Analyzing Pollen by Infrared and Raman Spectroscopy.

Mid-infrared (mid-IR) and Raman vibrational spectroscopy have been widely adopted in pollen research due to their unique capability for simultaneous taxonomic identification and comprehensive chemical profiling in a single measurement. The integration of both bulk (macro-sampling) and microscopy-based spectroscopic techniques provides complementary insights, where bulk measurements enable efficient, high-throughput screening of pollen samples, whereas microspectroscopies enable detailed analysis of single-grain heterogeneity and substructural chemical composition. Here, we present one Raman and three mid-IR methods for bulk pollen measurements, as well as one Raman and one mid-IR microspectroscopy method. Additionally, we provide guidelines for the preprocessing of spectral data, including advanced spectral preprocessing approaches related to Mie-type scattering interferences in mid-IR microspectroscopy.