ABSTRACT
We present here a technique for setting up detection limits on any fluorescent microscope in conjunction with the fluorophore Nile Red for microplastic identification. Our method also describes a rigorous morphology-specific identification key for microplastics to reduce subjectivity between researchers. The detection limits were established for nine common polymer types and five natural substrates which could result in false-positive signals when using Nile Red for microplastic identification. This method was then applied to real freshwater samples and identified particles were validated with micro-FTIR or Raman spectroscopy. This approach may reduce subjectivity in microplastic identification and counting and enhances transparency, repeatability and harmonization within microplastic research community.â¢Instructions for calibration of detection limits for microplastics on fluorescence microscope systems describedâ¢Microplastic identification key developed and tested to reduce false positive detectionâ¢Lower subjectivity for microplastic identification obtained using the detection limits & identification key.