You can estimate carbohydrates by phenol-sulfuric acid method (Dubois et al, 1956) using glucose as standard.
In case of protein estimation, please follow Lowry's method of protein estimation (lowry et al, 1951) using BSA as standard.
Reference: Garcia-Rodriguez, F., Puerto, L. del, Venturini, N., Pita, A. L., Brugnoli, E., Burone, L., & Muniz, P. (2011). Diatoms, protein and carbohydrate sediment content as proxies for coastal eutrophication in Montevideo, Rio de la Plata Estuary, Uruguay. Brazilian Journal of Oceanography, 59(4), 293–310.