The theses compares analytical methods according to current norms used in the Czech Republic to the methods based on the principle according to US EPA. A new device the automatic photometer Aquakem 250 makes use of the US EPA methods. Prior to its laboratory use in the Institute of Public Health in the town of Ostrava the photometer had to be validated. For the comparsion of the analytical methods ion chromatographic, isotachophoresis, spectrophotometric,titrimetric methods were used. The validation process, which was documented (in validation protocols), was time consuming and technically challenging. It was confirmed that the new Aquakem 250 analyzer provides result that are verified by methods which are in accordance with norms applicable in the Czech Republic. After a successful completion of validation and obtained accreditation the new automatic analyzer was put into regular operation in the chemically laboratory.