微塑料(MPs)在各种环境中的普遍存在越来越受到关注。尽管微傅里叶变换红外光谱(μ-FTIR)是一种理想的检测方法,这种技术缺乏在不同环境矩阵中MP遵循的标准化模式。本研究侧重于优化,应用程序,并验证μ-FTIR技术用于识别较小尺寸的MP(20μm-1mm)。为了评估μ-FTIR(反射和透射)中各种检测模式的有效性,用已知的标准聚合物进行验证试验,viz.,聚乙烯(PE),聚丙烯(PP),聚苯乙烯(PS),聚酰胺(PA),和聚氯乙烯(PVC)执行。随后,对于方法的验证和准确性,将在μ-FTIR(较小尺寸)中获得的标准聚合物的聚合物光谱与在FTIR-ATR(衰减全反射)中的较大尺寸颗粒(相同标准)的光谱进行比较。光谱是可比较的并且突出了聚合物组合物的类似图案。将参考文库的光谱质量和匹配分数(>60%)考虑在内以强调不同方法的真实性。这项研究强调了反射模式(尤其是漫反射)对于定量复杂环境样品中的较小尺寸MP更有效。同样的方法被成功地应用于一个有代表性的环境样品(沙子),由EURO-QCHARM实验室间研究提供。两种聚合物(PE和PET)从三种掺加聚合物(PE,给定样品中的PET和PS)。同样,在匹配算法方面,与微ATR(PE-67%和PET-63.2%)反射模式相比,漫反射(PE-71.7%和PET-89.1%)的结果令人满意。总的来说,这项研究说明了不同μ-FTIR技术的广泛前景,推荐最可靠的,容易和非破坏性的方法来明确地表征不同类型的聚合物的较小的MPs在复杂的环境基质。
The ubiquity of microplastics (MPs) in the various environment is of increasing concern. Although micro Fourier Transform Infrared Spectroscopy (μ-FTIR) represents an ideal method for the detection of MPs, this technique lacks a standardized mode to be followed for MPs in diverse environmental matrices. The study focused on the optimization, application, and validation of μ-FTIR techniques for the identification of smaller-sized MPs (20 μm-1 mm). In order to assess the validity of the various detection modes in μ-FTIR (reflection and transmission), a confirmatory test with known standard polymers, viz., polyethylene (PE), polypropylene (PP), polystyrene (PS), polyamide (PA), and polyvinyl chloride (PVC) were executed. Subsequently, for the validation and accuracy of the method, the polymer spectra of standard polymers acquired in μ-FTIR (smaller-sized) were compared with spectra of larger-sized particles (same standards) in FTIR-ATR (Attenuated Total Reflectance). The spectra were comparable and highlighted the similar pattern of the polymeric composition. The spectral quality and matching score (>60 %) with the reference library was taken into account to accentuate the authenticity of the different methods. This study highlighted the reflection mode (particularly diffuse reflection) as more effective for the quantification of smaller-sized MPs in complex environmental samples. The same method was successfully applied to a representative environmental sample (sand), supplied by the EURO-QCHARM for inter-laboratory study. Two polymers (PE and PET) were correctly identified out of three spiked polymers (PE, PET, and PS) in the given sample. Similarly, in terms of matching algorithms, the results for diffuse reflection (PE-71.7 % and PET-89.1 %) were found satisfactory as compared to micro-ATR (PE-67 % and PET-63.2 %) reflection mode. Overall, this study illustrates an extensive perspective of different μ-FTIR techniques, recommending the most reliable, easy, and non-destructive method to unambiguously characterize diverse types of polymers of smaller MPs in complex environmental matrices.