The European Union announced drastic measures to increase the recycling quote of plastic waste as part of the recently announced Green Deal. The member countries of the European Union produce approximately 26 million tons of plastic waster per year and currently only 32,5% of the incidental waste is being recycled in sharp contrast to the target of a 55% recycling quota in 2030. One of the many reasons for the currently low recycling quota is the challenge of plastic recycling processes to continuously ensure the needed output quality of secondary plastic as a input flow for industrial purposes. One key for solving the ambitious target for plastic recycling is to improve the quality of waste flow analysis and monitoring. Finding better and more reliable methods to ensure the needed proportions of certain value element inside of the waste fraction is key to ensure the needed high quality for the recycling output products. This thesis was conducted as part of the wider CD-labor initiative. An initiative focused on increasing understanding of efficient, recycling-based Circular Economy. Focus of this thesis was the comparison of different measurement methods in the near-infrared range to determine the polyolefin content of plastic waste fractions. This has special relevance to chemical recycling, an approach needed to recycle older, currently not-recyclable plastic waste fractions. High-caloric plastic waste samples from mixed industrial and municipal waste were presorted bevor being divided in two sample groups, washed, and labeled. The samples, washed and unwashed, are then examined using three different infrared spectroscopy analysis methods (FTIR, NIR-Handheld, NIR-Sorter) to determine the PO-content of the sample. The resulting data set is then analyzed statistically, and the results and challenges are interpreted for further usage in upcoming research and industry projects. The Polyolefin recovery rate of the NIR-Handheld (97.1% for unwashed and 96.7% for washed samples) is lower than of the NIR-sorter (99.1% for unwashed and 101.4% for washed samples), however, the purity is significantly higher.