The power of modern extraction techniques: A breakthrough in vitamin K extraction from human serum

As a representative of the lipophilic vitamins, vitamin K is one of the most difficult vitamins to analyze. Even modern approaches using mass spectrometry detection cannot be carried out without multi-step, timeconsuming, economically, and ecologically demanding sample treatment. These findings suggest an opportunity to develop new modern trends that could shorten and simplify the whole procedure, whereby emphasizing the processing of a large number of samples with an additional focus on more environmentally friendly techniques. We selected and compared the main types of both, modern and conventional approaches for vitamin K analysis in human serum including liquid-liquid extraction and solid-phase extraction on the one hand, as well as supported liquid extraction, PhreeTM phospholipid removal plate, miniaturized liquid-liquid extraction, and dispersive pipette extraction on the other hand. The different techniques were compared from an analytical perspective, including parameters such as recovery, limits of detection, and matrix effects, as well as from a non-analytical perspective, including time consumption, cost effectiveness, and manual labor required to perform the procedure. The modern techniques seem to have great advantages. Our results indicate that the PhreeTM phospholipid removal plate, and the miniaturized version of the liquid-liquid extraction are the best techniques. This work was also carried out to provide a guide for the extraction of vitamin K while determining it using the liquid chromatography-mass spectrometry technique, which may improve sample handling and help to remove potential obstacles in the future.