A new methodology for the determination of silicon in plants by wavelength dispersive X‐ray fluorescence

Abstract

Silicon is an important element for plants at their structure and physiology and plays an important role in bone mineralization and soft tissue development in human beings. Furthermore, its determination is being requested more frequently due to nutritional requirements. However, the methods found in the literature to determine silicon in this type of samples require a sample preparation step, which makes them time‐consuming and provides high uncertainties. In this paper, a method for the determination of silicon in plants by wavelength dispersive X‐ray fluorescence (WD‐XRF) spectrometry has been developed. Horsetail (Equisetum arvense L.) and nettle leaf (Urtica dioica) have been used as a source of silicon due to its medical use. Sample preparation involved calcining the sample at 700°C and preparing fused beads from the calcined sample. Calibration standards for WD‐XRF measurement were prepared by mixing certified reference materials and chemical products to reproduce the samples matrix. The linear range for silicon concentration ranges from 6 to 55 wt% SiO2. The validation of the method was performed measuring a reference material (NCS DC73349 Bush branches and leaves) and comparing the results obtained by WD‐XRF with those obtained by an independent method by atomic absorption spectrometry. The developed methodology is rapid and accurate, provides low uncertainties, and is environmentally friendly, as it does require the use of less hazardous reagents.

A review of laboratory, commercially available, and facility based wavelength dispersive X-ray fluorescence spectrometers

“…The energy resolution and spectral intensity were optimized by using a collimator of 300 mm providing an energy resolution of 8 eV measured at the S-K b line with a Ge(111) crystal. An AXIOS Advanced (Malvern Panalytical, The Netherlands) instrument was used by Gazulla et al 46,47 for the determination of silicon in plants and to determine minor and trace elements in liquid petroleum products. This spectrometer was equipped with a 4 kW Rh tube with a maximum current of 160 mA and a variable voltage up to 60 kV, 8 different crystals, up to 6 different collimators and a ow, scintillation and sealed detectors, which have the possibility to operate in a He atmosphere.…”