Compositions and methods for combining protein precipitation and solid phase extraction
A composition, method and device for the preparation of biological samples for subsequent LC-MS analysis using a combined and concurrent protein precipitation and solid phase extraction (SPE) process is described. Through an integrated combination of protein precipitation, filtration, and SPE using a novel zirconia-coated chromatographic media, interfering compounds, such as proteins and phosphate-containing compounds, are eliminated from the biological samples, affording a higher degree of analyte response during LC-MS analysis.
1. A solid phase extraction (SPE) media for the selective removal of phosphate-containing compounds from a biological composition prior to bioanalytical analysis, the SPE media consisting of:
a. silica substrate particles; and,
b. a transition metal oxide selected from the group consisting of zirconia and titania bonded onto the substrate particles;
wherein the transition metal is bonded onto the substrate through a direct bridging bond with the silica substrate particles, and wherein the SPE media bonds to the phosphate-containing compounds using a Lewis-acid interaction.
2. The SPE media of claim 1 , wherein the substrate is selected from the group comprised of porous silica, non-porous silica, and combinations thereof.
3. The SPE media of claim 1 , wherein the substrate particles have a particle size ranging between 10 nm and about 1000 μm.
4. The SPE media of claim 1 , wherein the substrate particles have a particle size ranging between 5 μm and 70 μm.
5. The SPE media of claim 1 , wherein the substrate particles are porous, and the pore size of the substrate particles ranges between 30 Åand 1000 Å.
6. The SPE media of claim 1 , wherein the substrate particles are porous, and the pore size of the substrate particles ranges between 60 Åand 400 Å.
7. The SPE media of claim 1 , wherein the substrate particles have a surface area ranging between 5 m 2 /g and 1000 m 2 /g.
8. The SPE media of claim 1 , wherein the substrate particles have a surface area ranging between 100 m 2 /g and 600 m 2 /g.
9. A solid phase extraction (SPE) media for the selective removal of phosphate-containing compounds from a biological composition prior to bioanalytical analysis, the SPE media consisting of:
a. porous silica substrate particles with a particle size ranging between 10 nm and 1000 μm, a pore size ranging between 30 Åand 1000 Å, and a surface area ranging between 5 m 2/g and 1000 m 2 /g; and,
b. zirconia bonded onto the outer surface of the silica substrate particles,
wherein the zirconia has an electrically neutral charge;
wherein the zirconia is bonded onto the outer surface of the silica substrate particles through a direct bridging bond with the silica substrate, and wherein the SPE media bonds to the phosphate-containing compounds using a Lewis-acid interaction.
10. The SPE media of claim 9 , wherein the substrate particles have a particles size ranging between 5 μm and 70 μm.
11. The SPE media of claim 9 , wherein the pore size of the substrate particles ranges between 60 Å and 400 Å.
12. The SPE media of claim 9 , wherein the substrate particles have a surface area ranging between 100 m 2 /g and 600 m 2 /g.