Pesticides considered to be synthetic or natural substances are used to control pests or unwanted harmful organisms and are very common in the environment. Pesticides are at the same time a direct threat to the health of living humans. According to the Stockholm Convention on Persistent Organic Pollutants, nine of the 12 most dangerous and persistent organic chemicals are pesticides. Due to the diversity of chemical structures (even only between organochlorines, organophosphorus, and carbamate pesticides) continuous monitoring and identification, along with residue analysis, of pesticides is important.