1. Sample Preparation and Results

2. Results  Mean, Median, Average  Deviation from the mean  Absolute and Relative Measures: Relative = Absolute/Mean Value  Precision  Accuracy

3. Precision and Accuracy True Value ●●●●●● ● ● ● ● ● ● ● ● ● ● ● ● ● High Precision High Accuracy High Precision Low Accuracy Low Precision Low Accuracy Low Precision High Accuracy X ‾ ‾ X ‾ X ‾ X

4. Methods Sensitivity – ability to discriminate between small differences in analyte concentration Signal Amount

5. Methods Detection Limit – minimum concentration or mass of analyte that can be detected at the known confidence level Signal have to be 5 times bigger than background noise

6. Methods Dynamic Range (D R) DRDR Signal Concentration

7. Analytical Process Systematic Error Random Error Standards, Blanks

8. Results Rounding Off (5 round to nearest even digit) Significant digits (Error of measurement)  0.1% - 0.001 x value  Accuracy of measurement steps – defines significant digits

9. Samples and Results Sampling Representative Representative Homogeneous (Particles Size) Homogeneous (Particles Size) Number of Samples – Error of measurement Number of Samples – Error of measurement

10. Sample preparation

11. Solid – Liquid Extraction Matrix, solvent and analyte Matrix, solvent and analyte Solubility of analyte Solubility of analyte Interaction between solvent and analyte Interaction between solvent and analyte

12. Soxhlet Extractor 1 – solvent flask 2 – extractor 3 – solvent collector 4 - condenser

13. Extraction Factors affecting extraction: Factors affecting extraction:  Interaction between solvent and analyte  Distribution coefficient: K D = (m i /V) Solvent /(m i /V) Matrix Where: m i – mass of analyte V – volume of solvent and matrix  Volume of solvent vs. multiple extraction

14. Multiple Extraction (Oilseed) Solvent Volume Amount extracted Extracted (%) Single extraction 100 mL 0.75 g 75 Multiple extraction 20 mL 0.70 g 70 20 mL 0.26 g 96 20 mL 0.028 g 98.8 20 mL 0.009 g 99.7 20 mL 0.0015 g 99.85

15. Extraction Factors affecting extraction:  Interaction between solvent and analyte  Distribution coefficient: K D = (m i /V) Solvent /(m i /V) Matrix Where: m i – mass of analyte and V – volume of solvent  Volume of solvent vs. multiple extraction  Particles size

16. Liquid-Liquid Extraction

17. Distillation - extraction

18. GC – Sample Extraction with Solvents Methylene Chloride Ethyl Ether Carbon Disulfide

19. SPME – Solid Phase Microextraction SPME - Fused silica fibres (1 to 2 cm long) coated with various polymeric phase Equilibrium forms between the three phases: Fibre coating to sample phase Fibre coating to sample phase Headspace to sample phase Headspace to sample phase Fibre coating to headspace Fibre coating to headspace

20. SPME – Solid Phase Microextraction

21. SPME Fibres The commercial polymeric phases available are: Polydimethylsiloxane(PDMS)Polydimethylsiloxane/divinylbenzene(PDMS/DVB) Polyacrylate (PA) Carbowax/divinylbenzene (CW/DVB) Polydimethylsiloxane/carboxen (PDMS/CAR) Polydimethylsiloxane/divinylbenzene/carboxen1006 (PDMS/DVB/CAR) Carbowax/Templated resin (CW/TPR)

22. SPME Adsorption and Desorption http://www.chemsoc.org/exemplarchem/entries/2004/westengland_smith/ExempWeb/SPME.htm

23. SPE Solid Phase Extraction - Cartridges

24. Sample Preparation - SPE

25. GC – Derivatization with Silyl Reagents

26. END

27. Diagram of SPME Extraction Direct sampling SPME Headspace SPME

28. SPME - Adsorption