This chapter introduces biodegradable polymer mass spectrometry innovative stochastic dynamics equations for exact structurally determining analytes studying polybutylene adipate terephthalate and polybutylene succinate biopolymers used to packing industry. It aims throughout at making the reader aware of novel methods for quantitative and structural mass spectrometry applicable to reactions of proton transfer and intramolecular rearrangements; cleavages of various bonds and end-group structure types; and linear and cyclic oligomers of biodegradable polymers, which receive tremendous attention on fundamental science, industry, and government policy. The issue is a major challenge for modern society. It connects among environmental plastic pollution, global greenhouse gases emissions, and human health. Established directives define performances and data interpretation of mass spectrometry and infrared spectroscopy in (bio)plastic ecotoxicological and human health risk assessment. There is drawback determining even single analyte (bio)polymers via known routine methods. The analysis is frequently manual. The novel equations bypass mass spectrometric drawback of structural analysis of petroleum-based biodegradable plastic bars, food tray, and waste bags. Mass spectrometry, quantum chemistry, infrared spectroscopy, and chemometrics are used. The achieved excellent performances of |r| = 0.99904 of [PLA-b-PBAT] using seven analyte characteristic ions are pro-arguments favoring the applicability of the formulas as reliable tools to mass spectrometric-based structural analysis.