Zetium Polymers edition
This application note demonstrates that the Polymers edition of the Zetium spectrometer using the included ADPOL reference materials, is an effective solution for the analysis of additives in polyethylene.
ADPOL is designed for the calibration of important additive elements in plastics and polyolefinic polymers,like polyethylene and polypropylene. The ADPOL standards were developed in collaboration with DSM Resolve, a polymer R&D laboratory with considerable experience in the development of polymer CRMs and the quantitative analysis of trace elements in plastic products.
This study was performed using the wavelength dispersive optics of the Polymers edition of the Zetium spectrometer. It was configured with a 1 kW Rh anode SST R tube and is a fully integrated system with a X-Y sample handler and state-of-the-art SuperQ software, featuring an advanced Fundamental Parameters algorithm. The Zetium platform is engineered for excellence in terms of both analytical accuracy, precision and operational performance.
Sample preparation and measurement details
Before the measurement, all ADPOL discs were cleaned with de-ionized water and dried with soft laboratory paper. A 10 minute measuring program was used and specific measurement times for each element are presented in Table 1.
Table 1. Measurement times
The accuracies of the calibrations are presented in Table 2. The calibration RMS value is a statistical comparison (1 sigma) of the certified chemical concentration of the CRMs with the concentrations calculated by regression in the calibration procedure.
Table 2. Calibration quality and accuracy
A calibration plot for Ti gives a graphic illustration of the accuracy of the method, Figure 1.
Figure 1. Calibration graph for titanium
Precision and instrument stability
The repeatability and reproducibility of Zetium are very good, not only for short-term measurements, but also for longer periods.
For comparison the counting statistical error (CSE in mg/kg) is also shown in Table 3. The CSE is theoretically the minimum possible error and the data demonstrate the inherent stability of the Zetium instrument.
Table 3. Analytical precision
Note: The repeatability measurements were made on 20 separate ADPOL discs. Repeated measurement of a single ADPOL standard will cause the sample to ‘age’ rapidly and will not reflect the precision of the XRF instrument nor the sample to sample precision that can be expected during routine measurement.
Detection limits typical for elements of interest in polymer matrices are listed in Table 4. The application LLD values are those obtained for measurement times given in Table 1.
Table 4. Detection limits
The Polymers edition of the Zetium spectrometer enables the accurate and repeatable measurement of elements and additives in polymer and plastic products ranging from virgin polymer to recycled plastics. Combined with ADPOL, the Zetium spectrometer is designed to meet the demands of the plastic and polymer industry.