Induced codeposition of the Co-W alloy allows obtaining nanocrystalline coatings which possess high mechanical and corrosive resistance. One of the features of the electrolytes used to obtain CoW coatings is existence of complexes with metals, and the formula of these complexes is usually unknown. Due to this gel-chromatographic method was applied in order to investigate borongluconate electrolyte used for the electrodeposition of Co-W alloy [1].   In the current work an electrolyte with following concentrations (mol/l) was investigated: Na2WO4•– 0,05; CoSO4•– 0,05; С6H11O7Na (sodium gluconate) – 0,04; H3BO3 – 0,65; NaCl – 0,51. Electrolyte separation was performed according to its absorbance in the UV spectra with the wave length of 230 nm. Bio-Gel P-2 was chosen as a sorbent with granule's diameter 40-80 mkm (200400 mesh). Due to different molar mass of the components contained in the electrolyte it was possible to perform separation on this system. To control stability of gel-chromatographic column 0.1 ml of bovine serum albumin (BSA) was as well injected in the column with the electrolyte. Results were obtained and viewed as a graph absorbance-mass (Fig.1). Electrolyte was separated into three fractions (as it is shown on the Fig.1). Investigation of cobalt and tungsten concentrations in fractions shows that first fraction is mostly Co-complex “contaminated” with tungsten. Second and third fractions, opposite, consist of W-complexes “contaminated” with cobalt. Third fraction contained only 3% of cobalt and 15% of tungsten immersed. Cyclic voltammetry (CV) investigations of the obtained fractions were performed with the usage of platinum electrodes in the Ar atmosphere. Potential always started with OCP and was changing in the cathode direction till -1.5V and to the 1.0V later. It was shown that only fractions I and II represent activity at the anodic part of CV. Electrodeposition from fraction III is not observed. Results of EDX analyses of the obtained surfaces by electrodeposition from I and II fractions (E=-0.9V) have demonstrated that deposited metal is mostly Fig.1 Gel-chromatography of the boron-gluconate electrolyte.   Co (>98%) but not Co-W alloy, as it can be deposited from the standard electrolyte. Similar results were obtained if fraction I and II are combined. Nevertheless, if all three fractions are mixed after separation, electrodeposition of alloy Co-W alloy takes place.Obtained results can be explained if Podlaha-Landolt mechanism[2] of alloy deposition is assumed to take place.   This work was supported by the Academy of Sciences of Moldova (project №15.817.02.05.А)