抄録
An improved synthetic method for silica-gel immobilized 8-quinolinol is proposed. An aminopropylated silica-gel was reacted with 4-aminobenzoic acid in the presence of 1-ethoxycarbony1-2-ethoxy-1, 2-dihydroquinoline (EEDQ) to synthesize aminobenzamide silica-gel. The product was diazotized with sodium nitrite and coupled with 8-quinolinol by the usual method. EEDQ is easy to handle, since it is stable, less toxic and does not require critical pH control in the synthesis reaction. The synthetic method was simplified and made certain. The adsorbent prepared by using EEDQ was compared with that prepared by a reported method using 4-nitro-benzoyl chloride and sodium dithionite, the other one was synthesized by a Mannich reaction. The silica-gel immobilized 8-quinolinol synthesized by an improved method was applied to the determination of a trace amount of vanadium in river, snow and bottled drinking water samples by ICP-AES after preconcentration. Vanadium (V) and vanadium (IV) were adsorbed quantitatively within the pH range 3.0 to 7.5 and 4.0 to 6.5, respectively. It was possible to determine sub μgl-1 levels of vanadium after a 100-fold preconcentration using synthesized silica-gel immobilized 8-quinolinol.
