Lecture 5 Sample preparation

Lecture 5Sample preparation

See Harris Ch. 28

Making a fine powder is often necessary before digestion of extraction

Sample digestion

All organic compounds are destroyedToxic elements determined via atomic spectra

Harris Chapter 28

High-pressure digestion (microwave is possible!)

Microwave digestionor extraction

Sampling

LiquidOptional protein precipitation

SolidOptional protein precipitation

Homogenize in buffer

Isolation-Single step liquid-liquid extraction- Multiple step liquid-liquid extraction- Solid phase extraction- (pre)concentration

DATA COLLECTION

Data processing and interpretation

Organic Compounds

Solvent extraction techniques

Filters:Can be also used for Solid Phase Extraction

Solid Phase Extraction cartridges

Solid Phase Extraction

Inside the SPE cartridge…

polar

non-polar

Various sorption techniques:

centrifuge

positive pressure

Large volumes:

SPE extraction:Lots of junk removed!

Microdiffusion (Conway) cell

Preconcentration of volatile compounds

A simple device for headspace LPME. Stirring and thermostating are optional.

A 1 mL drop at the end of a syringe needle.

Liqiud phase microextraction (LPME)