底栖海洋沉积物中的微塑料(MP)定量通常通过耗时且中等精确的机械分离和显微镜检测来进行。在本文中,我们描述了我们创新的聚合物鉴定和特殊分析(PISA)的结果,先前在较不复杂的沙滩沉积物或要求较低(由于高MP含量)的废水处理厂污泥上进行了测试,应用于分析来格霍恩西北部沿海区域的底栖沉积物(托斯卡纳,意大利)。样本是从海洋波西多尼亚混合海床的两个浅层地点收集的,这些浅层地点的特征是粗碎屑,和一个非常细的粉质有机沉积物,分别。在<2mm下筛分后,用选择性有机溶剂萃取沉积物,并通过热解-气相色谱-质谱(Pyr-GC/MS)定量两种聚合物类别聚苯乙烯(PS)和聚烯烃(PE和PP)。可以准确地检测到PS在8-65ppm范围内的污染。对提取的残留物进行酸水解,以实现所有天然和合成聚酰胺的完全解聚,用荧光团标记水解产物中的所有胺化物种,和反相高效液相色谱(HPLC)(RP-HPLC)分析,基于检测到的相应单体胺6-氨基己酸(AHA)和六亚甲基二胺(HMDA)的量,允许在污染尼龙6和尼龙6,6的单个质量的137-1523ppm范围内进行定量。最后,酸水解残留物的碱水解,然后对纯化的水解产物进行RP-HPLC分析,显示聚对苯二甲酸乙二醇酯(PET)的污染在12.1-2.7ppm范围内,根据其共聚单体的含量,对苯二甲酸。
Microplastics (MPs) quantification in benthic marine sediments is typically performed by time-consuming and moderately accurate mechanical separation and microscopy detection. In this paper, we describe the results of our innovative Polymer Identification and Specific Analysis (PISA) of microplastic total mass, previously tested on either less complex sandy beach sediment or less demanding (because of the high MPs content) wastewater treatment plant sludges, applied to the analysis of benthic sediments from a sublittoral area north-west of Leghorn (Tuscany, Italy). Samples were collected from two shallow sites characterized by coarse debris in a mixed seabed of Posidonia oceanica, and by a very fine silty-organogenic sediment, respectively. After sieving at <2 mm the sediment was sequentially extracted with selective organic solvents and the two polymer classes polystyrene (PS) and polyolefins (PE and PP) were quantified by pyrolysis-gas chromatography-mass spectrometry (Pyr-GC/MS). A contamination in the 8-65 ppm range by PS could be accurately detected. Acid hydrolysis on the extracted residue to achieve total depolymerization of all natural and synthetic polyamides, tagging of all aminated species in the hydrolysate with a fluorophore, and reversed-phase high performance liquid chromatography (HPLC) (RP-HPLC) analysis, allowed the quantification within the 137-1523 ppm range of the individual mass of contaminating nylon 6 and nylon 6,6, based on the detected amounts of the respective monomeric amines 6-aminohexanoic acid (AHA) and hexamethylenediamine (HMDA). Finally, alkaline hydrolysis of the residue from acid hydrolysis followed by RP-HPLC analysis of the purified hydrolysate showed contamination by polyethylene terephthalate (PET) in the 12.1-2.7 ppm range, based on the content of its comonomer, terephthalic acid.