The powder bed-based 3D printing process called multi-jet fusion from HP is used in various industries for different applications. A polymer powder, the so-called fusing and detailing agents, and an IR source are needed. These novel materials offer some challenges for analytical characterization. High-resolution mass spectrometry in combination with a data base search was used as a tool for comprehensive characterization of the agents, the methanol extract of new polyamide 12 powder, and the methanol extract of a grinded 3D printed part. In addition, thermogravimetric studies were carried out. Besides biocides and substances containing ethoxy units, 2-pyrrolidone and triethylene glycol were identified as organic solvents in the agents. The detailing agent contained 3.7% of 2-pyrrolidone and 11.1% of triethylene glycol. The fusing agent contained 18.7% of 2-pyrrolidone and 8.4% of triethylene glycol. Based on the agents’ different functionalities, the water content of the detailing agent was 18% higher as compared to the fusing agent. In addition, the fusing agent contained a carbon black amount of 5.2%. The methanol extract of new polyamide 12 powder contained remaining monomer and oligomer compounds, as well as the oxidation stabilizer Irganox 1098. In the methanol extract of the grinded 3D printed part the cyclic and linear monomer, oligomers, and oxidation stabilizer were found. Moreover, ingredients of the agents were detected. Residues of 2-pyrrolidone, triethylene glycol, 3-benzisothiazolinone, and substances containing ethoxy units were identified in the methanol extract of the grinded 3D printed part. In contrast, no 2-methyl-4-isothiazolin-3-one was observed.