In this chapter, a general discussion regarding the analysis of pesticides, and free radicals is included, although details about the methods for their analysis are not provided. Pesticides and free radicals are not listed as HPHCs by the FDA, but they are toxicants and methods for their analysis are reported in the literature which is referenced in this chapter. In addition, a short discussion about the non-targeted type of analysis is included. A critical view of the advantages and challenges in the application of this type of analysis for toxicants is presented.