Description
Whatman 31ET is suitable and widely used for Tc-99m Sestamibi QC when used with ethyl acetate. However, it should be combined with a second test (typically using SG TLC-100 + saline) to fully assess radiochemical purity, especially to distinguish Sestamibi from free TcO₄⁻.
0.7 x 7 cm Strip Format.
1 cm sample spot (black HB pencil) and 6.5 cm top solvent front line (pink Sharpie).
100 Strips/Pack
Tc-99m Sestamibi is lipophilic → moves with ethyl acetate to Rf ≈ 1.0
Free pertechnetate (TcO₄⁻) → also migrates to Rf ≈ 1.0
Hydrolyzed-reduced technetium (TcO₂) → stays at origin (Rf ≈ 0)
This setup allows to quantify insoluble Tc impurities, but not free pertechnetate (since it co-migrates with Sestamibi).
Two-Strip Method for Tc-99m Sestamibi QC:
| Strip | Stationary Phase | Mobile Phase | Purpose |
|---|---|---|---|
| 1 | Whatman 31ET | Ethyl acetate | Detects TcO₂ (stays at origin) |
| 2 | SG TLC-100 | Saline (0.9%) | Detects TcO₄⁻ (moves to front) |
