Detection and quantification of free amino compounds in selected agricultural by-products with derivatization followed by liquid chromatography-tandem mass spectrometry analysis

Abstract

Recuperating bioactive compounds and nutrients from agricultural by-products for livestock feed is a potential solution for their reuse. Three of the agricultural by-products whose potential needs to be further explored are hempseed (Cannabis sativa L.) hull and sea buckthorn (Hippophae rhamnoides) pomace and leaves. Free amino compounds content has not yet been explored for these samples and they were compared to oat (Avena sativa) bran and apple (Malus domestica Borkh.) pomace, since they have already been employed as livestock feed. For the analysis of amino compounds, the samples were derivatized with diethyl ethoxymethylenemalonate (DEEMM) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, in an approach called derivatization-targeted analysis. Overall, 46 free amino compounds were quantified, and a correlation matrix revealed that amino compounds’ profile of sea buckthorn leaves resembles that of oat bran, indicating that it is the most suitable agricultural by-product to be employed as feed supplement.

Keywords

• Feed supplement
• Free amino compounds
• Derivatization-targeted analysis
• Hempseed hull
• Sea buckthorn pomace and leaves