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Lecture 5 Sample preparation

See Harris Ch. 28. Lecture 5 Sample preparation. Making a fine powder is often necessary before digestion of extraction. Sample digestion. All organic compounds are destroyed Toxic elements determined via atomic spectra. Harris Chapter 28. High-pressure digestion (microwave is possible!).

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Lecture 5 Sample preparation

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  1. See Harris Ch. 28 Lecture 5 Sample preparation

  2. Making a fine powder is often necessary before digestion of extraction

  3. Sample digestion All organic compounds are destroyed Toxic elements determined via atomic spectra Harris Chapter 28

  4. High-pressure digestion (microwave is possible!)

  5. Microwave digestion or extraction

  6. OrganicCompounds Sampling Solid Optional protein precipitation Homogenize in buffer Liquid Optional protein precipitation • Isolation • Single step liquid-liquid extraction • Multiple step liquid-liquid extraction • Solid phase extraction • (pre)concentration DATA COLLECTION Data processing and interpretation

  7. Solvent extraction techniques

  8. Filters: Can be also used for Solid Phase Extraction

  9. Solid Phase Extraction cartridges

  10. Solid Phase Extraction

  11. Inside the SPE cartridge…

  12. polar non-polar

  13. Various sorption techniques: centrifuge positive pressure

  14. Large volumes:

  15. SPE extraction: Lots of junk removed!

  16. Microdiffusion (Conway) cell Preconcentration of volatile compounds

  17. Liqiud phase microextraction (LPME) A 1 mL drop at the end of a syringe needle. A simple device for headspace LPME. Stirring and thermostating are optional.

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