The carbon paste electrodes (CPE) in various degree modified by crosslinked N-2-sulfoehylchitosan with substitution degree of 0.5 are for the first time created. The CPE main electrochemical properties as potentiometric sensors for silver (I) determination (slope, detection limit, linear range of electrode function) are studied. It is shown that all studied CPE in ammonium acetate buffer solution have the super-Nernstian slopes. It is established that ion-selective electrode with a 10 % content of modifier has the lowest detection limit of copper (II) and silver (I), equal 3.2∙10 -7 mol/dm 3 and 6.3∙10 -8 mol/dm 3, respectively. For this sensor a response time and potentiometric selectivity coefficients are defined. Negative logarithms of the selectivity coefficients defined with respect to nickel (II), cobalt (II), lead (II), copper (II), calcium, zinc, strontium, sodium and potassium ions, are equal 4.64, 4.40, 4.38, 4.11, 3.16, 3.06, 4.41, 3.04 and 3.04, respectively. The measurement technique of a silver mass content in solders tin and tin-lead by a potentiometric titration method with use as indicator CPE with the 10 % modifier content is developed. The characteristics of the measurement error are determined, certification is carried out.