Study of nitrophenols preconcentration using quinolin-8-ol immobilized on controlled-pore glass in the presence of iron(III) -: Chromatographic determination of dinoseb in lemon juice

The efficiency of an adsorbent consisting of quinolin-8-ol immobilized on controlled-pore glass which was packed in a minicolumn to preconcentrate nitrophenols in the presence of iron(III) has been established. Retention was carried out at acidic pH in the presence of 20 mM iron(III). Methanol-30 mM formic acid-sodium formate aqueous solution (pH 4.2) (65:35) was used in a one-step elution. Determinations were carried out by using liquid chromatography with detection at 350 nm. Determination of trace amounts of dinoseb in lemon juice was carried out with a minimum sample preparation. Recoveries were between 89 and 100% at 200-33 mu g l(-1). The maximum admissible concentration in fruit juice dictated by the Spanish and European Community legislation can be measured. (C) 1999 Elsevier Science B.V. All rights reserved.