Department of Analytical Chemistry, Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw, Poland.
Talanta. 2003 Jul 4;60(4):643-52. doi: 10.1016/S0039-9140(03)00041-9.
Solid-phase extraction (SPE) along with reversed-phase liquid chromatography (RP-LC) was used for the simultaneous determination of Zr(IV) and Hf(IV) by means of their ternary chelates with fluoride and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP). The conditions of SPE sorption were examined in detail: type of SPE column, volume of the sample, volume of the eluent, concentrations of metal ions, fluoride salt, chromogenic reagent, organic phase, and pH. It was established that the sorption of Zr(IV) and Hf(IV), as their ternary chelates, on SPE Zorbax SPE C18 (EC) cartridge was the most efficient, when the sample containing metal ion (Zr(IV), Hf(IV), both, up to 2 mug), 5-Br-PADAP 1.5x10(-4), NaF 7.5x10(-5) mol l(-1), methanol 40%, pH 4.5+/-1 was applied for the SPE sorption. The chelates were discarded from SPE cartridge using acetonitrile/water (99.75+0.25, v/v) eluent containing 3.8x10(-4) mol l(-1) sodium fluoride and subsequently separated by RP-LC method. The RP-LC separation of both chelates was optimized and Zorbax SB-C18 analytical LC column along with acetonitrile/water (65+35, v/v) eluent containing the 1.5x10(-4) mol l(-1) sodium fluoride was used. The established SPE/LC conditions allow Zr(IV) 0.08-2.0 mug and Hf(IV) 0.04-2.0 mug determination in a sample volume up to 150 ml. The detection limits, 0.03 mug Hf(IV) and 0.05 mug Zr(IV), were obtained. Recoveries, (94+/-2)% for Hf(IV) chelate and (106+/-2)% for Zr(IV) chelate were obtained, when 1 mug of Zr(IV) and Hf(IV) ions were determined by the present SPE/LC method from the sample volume of 100 ml. The established, pre-concentration SPE conditions, along with the LC separation and determination allow the assay of Zr(IV) and Hf(IV) in complicated matrix materials. The present SPE/LC method was applied to the determination of Zr(IV) and Hf(IV) in tap water and reference geological material (rock, NCS DC 73303; certified content: Zr, 27.7x10(-3)% (w/w) and Hf, 6.5x10(-4)% (w/w)).
固相萃取 (SPE) 与反相液相色谱 (RP-LC) 联用，通过氟化物和 2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚 (5-Br-PADAP) 与 Zr(IV) 和 Hf(IV) 的三元螯合物同时测定它们。详细考察了 SPE 吸附的条件：SPE 柱的类型、样品体积、洗脱液体积、金属离子、氟盐、显色剂、有机相和 pH 值的浓度。结果表明，当样品中含有金属离子 (Zr(IV)、Hf(IV)，最高达 2μg)、5-Br-PADAP 1.5x10(-4)、NaF 7.5x10(-5)mol l(-1)、甲醇 40%、pH 4.5+/-1 时，Zr(IV)和 Hf(IV)作为其三元螯合物在 SPE Zorbax SPE C18 (EC) 柱上的吸附最为有效。用含 3.8x10(-4)mol l(-1)氟化钠的乙腈/水 (99.75+0.25，v/v) 洗脱液从 SPE 柱上洗脱螯合物，然后用 RP-LC 法分离。优化了两种螯合物的 RP-LC 分离条件，采用 Zorbax SB-C18 分析型 LC 柱和含 1.5x10(-4)mol l(-1)氟化钠的乙腈/水 (65+35，v/v) 洗脱液。建立的 SPE/LC 条件允许在样品体积高达 150ml 时测定 0.08-2.0μg 的 Zr(IV)和 0.04-2.0μg 的 Hf(IV)。检测限为 0.03μg Hf(IV)和 0.05μg Zr(IV)。当通过本 SPE/LC 方法从 100ml 样品中测定 1μg 的 Zr(IV)和 Hf(IV)离子时，得到了 Hf(IV)螯合物的回收率 (94+/-2)% 和 Zr(IV)螯合物的回收率 (106+/-2)%。建立的预浓缩 SPE 条件与 LC 分离和测定相结合，允许在复杂基质材料中测定 Zr(IV)和 Hf(IV)。本 SPE/LC 方法已应用于自来水中 Zr(IV)和 Hf(IV)的测定以及参考地质材料 (岩石，NCS DC 73303; 认证含量：Zr，27.7x10(-3)%(w/w)和 Hf，6.5x10(-4)%(w/w))。
