Speciation of Fe(II) and Fe(III) by the modified ferrozine method, FIA–spectrophotometry, and flame AAS after cloud-point extraction
Speciation of Fe(II) and Fe(III) by the modified ferrozine method, FIA–spectrophotometry, and flame AAS after cloud-point extraction
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浊点萃取后，采用改进的亚铁嗪法、FIA 分光光度法和火焰原子吸收光谱法对 Fe(II) 和 Fe(III) 进行形态分析
DOI：
10.1007/s00216-002-1326-7
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发表时间：
2002
影响因子：
4.3
通讯作者：
M. Karayannis
中科院分区：
文献类型：
--
作者：
D. Giokas;E. Paleologos;M. Karayannis
建立了一种在线光度法-火焰原子吸收光谱法（FAAS）联用同时测定水中痕量Fe（III）和Fe（II）的方法。该方法涉及在标准条件下用吡咯烷二硫代羧酸铵（APDC）对两种物质进行浊点萃取（CPE），这有助于两种物质的原位络合和萃取。当Fe（III）和Fe（II）存在于同一溶液中时，利用数学方程克服Fe（III）在分光光度法测定Fe（II）中的干扰，实现了铁的氧化态的区分。以这种方式，消除了Fe（II）的预氧化或Fe（III）的还原的耗时且劳动密集的步骤。通过预浓缩10 mL样品溶液，在单步萃取程序后获得低至7 µg L-1的检测限。分光光度法和FAAS法的相对标准偏差（n=4，30 µg L-1）分别为2.6%和1.8%。通过分析加标的真实的样品，回收率在96- 105%范围内。通过分析经认证的参比物质（IMEP-9）进一步验证了该方法;回收率为98.5%。
A method has been developed for the simultaneous determination of traces of Fe(III) and Fe(II) in water by on-line coupling of spectrophotometry with flame atomic absorption spectrometry (FAAS). The method involves cloud-point extraction (CPE) of both species with ammonium pyrrolidinecarbodithioate (APDC) under standard conditions, which facilitates the in situ complexation and extraction of both species. Differentiation of the oxidation states of iron is achieved by using mathematical equations to overcome the interference of Fe(III) in the spectrophotometric determination of Fe(II) when they are both present in the same solution. In this manner the time-consuming and labor-intensive steps of preoxidation of Fe(II) or reduction of Fe(III) are eliminated. By preconcentrating a 10-mL sample solution detection limits as low as 7 µg L–1, were obtained after a single-step extraction procedure. The relative standard deviation (n=4, 30 µg L–1) was 2.6 % and 1.8 % for spectrophotometry and FAAS, respectively. Recoveries in the range of 96–105 % were obtained by analysis of spiked real samples. The method was further verified by analyzing a certified reference material (IMEP-9); for this the recovery was 98.5 %.