A new dried spot-based technique involving untargeted liquid chromatography coupled with high-resolution mass spectrometry was testing for characterizing foodstuffs.
Researchers from the National and Kapodistrian University of Athens in Greece used red wine to test a new dried spot-based technique for characterizing foodstuffs. Their findings were published in the Journal of Chromatography A (1).
To effectively monitor the quality of foods and natural products, which are complex matrices that contain various classes of compounds, advanced analytical techniques are required. However, current sampling and sample preparation steps are typically resource-intensive and tedious, posing significant challenges in food analysis along production and supply chains. Additionally, preparing samples prior to analysis meant to extract metabolites of interest involves additional steps and costs.
Dried spot microsampling on paper cards, which has typically been used for dried blood spots (DBS) in biomedical applications, has shown noteworthy advantages over other approaches for different applications, such as blood testing. This includes minute sample size, easy on-site sampling even in remote areas, and convenient sample transportation via regular post. According to the researchers, dried spot techniques applied in food matrices, otherwise known as Food-DS, could provide a solution to current challenges in quality monitoring. However, the dried spot format has been underutilized in food analysis, with such applications not having been used for characterizing food commodities for intrinsic quality assessment.
In this study, Food-DS was tested as an alternative format in food characterization. Untargeted liquid chromatography coupled with high-resolution mass spectrometry (LC–HRMS) was used as a powerful metabolite profiling tool, mainly due to its high resolving power and accurate mass measurements, primarily for profiling approaches. Further, LC-HRMS/MS is viewed as a powerful untargeted analysis platform, enabling the characterization of the complex chemical composition of food products, including the multiple classes of phenolic compounds. Integrating dried spot sampling techniques in untargeted LC–HRMS/MS workflows for food analysis could enable comprehensive characterization of foods in more resource-efficient manner.
The workflow involved volumetric microsampling of red wine on standard DBS paper cards, followed by automated card handling and extraction. The dried spot methodology was compared to conventional sample preparation methods for wine, including benchmark filtration and dilution, assessing similarity of chemical profiles. Various parameters were optimized for the analysis of wine dried spots in an untargeted context, evaluating extraction capacity and metabolite coverage, assisted by the dereplication results.
By using red wine as a proof-of-concept, the scientists established an efficient dried spot workflow for untargeted characterization by LC–HRMS. Further, the technique was successfully compared to conventional techniques, providing similar metabolite profiles. The developed methodology involves easy volumetric sampling of 10 µL of wine on standard DBS paper cards in conjunction with automated card handling and extraction.
Various experimental parameters were optimized to obtain high sensitivity and metabolite coverage through the dried spot technique. Overall, whole spot extraction with H2O/ACN 80:20 yielded the most promising results in an untargeted context. The proposed dried spot-based approach for food characterization was shown to be reproducibile and cost-effective. Sampling could be facilitated by non-expert users, even in remote locations, and samples can be transported via mail. While red wine was used to test this new microsampling approach, the researchers believe it can be used as a basis for dried spot-based characterization of other food commodities as well. This can help further holistic, accessible and resource-efficient quality assessment.
(1) Deli, I.; Tzimas, P. S.; Beteinakis, S.; Halabalaki, M. Introducing Dried Spot Techniques in Food Characterization: The Case of Red Wine. J. Chromatogr. A 2025, 1757, 466112. DOI:
