Gas chromatography–mass spectrometry-based quantitative method using automated solid-phase analytical derivatization for plasma levels of methylmalonic acid, total homocysteine, and related metabolites in Japanese Black cattle

抄録

High plasma levels of methylmalonic acid and total homocysteine are markers for vitamin B₁₂ deficiency, whereas high plasma levels of total homocysteine indicate folate deficiency in animals, including cattle. Although a combination of solid-phase extraction and derivatization is effective for analyzing plasma methylmalonic acid and total homocysteine, these procedures can be time-consuming, complicating large-scale analyses. To address this, we focused on automated solid-phase analytical derivatization (SPAD), because both solid-phase extraction and derivatization can be conducted automatically in a short timeframe. In the present study, we evaluated a gas chromatography–mass spectrometry- based quantitative method utilizing automated SPAD to determine plasma levels of methylmalonic acid, total homocysteine, and related metabolites in Japanese Black cattle. Compared to manual derivatization without solid-phase extraction, the SPAD demonstrated superior analytical quality for the quantification of methylmalonic acid, total homocysteine, and some related metabolites, possibly because of solid-phase extraction. Additionally, the SPAD requires less time. These results suggest that the presented quantitative method has the potential to precisely and practically evaluate folate and vitamin B₁₂ deficiencies in Japanese Black cattle.