Castelvetro Valter, Corti Andrea, La Nasa Jacopo, Modugno Francesca, Ceccarini Alessio, Giannarelli Stefania, Vinciguerra Virginia, Bertoldo Monica
Department of Chemistry and Industrial Chemistry, University of Pisa, 56124 Pisa, Italy.
CISUP-Center for the Integration of Scientific Instruments of the University of Pisa, University of Pisa, 56124 Pisa, Italy.
Polymers (Basel). 2021 Mar 5;13(5):796. doi: 10.3390/polym13050796.
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 , 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.
对海洋底栖沉积物中的微塑料（MPs）进行定量分析，通常采用耗时且精度一般的机械分离和显微镜检测方法。在本文中，我们描述了我们创新的微塑料总量聚合物识别与特异性分析（PISA）的结果，该方法之前已在复杂性较低的沙滩沉积物或要求较低（由于微塑料含量高）的污水处理厂污泥上进行过测试，此次应用于对意大利托斯卡纳大区里窝那市西北沿海一个亚潮带区域的底栖沉积物的分析。样本分别从两个浅海站点采集，一个站点的混合海床以粗碎屑为特征，另一个站点以极细的粉质有机成因沉积物为特征。将沉积物过<2 mm筛后，依次用选择性有机溶剂萃取，通过热解气相色谱 - 质谱联用仪（Pyr - GC/MS）对聚苯乙烯（PS）和聚烯烃（PE和PP）这两类聚合物进行定量分析。能够准确检测出PS在8 - 65 ppm范围内的污染情况。对萃取后的残渣进行酸水解，以使所有天然和合成聚酰胺完全解聚，用荧光团标记水解产物中的所有胺化物种，然后通过反相高效液相色谱（RP - HPLC）分析，根据检测到的相应单体胺6 - 氨基己酸（AHA）和己二胺（HMDA）的量，可对污染的尼龙6和尼龙6,6的单体质量在137 - 1523 ppm范围内进行定量分析。最后，对酸水解后的残渣进行碱水解，然后对纯化后的水解产物进行RP - HPLC分析，根据其共聚单体对苯二甲酸的含量，显示聚对苯二甲酸乙二酯（PET）在12.1 - 2.7 ppm范围内存在污染。
