DPX + SALLE
Combining Dispersive Pipette XTRaction + SALLE (Salt Assisted Liquid-Liquid Extraction) for a novel cleanup mechanism
Method Overview
XTR tips can house sorbents like weak anion exchange (WAX) or reverse phase (RP) for cleanup and the salt (S) necessary for SALLE. Example: WAX-S or RP-S tips.
- Salt dissolves in solution during aspirate/ dispense steps and acetonitrile separates due to increased ionic strength
- Solution can be analyzed directly, diluted or solvent evaporated and reconstituted in LC mobile phase depending on the workflow/application
- Ideal for applications that require acetonitrile for protein precipitation and are focused on hydrophobic analytes
Customize this method based on your workflow!
Generic Workflow
| 1a | Blood/Serum: Add I.S. + ACN Protein Precipitate Transfer Supernatant and add FA aqueous |
|---|---|
| 1b | Urine/ Oral Fluid/ Other: Add I.S. + ACN + FA aqueous |
| 2 | Aspirate/Dispense sample solution Transfer acetonitrile (upper) layer |
| 3 | Inject, dilute or solvent evaporate Injection volume can vary or can include a specific concentration/ dilution factor |
Benefits
- Automation friendly pipette tips eliminate need for offline liquid-liquid extraction
- This methodology works with a variety of biological matrices including: serum, blood, urine or saliva
- Amount of sorbent + salt customizable
- Workflow flexibility
- Minimize required matrix volume
- Provides sensitive quantitation and simplifies sample preparation
- Rapid extraction process – aspirate/dispense steps take seconds!
Clinical & Forensic Applications
| Matrix | Target Analyte | Products | Matrix Volume | Solvent Evaporation | Automation | Documents |
|---|---|---|---|---|---|---|
| Urine | THC & Metabolites | XTR tips: 20 mg WAX + 40 mg Salt | 200 µL | No | < 5 minutes | Simultaneous quantification of 11 cannabinoids and metabolites in human urine by liquid chromatography tandem mass spectrometry using WAX-S tips |
| Whole Blood | THC & Metabolites | XTR tips: 10 mg WAX + 20 mg Salt | 100 µL | No | < 2 minutes | Quantification of cannabinoids and their free and glucuronide metabolites in whole blood |
| Serum | Vitamin D | ToT Filtration for protein precipitation + WAX-S XTR tips | 75 µL | No | < 5 minutes | Automated Vitamin D Extraction from Serum |
| Urine/ Saliva | Cortisol | XTR tips: 10 mg WAX + 40 mg Salt | 100 µL | No | The application note follows a manual protocol but we can provide automation support for this method. | Rapid Sample Preparation for Quantitation of Cortisol from Saliva and Urine |