Solid phase extraction method for the separation and determination of chromium(III) in the presence of chromium(VI) using silica gel modified by N,N′-bis-(α-methylsalicylidene)-2,2-dimethyl-1,3-propanediimine

► New SPE method for Cr(III) separation/preconcentration was described. ► Silica gel modified with Schiff base was used as adsorbent. ► Conditions for quantitative preconcentration, elution and GFAAS determination were studied. ► The method can be applied to the highly saline samples. ► This method is a simple, effective, accurate and reproducible.