Kagaya S, Saiki M, Malek Z A, Araki Y, Hasegawa K
Department of Chemical and Biochemical Engineering, Faculty of Engineering, Toyama University, Gofuku, Japan.
Fresenius J Anal Chem. 2001 Oct;371(3):391-3. doi: 10.1007/s002160100976.
The usefulness of coprecipitation with lanthanum phosphate for separation and preconcentration of some heavy metals has been investigated. Although lanthanum phosphate coprecipitates iron(III) and lead quantitatively at pH 2.3, iron(II) can barely be collected at this pH. This coprecipitation technique was applicable to the separation and preconcentration of iron(III) before inductively coupled plasma atomic-emission spectrometric (ICP-AES) determination; the recoveries of iron(III) and iron(II) from spiked water samples were 103-105% and 0.2-0.7%, respectively. The coprecipitation was also useful for separation of 20 microg lead from 100 mL of an aqueous solution that also contained 1-100 mg iron. Coprecipitation of iron was substantially suppressed by addition of ascorbic acid, which enabled recovery of 97-103% of lead added to the solution, bringing the recovery to within 1.6-5.0% of the relative standard deviations. Lanthanum phosphate can also coprecipitate cadmium and indium quantitatively, although chromium(III), cobalt, and nickel and large amounts of sodium, potassium, magnesium, and calcium are barely coprecipitated at pH approximately/= 3.
研究了用磷酸镧共沉淀法分离和预富集某些重金属的实用性。虽然磷酸镧在pH 2.3时能定量共沉淀铁（III）和铅，但在此pH下几乎不能收集到铁（II）。这种共沉淀技术适用于在电感耦合等离子体原子发射光谱法（ICP-AES）测定之前分离和预富集铁（III）；加标水样中铁（III）和铁（II）的回收率分别为103-105%和0.2-0.7%。共沉淀法也可用于从100 mL还含有1-100 mg铁的水溶液中分离20 μg铅。加入抗坏血酸可显著抑制铁的共沉淀，从而使溶液中添加铅的回收率达到97-103%，相对标准偏差在1.6-5.0%以内。磷酸镧也能定量共沉淀镉和铟，不过在pH约为3时，铬（III）、钴、镍以及大量的钠、钾、镁和钙几乎不发生共沉淀。
