# Isolation of Underivatized Amino Acids for Radiocarbon Analysis Using a Porous Graphite Column

## TL;DR

A new method isolates amino acids for precise radiocarbon analysis using a graphite column, enabling accurate measurements from very small samples.

## Contribution

A single-step method using a porous graphite column enables reliable isolation of underivatized amino acids for radiocarbon analysis.

## Key findings

- The method successfully separates and isolates all proteinogenic amino acids in one step.
- Radiocarbon measurements using this method show minimal contamination and high reliability.
- The blank contribution was calculated as 1.0 ± 0.3 μg C with F14C = 0.6 ± 0.12.

## Abstract

We developed a method for isolation and purification
of individual
underivatized amino acids for compound-specific radiocarbon analysis.
Our method employs a semipreparative porous graphitic carbon column
that allows for separation and isolation of all proteinogenic amino
acids in a single step. To minimize contamination, we utilized a mixed-mode
ion-exchange column to further purify the isolated amino acid fractions.
Radiocarbon measurements of standard amino acids processed with this
method resulted in F14C values closely aligned with their
original F14C values. From these measurements, we calculated
the blank contribution to 1.0 ± 0.3 μg C with F14C = 0.6 ± 0.12, rendering this approach suitable for ultrasmall
samples with enhanced measurement reliability.