Rapid Determination of Chromium, Arsenic, Selenium, Cadmium, Antimony, Barium, Mercury and Lead in Toy Plastics by Energy Dispersive X-Ray Fluorescence Spectrometer
LIU Chong-hua, OUYANG Yu, CHEN Guan-qian, PENG Cai-hong, SONG Wu-yuan
Guangzhou Customs District Technology Center, Guangzhou 510623, China
Abstract:As the most important items in the field of toy safety, 8 harmful elements (chromium, arsenic, selenium, cadmium, antimony, barium, mercury and lead) were determined by the wet chemical method of sample preparation and instrumental analysis in current most of standard methods, but the pre-treatment process is complicated, time-consuming and costly. EDXRF has the advantages of simple pre-processing, non-destructive, and high efficiency. It is often used widely for the screening of harmful elements in electronic and electrical products. However, due to the variety of elements and toys materials, the lower limits, and the overlapping interference between target elements, it is difficult to use EDXRF to test accurately 8 certain elements in toys up to now. A new rapid method for measuring the content of eight elements in toy plastics by EDXRF was established. The measurement conditions of target elements, such as analytical line, tube voltage, analytical time and sample thickness, were investigated. According to the characteristics of the target elements, 3 combinations of filter and tube voltage were selected finally. This method can complete the test of 8 elements within 135 s totally for one daily sample. The interference from spectra overlap was corrected by the interference coefficient method. The matrix effect was corrected by experience coefficients method, using rhodium scattered radiation as internal standard simultaneously. Polyethylene (PE) and polyvinyl chloride (PVC) were selected as the standard samples to make the working curve according to the characteristics of the common plastic sample matrix of toys. The calibration curve method was effective. For the target elements, the detection limits of this method were between 0.5 and 37 mg·kg-1. It can meet the screening limits requirements of most of the national standards of safety of toys. The accuracy and precision of the method were evaluated by several materials (PP, PE, ABS, PVC). The relative error (n=6) is within 25%, which indicates that the method has good accuracy. The RSD (n=6) is within 6%, except for some RSDs of individual elements in individual samples within 9%~15%, with good precision. If the test time is extended from the 30 s to 2 min, all RSDs can be reduced to less than 5%. The method can be applied to rapid screening detection of the eight harmful elements in all kinds of toy plastics.
Key words:X-ray fluorescence spectroscopy; Toys; Plastics; Harmful elements
刘崇华,欧阳雨,陈冠潜,彭彩红, 宋武元. EDXRF法快速测定玩具塑料中8种有害元素[J]. 光谱学与光谱分析, 2021, 41(03): 739-744.
LIU Chong-hua, OUYANG Yu, CHEN Guan-qian, PENG Cai-hong, SONG Wu-yuan. Rapid Determination of Chromium, Arsenic, Selenium, Cadmium, Antimony, Barium, Mercury and Lead in Toy Plastics by Energy Dispersive X-Ray Fluorescence Spectrometer. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(03): 739-744.
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