Currently, a reliable and efficient extraction method is needed to quantify traces of microplastic (MP) particles from different sources within soil matrices. Most studies surrounding MP research are focused on the marine environment and only a few studying MP in soil, which consist of varying approaches, methods, and are more difficult to extract and compare. A new method for quantitative detection of MP in soil is being developed combining offline pyrolysis with TD-GC-MS based on Dümichen et al. (2017). We tested pure plastics (PE, PET, PS) and plastics in sample matrices of increasing complexity, finishing with soil. Then, samples were pyrolyzed in an oven and products are adsorbed to a sorbent which is then put through a thermal desorption unit and the degradation products analyzed. A novel approach using tandem MS/MS is used to further separate, identify, and quantify a mixture of various microplastic types. Pyrolysis extraction variables were evaluated, such as N2 flow rate, temperature ramp, linearity of MP concentration vs pyrolysis products, and optimizing TD-GC-MS/MS settings for repeatable detection and quantification. Matrices containing organic matter will be treated according to Möller et al. (2020) to reduce noise of soil to plastic contents. This method is approaching a final challenge to lower current detection limits for MP in soil and be ready to evaluate microplastic concentration in soil and rhizosphere down to 1 mg kg-1.