Nowadays, carbon nanotubes with differences in specific surface area, dopants, or functional groups are used in a number of applications, electrolysis not excluding. Various types of carbon nanotubes could improve bare graphite electrode properties by different way and so result in obtaining the different records for the same analyte. The automobile catalysts represent mobile sources of palladium. Levels of palladium in environment are continuously increasing and they need to be monitored. Electrochemistry is a useful and inexpensive component of the field of environment monitoring. For Pd(II) electrochemical determination, six types of carbon nanotubes were used as paraffin impregnated graphite electrode (PIGE) surface modifiers. Voltammetric determination brought interesting results of LOD, LOQ, standard and relative precisions of the method. These parameters as well as prediction intervals were calculated according to the technical procedure DIN 32 645 for the six electrodes and three pH values. Modification of PIGE with nitrogen doped carbon nanotubes (LOD = 1.91 x 10(-5) mol L-1 or 3.14 x 10(-5) mol L-1 for pH 3 and pH 4.5, respectively) seems very promising. In laboratory, functionalized carbon nanotubes, with specific surface area 200 m(2) g(-1), provided LOD = 1.49 x 10(-5) mol L-1 (pH = 3) and 1.42 x 10(-5) mol L-1 (pH = 4.5)