Quantifying Trace Elements in Individual Aquatic Protist Cells with a Synchrotron X-ray Fluorescence Microprobe
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- 作者：Benjamin S. Twining ; Stephen B. Baines ; Nicholas S. Fisher ; Jö ; rg Maser ; Stefan Vogt ; Chris Jacobsen ; Antonio Tovar-Sanchez ; and Sergio A. Sañ ; udo-Wilhelmy
- 刊名：Analytical Chemistry
- 出版年：2003
- 出版时间：August 1, 2003
- 年：2003
- 卷：75
- 期：15
- 页码：3806 - 3816
- 全文大小：332K
- 年卷期：v.75,no.15(August 1, 2003)
- ISSN：1520-6882
文摘
The study of trace metal cycling by aquatic protists islimited by current analytical techniques. Standard "bulk"element analysis techniques that rely on physical separations to concentrate cells for analysis cannot separate cellsfrom co-occurring detrital material or other cells of differing taxonomy or trophic function. Here we demonstratethe ability of a synchrotron-based X-ray fluorescence(SXRF) microprobe to quantify the elements Si, Mn, Fe,Ni, and Zn in individual aquatic protist cells. This technique distinguishes between different types of cells in anassemblage and between cells and other particulate matter. Under typical operating conditions, the minimumdetection limits are 7.0 × 10-16 mol 
m-2 for Si andbetween 5.0 × 10-20 and 3.9 × 10-19 mol m-2 for Mn,Fe, Ni, and Zn; this sensitivity is sufficient to detect theseelements in cells from even the most pristine waters asdemonstrated in phytoplankton cells collected from remote areas of the Southern Ocean. Replicate analyses ofsingle cells produced variations of <5% for Si, Mn, Fe,and Zn and <10% for Ni. Comparative analyses ofcultured phytoplankton cells generally show no significantdifferences in cellular metal concentrations measuredwith SXRF and standard bulk techniques (spectrophotometry and graphite furnace atomic absorption spectrometry). SXRF also produces two-dimensional maps ofelement distributions in cells, thereby providing information not available with other analytical approaches. Thistechnique enables the accurate and precise measurementof trace metals in individual aquatic protists collected fromnatural environments.
m-2 for Si andbetween 5.0 × 10-20 and 3.9 × 10-19 mol m-2 for Mn,Fe, Ni, and Zn; this sensitivity is sufficient to detect theseelements in cells from even the most pristine waters asdemonstrated in phytoplankton cells collected from remote areas of the Southern Ocean. Replicate analyses ofsingle cells produced variations of <5% for Si, Mn, Fe,and Zn and <10% for Ni. Comparative analyses ofcultured phytoplankton cells generally show no significantdifferences in cellular metal concentrations measuredwith SXRF and standard bulk techniques (spectrophotometry and graphite furnace atomic absorption spectrometry). SXRF also produces two-dimensional maps ofelement distributions in cells, thereby providing information not available with other analytical approaches. Thistechnique enables the accurate and precise measurementof trace metals in individual aquatic protists collected fromnatural environments.