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Leaching of trace elements from biological tissue by formalin fixation
Kristin Gellein1, Trond Peder Flaten, Keith M Erikson
1Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway.
Biological Trace Element Research
|October 24, 2007
Summary
Formalin fixation leaches significant trace elements from biological tissues, impacting analysis. Element leaching varies by type and storage duration, necessitating careful consideration for formalin-fixed samples.
Area of Science:
- Biogeochemistry
- Analytical Chemistry
- Histology
Background:
- Trace element analysis in biological tissues is crucial for research.
- Formalin fixation is common but may alter elemental composition.
- Limited studies exist on formalin's effect on trace elements in tissue.
Purpose of the Study:
- To quantify trace element leaching from formalin-fixed human and rat brain tissue.
- To assess the impact of storage duration on element leaching.
- To determine which elements are most affected by formalin fixation.
Main Methods:
- High-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) was used.
- Analyzed trace element concentrations in formalin storage solutions.
- Analyzed trace element concentrations in formalin-fixed brain tissue samples.
Main Results:
- Substantial leaching of 19 trace elements into formalin was observed.
- Leaching varied significantly between elements; As, Cd, Mg, Rb, Sb showed >100-fold increase.
- Leaching was strongly time-dependent, with negligible loss for Ni and Cr.
- Significant element loss occurred over years of storage.
Conclusions:
- Formalin fixation and storage can lead to substantial loss of several trace elements from biological tissues.
- The extent of leaching is element-specific and time-dependent.
- Researchers must critically evaluate potential leaching when using formalin-fixed tissues for trace element analysis.
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