This unit fully investigates the various aspects of practical SPE, as well as describing the basic principles and stages of method development in SPE. Included is an overview of troubleshooting SPE protocols, and specific advice for various problems that are routinely encountered. Basic principles of generic methods in SPE are also described. 

At the end of this module, you should be able to identify the optimum conditions for processing your SPE protocol – including various advanced concepts such as sorbent soak steps, evaluate the sorbent mass and geometry most appropriate for your method, approach SPE method development in a logical fashion and optimize your SPE protocol for maximum sensitivity and specificity, undertake troubleshooting procedures for various common protocol issues, and identify when the use of generic SPE methods might be appropriate and describe how mixed mode SPE might be used in this situation.

Topics include: 

• Sorbent column processing
• Centrifugal column processing
• Vacuum column processing
• Positive pressure column processing
• Sorbent bed geometry
• Disk products for SPE
• Disk based sorbents
• Fines and channelling
• SPE method development overview
• Analyte assessment
• Mechanism selection
• Sorbent screening - alternative sorbents
• Sorbent screening process
• Procedure optimization
• Soak steps
• Drying steps
• Elution optimization
• SPE method troubleshooting - overview
• Recovery problems
• Reproducibility problems
• Cleanliness problems
• Cleanliness problems - alternative solvents
• Cleanliness problems - poor sorbent selectivity
• Inadequate throughput
• Generic methods in SPE - overview
• Mixed-mode sorbents for generic methods
• Mixed-mode generic methods - overview
• Mixed-mode generic methods - basic protocol
• Mixed-mode generic methods - optimization