Analysis and storage of samples for chromium determination in seawater
Analysis and storage of samples for chromium determination in seawater
复制标题
海水中铬测定样品的分析和储存
DOI：
10.1016/s0003-2670(97)00512-6
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
S. Westerlund
中科院分区：
文献类型：
--
作者：
W. Sirinawin;S. Westerlund
研究了海水中铬的测定方法。该方法基于用三辛基甲基氯化铵（Aliquat-336）将Cr（VI）离子对萃取至甲基异丁基酮（MIBK）中。采用石墨炉原子吸收分光光度法（GFAAS）分析浸提液。还显示了通过Cr（III）的氧化来测定总铬的可能性。为了避免形态变化，还研究了天然海水样品的不同储存方法。在自然pH值和室温下，沿海海水可储存至少一个月。在冰冻的海水中，Cr（VI）至少在8个月内是稳定的。该方法可以快速测定Cr（VI）。在卡斯-2参考物质上的测量给出Cr（VI）浓度为2.76±0.09nM（n=6），而认证值为2.32±0.40nM。基于空白3σ的检测限为0.1 nM。总铬的测定更耗时，精度略低。
An improved method for determination of chromium in seawater has been developed. The procedure is based on the ion-pair extraction of Cr(VI) with tricaprylmethyl ammonium chloride (Aliquat-336) into methyl isobutyl ketone (MIBK). The extract is analyzed by Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS). The possibility to determine total chromium by oxidation of Cr(III) is also shown. Different ways for storage of natural seawater samples in order to avoid speciation changes were also investigated. Coastal seawater could be stored at least one month at natural pH and at room temperature. Cr(VI) in frozen oceanic water is stable for at least eight months. The method allows rapid determination of Cr(VI). Measurements on CASS-2 reference material gave a Cr(VI) concentration of 2.76±0.09nM (n=6), compared to the certificated value 2.32±0.40nM. The detection limit based on 3σ of the blank is 0.1nM. The determination of total chromium is more time-consuming and has a slightly lower precision.