Related Experiment Video
Updated: Feb 10, 2026

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge
Published on: September 26, 2016
Electromembrane extraction of substances with weakly basic properties: a fundamental study with benzodiazepines
Linda Vårdal1, Elisabeth L Øiestad1,2, Astrid Gjelstad1
1Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway.
Aim:
Electromembrane extraction (EME) of weakly basic benzodiazepines was investigated (-1.47 < pKa < 5.01).
Materials & Methods:
96-well EME was performed with strongly acidic conditions in the acceptor solution using 250-mM trifluoroacetic acid to maximize ionization.
Results & Conclusion:
Recoveries more than 80% were obtained for analytes with pKa > 2, whereas EME was less efficient for substances with pKa < 2. The latter was trapped in the supported liquid membrane due to less acidic pH conditions in the acceptor solution close to the supported liquid membrane. EME followed by UHPLC-MS/MS analysis was evaluated from human plasma, and the results were in compliance with EMA guidelines. Both electrokinetic migration and passive diffusion contributed to mass transfer when performing EME of weakly basic analytes.
More Related Videos
Related Concept Videos
Weak Base Solutions
Titration Calculations: Weak Acid - Strong Base
For the titration of 25.00 mL of 0.100 M CH3CO2H with 0.100 M NaOH, the reaction can be represented as:
Weak Acid Solutions
Fundamental Attribution Error
Titration of a Weak Acid with a Weak Base
As a result, there is no simple...
Sedatives and Hypnotics Drugs: Benzodiazepines
Benzodiazepines work by enhancing the effects of the inhibitory neurotransmitter GABA. They bind to the GABAA receptor, increasing its affinity for GABA, which opens chloride...

