Lesson 14 - Solid Phase Extraction II and other pre-treatment technique

Page 1: Introduction to Solid Phase Extraction

  • Lesson 14: Solid Phase Extraction II and other pre-treatment technique

Page 2: Non-Retentive and Retentive SPE

    1. Procedure of SPE

    1. Retentive and non-retentive SPE

    1. Application of SPE

    1. Derivatization

Page 3: Learning Objectives

  • After this lesson, students would be able to:

    1. Explain the operating procedures of SPE.

    2. List the types of SPE operation modes.

    3. State the application of SPE.

    4. State the application of derivatization.

Page 4: Overview of SPE Process

  • SPE is a 5-step process:

    1. Select the proper SPE tube or disk.

    2. Condition the SPE tube or disk.

    3. Add the sample.

    4. Wash the packing.

    5. Elute the compounds of interest.

Page 5: Detailed Steps of SPE - Steps 1 to 3

  • STEP 1: Select the Proper SPE Tube or Disk

  • STEP 2: Condition the SPE Tube or Disk

  • STEP 3: Add the Sample

Page 6: Detailed Steps of SPE - Steps 4 to 5

  • STEP 4: Wash the Packing

  • STEP 5: Elute the Compounds of Interest

Page 7: Selecting the Appropriate SPE Tube or Disk

  • Proper selection ensures effective extraction and prevents wastage of solvents or samples.

  • Selection is determined by sample volume used in the extraction process.

Page 8: Guidelines for SPE Tube/Disk Selection

  • SPE Tube Sizes:

    • < 1 mL: 47mm disk

    • 1 mL to 250 mL: 3 mL tube

    • 1 L: 90 mm disk

  • SPE Disk Sizes:

    • Recommended for large volume samples or when high flow rates are needed.

Page 9: SPE Equipment Description

  • ENVI-Disk™:

    • Solid Phase Extraction Disks

    • Diameter: 47mm

    • Recommended Storage: 15-30°C

Page 10: Conditioning the SPE Tube or Disk

  • Prepares sorbent surface for adsorption of analytes.

  • Condition by rinsing with one tube-full of solvent before sample extraction.

Page 11: Adding the Sample

  • Use the appropriate amount of sample to avoid destruction of sorbent surface and ensure good separation.

  • Samples must be in a form compatible with SPE.

Page 12: Enhancing Compound Retention

  • Adjust parameters to enhance retention:

    1. pH

    2. Salt concentration

    3. Organic solvent content

Page 13: Preventing Clogging

  • Pre-filter or centrifuge samples before extraction.

  • Control flow rate during extraction to affect compound retention.

Page 14: Washing the Packing

  • Wash off unretained materials using the original sample solution or an alternative that does not remove desired compounds.

  • Use a minimal volume of washing solution.

Page 15: Eluting Compounds of Interest

  • Use a small volume of solution to elute compounds of interest while retaining impurities.

  • Collect the eluate for further analysis or preparation steps.

Page 16: Solvents Used in SPE

  • Characteristics of solvents commonly used in SPE elution process discussed.

Page 17: Types of SPE

  • Retentive SPE:

    • Retention of target compounds.

    • Uses a less strong solvent for washing impurities.

    • Good for isolating analytes.

  • Non-retentive SPE:

    • Retention of impurities with weak solvents that only elute compounds of interest.

Page 19: Advantages of SPE

  • Prevents issues of liquid-liquid extraction:

    1. Incomplete phase separations

    2. Low recoveries

    3. Use of breakable glassware

    4. Disposing of large quantities of solvents.

Page 20: Benefits of Using SPE

  • SPE is efficient, yields quantitative results, rapid, and can be automated.

  • Reduces solvents and analysis time.

Page 21: Common Uses of SPE

  • SPE is used for:

    1. Cleaning up samples

    2. Concentrating analytes for sensitivity

    3. Exchanging sample environments for better chromatography.

Page 22: Introduction to Derivatization

  • Derivatization changes target compounds chemically, improving separation and analysis.

Page 23: Benefits of Derivatization

  • Enhances:

    • Volatility

    • Thermal stability

    • Polarity (usually reduces it)

    • Detectability by tagging compounds with different functional groups.

Page 24: Types of Derivatization Reactions

  • Silylation: Common for GC, adding silyl groups.

  • Acylation: Adding acyl groups for polar compounds.

  • Alkylation: Adding alkyl groups to compounds.

Page 25: Mechanism of SPE

  • SPE is based on the affinity of solutes in a liquid phase for a solid phase where impurities are washed away while retaining analytes.

Page 26: Types of Solid Phase Extraction

  • SPE methods include Reversed phase, Normal phase, Ion exchange (cation and anion exchange).

Page 27: Conclusion of the Lesson

  • Derivatization is an alternative to physical treatment, enhancing properties of target compounds for improved analysis.