采用电感耦合等离子体质谱法(ICP-MS)测定聚烯烃基和全生物基降解快递袋、降解农膜、降解购物袋、降解餐盒等24批塑料制品中由生产过程中各种添加剂引入的21种特定元素(硼、镁、铝、钛、铬、锰、铁、钴、镍、铜、锌、砷、钼、镉、锶、锡、锑、硒、钡、汞、铅)的含量,并结合相关标准对不同制品中各元素的安全风险水平进行分析。样品经剪碎、冷冻、粉碎后,分取0.3~0.5 g,用硝酸7 mL、30%(质量分数)过氧化氢溶液2 mL在程序升温条件下微波消解。将消解液赶酸至约1 mL,加入硝酸1 mL,用水稀释至50 mL,用0.22 μm滤膜过滤,滤液供ICP-MS分析。结果显示,21种特定元素的质量浓度均在一定范围内与其对应的发射强度呈线性关系,检出限(3S/N)为0.03~0.2 μg·L^-1,加标回收率为94.2%~101%,测定值的相对标准偏差(n=5)为0.47%~9.8%。方法用于实际样品的分析,21种特定元素均有不同程度地检出,汞元素在3类6批、硒元素在4类11批制品中存在超标现象;全生物基制品中的铝、铁、锶、钡含量普遍高于聚烯烃基制品中的;非食品接触类制品(降解快递袋、降解农膜、降解购物袋)中大多数特定元素含量普遍高于食品接触类制品(降解餐盒)中的;钛、镁元素在一些制品中添加量过高,铜、锌、钴、铁、锰、锡、锑、钡等8种元素有一定的迁移风险;相关标准限量要求涵盖的元素不全面,且未区分食品接触类和非食品接触类制品,建议后续修订时予以考虑。

ICP-MS was used to determine the 21 specific elements (boron, magnesium, aluminum, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, molybdenum, cadmium, strontium, tin, antimony, selenium, barium, merary and lead) introduced by various additives in the production process of 24 plastic products, including polyolefin-based and fully bio-based degradable express bags, degradable agricultural films, degradable shopping bags, and degradable lunch boxes. Furthermore, the safety risk level of each element in different products was analyzed according to the relevant standards. The samples were cut into pieces, frozen and pulverized, and an aliquot (0.3-0.5 g) was digested by microwave with 7 mL of nitric acid and 2 mL of 30% (mass fraction) hydrogen peroxide solution under temperature-programmed conditions. After the volume of the digestion solution was concentrated to 1 mL by removing the acid, and 1 mL of nitric acid was added. The solution was diluted to 50 mL with water, and filtered by a 0.22 μm filter membrane, and the filtrate was used to analyze by ICP-MS. It was shown that linear relationships between values of mass concentration and emission intensity of the 21 specific elements were kept in definite ranges, with detection limits (3S/N) of 0.03-0.2 μg·L^-1. Recoveries obtained by addition standard method was in the range of 94.2%-101%, and RSDs (n=5) of the determined values ranged from 0.47% to 9.8% As the proposed method was used for the analysis of actual samples, the 21 specific elements were detected to varying degrees. Detection amounts of mercury element in 6 batches of 3 types and selenium element in 11 batches of 4 types of samples exceeded the limits specified by the relevant standard. The contents of aluminum, iron, strontium and barium in fully bio-based products were generally higher than those in polyolefin-based products; the contents of most specific elements in the non-food contact products (degradable express bags, degradable agricultural films and degradable shopping bags) were generally higher than those in the food contact products (degradable lunch boxes). The detection amounts of titanium and magnesium elements in some products were too high, and the 8 elements (copper, zinc, cobalt, iron, manganese, tin, antimony and barium) had certain migration risks. The elements were not fully covered by limit requirements of relevant standards, and the current standards did not distinguish between the food contact products and non-food contact products. Therefore, it was recommended to consider the above situation in the subsequent revisions.