Application of microsublimation for sample purification in compound-specific radiocarbon analysis.

Area of Science:

• Analytical Chemistry
• Environmental Science
• Archaeometry

Background:

• Radiocarbon (¹⁴C) analysis requires highly pure samples for accurate dating.
• Contamination from sample handling and purification methods like chromatography can compromise ¹⁴C results.
• Effective isolation of biomarkers is crucial for compound-specific ¹⁴C measurements.

Purpose of the Study:

• To develop and evaluate a microsublimation apparatus for purifying ultra-small samples.
• To reduce contamination introduced during sample preparation for ¹⁴C analysis.
• To enhance the accuracy of compound-specific radiocarbon measurements.

Main Methods:

• Development of a novel, solvent-free microsublimation apparatus constructed from aluminum.
• Application of the apparatus for vacuum sublimation of multiple ultra-small samples.
• Assessment of contamination levels using blank mass and F¹⁴C measurements.
• Evaluation of apparatus efficacy across different compound classes (amino acids, dyes, alkanes).

Main Results:

• The microsublimation apparatus demonstrated minimal carbon contamination (1.35 µg) with a low F¹⁴C value (0.33).
• High purification efficacy was observed for compounds with higher melting points, including amino acids and dyes.
• Lower recovery rates were noted for compounds such as alkanes, indicating limitations for certain sample types.
• The method effectively removes contamination introduced by chromatographic isolation.

Conclusions:

• Microsublimation is a promising technique for enhancing sample purity after chromatography.
• This approach significantly improves the accuracy of compound-specific radiocarbon (¹⁴C) analysis.
• Further optimization is needed to address recovery challenges for specific compound classes like alkanes.