EXTRACTION AND MICRO-DETERMINATION OF NIOBIUM(V) WITH N-ALPHA-PHENYLSTYRYLACRYLOHYDROXAMIC ACIDS

摘要

A sensitive and selective method for the extraction and microgram determination of niobium(V) with N-p-chlorophenyl-alpha-phenylstyrylacrylohydroxamic acid(PCPPSAHA) is described. The niobium-PCPPSAHA complex has a lambda(max) of 385 nm and a molar absorptivity of 3.7 x 10(4) l mol(-1) cm(-1). The system obeys Beer's law in the range 0.2-4 ppm of niobium(V). The Sandell sensitivity is 0.0025 mu g cm(2). The sensitivity of the method is increased using thiocyanate. The Nb-PCPPSAHA-SCN complex has a lambda(max) of 390 nm and a molar absorptivity 4.7 x 10(4) l mol(-1) cm(-1). Niobium is directly determined by graphite furnace atomic absorption spectrophotometry with detection limit 20 pg. (C) 1996 Academic Press, Inc. [References: 22]