To deconvolve the effects of packed vs. free C18 coated particle material, a 96-well SPE plate was packed by Phenomenex (Sepra-SPE) with the amount equivalent to the optimized dry weight (5 mg/well). As illustrated by the violin plots in Figure , both Sepra-dSPE and Sepra-SPE yielded a greater number of LMWMs with mean recoveries at 100% or higher. Higher recoveries can potentially be explained by the Sepra methods having a greater capacity to extract LMWMs whilst simultaneously removing both protein and lipids. However, packing the Sepra particles in SPE format increases sample preparation costs. Of the four SPE plates tested (Hybrid-SPE, PHREE, ISOLUTE and OSTRO), Hybrid-SPE showed the poorest performance. The violin plots for the remaining three SPE methods demonstrated distributions of recoveries in the 50-100% range. Biphasic extractions are popular techniques used in the analysis of lipids on blood products. Folch, Bligh and Dyer (BD), and Matyash are the most commonly used extraction protocols . The aqueous phase produced in LLE also allows the measurement of polar metabolites from the hydrophilic fraction.