The bidirectional SPE (BD-SPE)
Bi-directional SPE – for difficult samples in the field of forensics and toxicology
| With the sample application method of bidirectional SPE (solid phase extraction) even difficult matrices such as B. brain tissue or similar matrices, automated and unattended 24 hours a day, 7 days a week. Cross-contamination can be excluded due to the process. |  |
The procedure of bidirectional SPE
The FREESTYLE system sucks the homogenized and buffered sample, e.g. B. brain tissue, over the top of an SPE column. The loading step, in which the matrix normally comes into contact with the robotics system, is carried out in the opposite direction. This means that the sample is not loaded onto the cartridge from above, but is sucked into the sorbent via the Luer tip. The sample passes through the sorbent and is then released in a “normal” direction into a dispensing glass, flowing through the sorbent a second time.
With this type of sample loading and unloading, the sample never comes into contact with the robot system itself, which means that carry-over from one sample to the next can be ruled out.
Unwanted matrix effects are minimized and the analyte can be eluted with minimal amounts of solvent. The sample originally used is collected in a vial directly next to the sample vial and is available to the user for further analysis if required.