Abstract:
Certain agricultural plastics, i.e., mulching films, are generally considered as potent sources of micro- and nanoplastics (MNPs), due to their direct application on soil and waste mishandling. During the synthesis and fabrication of such agricultural plastics, it is necessary to use chemicals, the so-called plastic additives (PAs), improving the physicochemical properties of the final polymeric product. However, since PAs are loosely bound on the polymer matrix, they can potentially leach into the soil environment with unidentified effects. Clearly, to monitor the fate of PAs in the terrestrial ecosystem, it is necessary to develop accurate, sensitive and robust analytical methods. To this end, a comprehensive analytical strategy was developed for monitoring 16 PAs with diverse physicochemical properties (partition coefficient; -3 < logP<19) in soil samples using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). For this purpose, two different extraction procedures were developed, namely, a single step ultrasound-assisted extraction (UAE) using ethyl acetate or an aqueous solution of methanol and a binary extraction, combining Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) and UAE principles with n-hexane as the extractant. Interestingly, within the sample preparation investigation, we identified in-lab contamination sources of PAs, e.g., centrifuge tubes or microfilters. Such consumables are made of plastic contaminating the procedural blanks and omitting their use was necessary to acquire satisfactory analytical performance. In detail, method validation was performed for 16 compounds achieving recoveries mainly in the range 70-120 %, repeatability (expressed as relative standard deviation, RSD %) < 20 % and limits of quantification (LOQs) ranging between 0.2 and 20 ng/g dry weight (dw). Importantly, the presented strategies are added to the very limited available for PA determination in soil, a topical issue with a significant and rather understudied impact on agriculture.
摘要:
某些农用塑料,即,覆盖膜,通常被认为是微米和纳米塑料(MNPs)的有效来源,由于它们直接应用于土壤和废物处理不当。在这种农用塑料的合成和制造过程中,有必要使用化学品,所谓的塑料添加剂(PA),改善最终聚合物产品的物理化学性质。然而,由于PA松散地结合在聚合物基质上,它们可能会渗入土壤环境,并产生未知的影响。显然,监测地球生态系统中PAs的命运,有必要发展准确,灵敏、稳健的分析方法。为此,开发了一种综合分析策略,用于使用超高效液相色谱-串联质谱(UHPLC-MS/MS)监测土壤样品中16种具有不同理化性质(分配系数;-3