... Preconcentration of element anions on the filters with bound quaternary amino groups . ... Conditions for preconcentration of vanadium, arsenic and chromium from 250 ml of aqueous solutions (preconcentration coefficient was 5 10 3 ) were found. ... Moscow University Chemistry Bulletin . 2008, Vol. ... 6, P. 403 . Copyright (C) Chemistry Dept., Moscow State University, 2002 . ... Copyright (C) Chemisty Department of Moscow State University . ... Web-design: Copyright (C) MIG and VVM . ...