Rapid, Sensitive, and Quantitative LC/MS/MS Determination of Digitoxin and Digoxin in Plasma

The Next Generation in Hybridspe-Phospholipid Technology

Patent pending HybridSPE – Precipitation (HybridSPE-PPT) technology is a simple and generic sample prep platform designed for the gross level removal of endogenous protein and phospholipid interferences from biological plasma and serum prior to LC-MS or LC-MS/MS analysis. Biological plasma or serum is first subjected to protein precipitation via the addition and mixing of acidified acetonitrile. Precipitated proteins are then removed by centrifugation and the resulting supernatant is loaded on the HybridSPE-PPT 96-well plate or cartridge which acts as a chemical filter that specifically targets the removal of endogenous sample phospholipids. The phospholipid retention mechanism is based on a highly selective Lewis acid-base interaction between the proprietary zirconia ions functionally bonded to the HybridSPE-PPT stationary phase and the phosphate moiety consistent with all phospholipids. The resulting eluent is ready for immediate LC-MS or LC-MS-MS analysis. An alternative “In-well Precipitation” method is available for the HybridSPE-PPT 96-well version in which biological plasma/serum is first added to the 96-well plate followed by acidified acetonitrile (precipitation agent). After a brief mixing/vortexing step, vacuum is applied to the 96-well plate. Because the 96-well version contains a series of low porosity hydrophobic filters/frits, the packed-bed filter/frit assembly acts as a depth filter facilitating the concurrent removal of both phospholipids and precipitated proteins during the extraction process.