28
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-1502-4676
Type
Thesis
Degree Level
Masters
Abstract
X-ray fluorescence spectroscopy (XRF) is a powerful analytical tool for the determination of elemental composition of diverse materials. The principal aim of this study was to evaluate and characterize the utility and reliability of synchrotron-based XRF for use in element analysis of field pea seeds for quantification of macro- (K and Ca) and micro- (Mn, Fe, Cu, Zn, Se) elements. Pea seed samples were ground into fine flour and pellets were prepared to collect XRF peak intensities. Seventy-three pea seed samples were selected to cover the expected concentration ranges for each element for developing calibration curves by correlating the results from atomic absorption spectroscopy (AAS) reference method and XRF peak intensities. For all the calibration curves R2 values were above 0.8 except for K (0.5). XRF results were validated by a systematic comparison with data obtained from AAS on a set of 80 additional and independent pea seed samples (Validation Set). Element concentrations were also predicted using the fundamental parameter approach collectively for 153 samples. Limit of detection was calculated as low as 0.016 mg/kg for Se and 9.54 mg/kg for K. For Mn, Cu, Zn, Se, the XRF method was found to be not statistically different from AAS method at 95% confidence interval; furthermore, the bias between the methods was not significantly different from 0. Relative standard deviation (RSD) was less than 26% in XRF and range of recovery 75-165% for different elements. For the lower energy elements K and Ca, significant negative bias was observed (statistically different from 0) indicating underprediction by XRF method. The intercepts of the validation curve were -1460.3 and -61.27 for K and Ca respectively. Similar results were obtained with the fundamental parameter approach except for Fe for which significant bias of ~6 mg/kg was calculated. The intercept of validation curves was found to be not significantly different from 0 and B (the slope) was found to be not significantly different from 1. This leads to the conclusion that the results obtained using XRF and AAS were statistically not different from AAS method at 95% confidence interval. This study demonstrated that the XRF technique is a fast and reliable tool for element analysis, particularly for high energy elements and does not produce waste and requires no chemical reagents.
Description
Keywords
X-ray Fluorescence Spectroscopy, Element, Peas, Atomic Absorption Spectroscopy
Citation
Degree
Master of Science (M.Sc.)
Department
Plant Sciences
Program
Plant Sciences