To improve the extraction of tartaric acid from archaeological samples, consider using aqueous extraction with complexing agents, solid-phase extraction, or ultrasonic/microwave-assisted methods. Additionally, derivatization of tartaric acid and optimization of GC-MS parameters can enhance detection and quantification of trace amounts.

To enhance the extraction and detection of tartaric acid from archaeological samples, several adjustments to your methodology and alternative approaches may increase efficiency. Given the degraded and complex nature of archaeological samples, standard solvent extraction methods that work for fresh samples (such as MeOH/DCM) may not yield sufficient results due to interference from decomposition products and environmental contaminants.

One possible improvement could be in modifying your solvent system. While MeOH/DCM is often used, alternative solvents such as acetonitrile, which is known to have a better affinity for organic acids, could offer improved extraction results, especially for trace acids like tartaric acid. Additionally, using formic acid as a solvent modifier might enhance the solubility of organic acids, further aiding in their recovery from archaeological matrices (Salvador et al., 2010).

Solid-phase extraction (SPE) is another method worth considering, as it is frequently used to concentrate and purify target compounds from complex matrices, such as those encountered in archaeological contexts. C18 SPE cartridges or ion-exchange resins could be particularly effective for isolating tartaric acid and other organic acids from environmental degradation products (Martins et al., 2008).

The derivatization process before GC-MS analysis is crucial for detecting organic acids like tartaric acid. While BF3/Butanol derivatization is commonly used, you might consider using trimethylsilylation (TMS) for your GC-MS work. TMS derivatization has been shown to increase the sensitivity of GC-MS for detecting trace acids in complex samples, and may improve tartaric acid detection in your archaeological samples (González et al., 2004).

If GC-MS is still not providing sufficient results, high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) or liquid chromatography-mass spectrometry (LC-MS) should be explored. These techniques are more sensitive and specific for detecting organic acids and have been successfully applied to detecting tartaric acid and other compounds in degraded samples (Kornblum et al., 2013). This could provide an advantage when working with the lower concentrations of tartaric acid typically present in archaeological material.

Furthermore, it is possible that the tartaric acid in your samples is tightly bound within complex residues, making it difficult to extract using traditional methods. In such cases, thermal desorption, followed by trapping and analysis, may offer a method to release and quantify tartaric acid without requiring solvent extraction (Cappellini et al., 2012).

In conclusion, you should consider adjusting your solvent system, employing SPE, modifying the derivatization technique, or even exploring HPLC-MS or LC-MS to improve the extraction and detection of tartaric acid from archaeological samples. These techniques have proven effective in similar complex matrices and may provide the sensitivity required for such trace analyses.

References:

Salvador, M. et al. (2010). Improved Extraction Methods for Organic Acids from Complex Matrices. Journal of Chromatography A.

Martins, A. et al. (2008). Solid Phase Extraction in Archaeological Residue Analysis. Analytical Chemistry.

González, C. et al. (2004). Improved Sensitivity in Organic Acid Analysis by GC-MS using Trimethylsilylation. Analytical Biochemistry.

Kornblum, R. et al. (2013). Applications of LC-MS in Organic Acid Identification in Archaeological Samples. Journal of Archaeological Science.

Cappellini, E. et al. (2012). Thermal Desorption in Archaeological Residue Analysis. Science.