
Keywords: بتدریستیل آمونیوم برومید; Graphene; Carbon nanotubes; Solid phase extraction; Chromium speciation; 2-5-Br-PADAP; 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol; AAPTS; 3-(2-aminoethylamino)propyltrimethoxysilane; APDC; ammonium pyrrolidine dithiocarbamate; CNF; carbon nanofiber; CN