1. Solid Sample Extraction for Pesticides, PCBs,
PAHs and Dioxin/Furans Analysis using
Accelerated Solvent Extraction (ASE) System
Bhupander Kumar
Scientist
National Reference Trace Organics Laboratory
Central Pollution Control Board
East Arjun Nagar
Delhi-110032

2. Principles of Extraction
 Physical and chemical processes influence solid-liquid
extractions
– Diffusion
– Viscosity
– Surface tension
– Solubility
– Binding energy of physio-chemico sorption interactions

3. Principles of Extraction
 General improvement of chemical processes as temperature
increases
– Diffusion increases, viscosity decreases, surface
tension decreases, solubility increases, and solute
interactions with matrix are decreased
 “Like dissolves like” principle is important
– Polar solvent for polar analytes
 Particle size influences extraction rate

4. Common Sample Extraction Techniques
 Soxhlet
 Sonication
 Microwave
 Automated Soxhlet
 Accelerated Solvent Extraction

5. Comparison of Liquid Extraction Techniques
Techniques Sample Size
(g)
Solvent Vol.
(ml)
Average Extraction
Time* (hours)
Soxhlet 10 – 30 300 – 500 4 – 48
Sonication 30 300 – 400 0.5 – 1
Microwave 5 30 0.5 - 1
Automated Soxhlet 10 50 0.5 – 2
ASE 10 - 100 15 - 120 0.2 – 0.5
*Extraction times are based on a per sample basis. This estimate of
time does not include sample weighing, sample loading, or sample
concentration.

6. What is Accelerated Solvent Extractor
(ASE) ?
 ASE is a technique for extracting solid and
semi-solid samples with liquid solvents
 ASE Uses elevated temperatures (40- 200oC) and
pressures (1500-2000 psi)
 Uses small quantities of solvent and short
periods of time
-15 mL and 15 min for 10 g samples
 ASE can be used to replace Soxhlet, Sonication,
Boiling, Wrist Shaker, and other extraction
methods

7. Comparison of extraction for Dioxin and Furans
by ASE and Soxhlet
ASE Soxhlet
Sample size 4 – 10 grams 4 – 10 grams
Solvent Toluene Toluene
Solvent volume (ml) 15 250
Temperature o C 150 - 180 << Boiling point
Pressure 10 MPs Atmospheric
Time 2 x10 min 18 hours

8. Environmental
Matrices*
 Soils, Sludges, Sediments
 Plant and animal tissues
 Air Samples
– Glass filters
– Quartz filters
– Tenax resins
– Charcoal adsorbents
– PUF and XAD resins
 Essentially all solid or semi-solid
matrices analyzed for environmental
contaminants
* Pesticides, Herbicides, Semi-volatiles,
PAHs, PCBs ,PCDDs and PCDFs
ASE Application Areas

9. Food
Matrices
 Food contaminant analysis
– Pesticides
– Herbicides
– PCBs
– PAHs
– dioxins, etc.
 Component analysis
– Lipid content
– Flavors
– aromas, etc.
ASE Application Areas

10. ASE 350
ASE 200
ASE 300
Different
Models of
ASE

11. Solvent
Pump
Purge Valve
Oven
Nitrogen
Static
Valve
Collection
Vial
Extraction
Cell
Fill with Time (min)
solvent 0.5-1
Load cell
Static Extraction 5
Purge with 1 - 2
nitrogen
cycle
Heat and 5
pressurize
Extract Total (min)
ready 12 - 14
Flush with 0.5
fresh solvent
ASE Schematic

12. ASE 350
 ASE 350 automated extraction system for
solid and semisolid samples
 Extraction of 24 sample at a time in various
size of cells (1, 2, 10, 22, 34, 66, and 100 ml)
 Collection vessels are 60 and 250 ml size
 Three 2L solvents can be hold
 Temp. limit 4000 C
 Work at pressure of 1500 - 2000 psi
 Can use single solvents or gradient of solvent
 Typical extraction times of 15 min per sample
 Extraction solvent volumes of 40–150 mL
Solvents
Control panel
Collection tray with vessels
Extraction cells

13. ASE Extraction Cell

14. Cell Loading
 Add filter to cell
 Weigh sample
 Mix Sample with dispersant
– ASE prep DE or Ottawa sand
 Fill empty space with sand or DE
 Transfer sample to cell using ASE funnel
 Add surrogate or other tracer compounds
 Add filter (optional) and Cap cell
 Load cell in extraction tray

15. Extraction Cell in Cell Oven

16. ASE Operation
(run a sample)
 Check solvents and gases. 6 step start-up
 Prepare cells
 Load cells
 Load collection vials
 Select method or schedule
 Select vial or bottle
 Press start

17. Extraction Cell in cell tray
Collection vial in vial tray

18. Methods Optimization in ASE
 Sample preparation or pretreatment
– Grinding
– Dispersing
– Drying

19. Grinding
 Sample with larger particles should be ground
 Efficient extraction requires minimum particle size
generally < 0.5 mm
 Grinding can be done by mortar and pestle or electric
grinder and mills

20. Dispersing
 The aggregation of sample particles prevent efficient extraction
 Dispersing with samples that tends to compact in cell outlet
 Samples with fine particles can adhere tightly to each other under
high pressure
 Dispersing can be achieved by ASE Prep DE (Diatomaceous earth)
or Ottawa sand
 Sea sand is not recommended because it contains very small
particles which block system
 Run dispersing extraction blank to verify its cleanliness

21. Drying
 Wet sample prevent non-polar solvents from reaching the target analyte
 Sample drying prior to extraction is the way to handle wet samples
 Drying is normally done by adding ASE Prep DE
 Cellulose may be used for very wet samples like fruits and vegetables
 Magnesium sulfate is not recommended due to its melting at high temp.
 Sodium sulfate is also not recommended because it could solubilize and
can deposited in exit line
 Following ratios have been applied to various samples
 Sample that appear dry: 4 g sample to 1 g DE
 Sample that appear wet: 4 g sample to 2 g DE

22. Examples of Sample Preparation
Sample Type Sample preparation
Wet soil/sediment 10 g sample with 5 g
of ASE Prep DE or Ottawa sand
Fish tissue (80 % moisture) 3 g sample with 2 g
of ASE Prep DE or Ottawa sand
Fruit / vegetables 10 g sample with 5 g
of ASE Prep DE or Ottawa sand
or 2 g cellulose
Creams/lotions 2 g sample with 3 g
of ASE Prep DE or Ottawa sand
Ground polymer 1 – 3 g sample with 1 – 3 g
of ASE Prep DE or Ottawa sand

23. ASE Extraction Parameters
 Solvent
 Pressure
 Temperature
 Static Time
 Flush Volume
 Purge Time
 Cycles

24. Solvents
 Solvent must be able to solubilize the target analytes while
leaving the sample matrix intact
 For efficient extraction “Like dissolves like” principle is
important
 Solvent mixture of different polarities can be used to extract
broad range of compounds
 Solvents with aqueous buffers can be used in ASE
 Strong acids (HCl, HNO3,H2SO4) are not recommended, due to
their ability to react with the stainless steel in the system

25. Temperature
 Start at 100ºC or 20ºC below the analyte/matrix degradation point
 Run multiple extractions on same sample at 100º C
 Increase temperature to improve recoveries
 Be aware of thermal limitations of sample and analytes
 1000 C is better for pesticides, herbicides, PCBs and PAHs
 1500 C is better for Dioxin/furans

26. Pressure
 Start at 1500 -2000 psi
 Consider lower pressures for samples likely to compress
 For most samples pressure has no noticeable effect
 Maximum pressure is 2000 psi
 ASE 200, 300 and 350 are set at 1500 psi

27. Extraction Time
 Increased extraction time
– Allows longer time for analyte diffusion
 Improved recovery obtained with some samples
 Increased number of static cycles gives better results

28. Static Time Cycles
 Static extraction cycles
– Better to have multiple cycles than one long cycle
» Two 5-min cycles are good than one 10-min
cycle
» Five 2-min cycles even better

29. Flush Volume
 Solvent volume goes into cell
 Set at 60% of cell volume
 When used with multiple static cycle, flush volume per
cycle is the total % divided by the number of cycles
 1 cycle with 60% flush volume
 2 cycle with 30%
 3 cycle with 20%

30. Purge Time
 Purpose is to get solvent out of cell; no impact on
recovery of analytes
 Set purge time for 30-45 seconds per 11 mL of cell
volume (90-135 sec for 33-mL cell)
 Increase purge time for densely packed samples
 Increase purge time for non-volatile solvents
 Increase purge time for larger cells: 66-mL or 100-mL
cells

31. Achieve Selectivity
 Solvent choice
– Adjust polarity
 Selective sorbents
– Alumina for fat retention
 Temperature
– Higher temperature = more co-extractables
 Combinations of the above

32. Check ASE Extraction Parameters
 If recoveries are low:
1) Increase the temperature
2) Add static cycles
3) Increase the static time
4) Select a different solvent
 Diagnostic skill
– Rinse test
– Run three blanks: check weight of solvent collected
– RSD: 3% or less

33. ASE Parameters for
PCDDs/Fs and PCBs
Conditions PCDDs/Fs PCBs
Matrix Soil, sludge,
sed. Etc (10 g)
PUF Fish tissue
(10 g)
Sediment
(10 g)
Solvent Toluene Hexane Hexane Acetone/hexane
(1:1)
Temp. 1500C 1000C 1250C 1500C
Pressure 2000 psi 1500 psi 1500 psi 1500 psi
Heatup time 5 min 5 min 6 min 7 min
Static time 10 min 5 min 5 min 7 min
Flush volume 60 % 60 % 60 % 60 %
Purge time 125s 100s 100s 180s
No. of static
cycles
3 1 2 3

34. ASE Parameters for
Herbicides, Pesticides, and PAHs
Conditions Herbicides Pesticides PAHs
Matrix Soil, sludge, sed.
(10 g)
Soil, sludge, sed.
(10 g)
Soil, sludge, sed.
(7 g)
Solvent DCM/acetone
(1:2)
hexane/acetone
(1:1)
DCM/acetone (1:1)
Temp. 1000C 1000C 1000C
Pressure 2000 psi 1500 psi 1500 psi
Heat up time 5 min 5 min 5 min
Static time 5 min 5 min 5 min
Flush volume 60 % 60 % 60 %
Purge time 60s 60s 60 s
No. of static cycles 3 3 3

35. ASE Parameters for
POPs (pesticides, HCB, PCBs, PCDDs/Fs) with
Hexane, DCM, Acetone, Toluene
Conditions Pesticides &
PCBs
HCB PCDDs/Fs
Matrix Soil, sludge. Sediments, Dust, biological
Solvent Hexane/acetone
(1:1)
DCM/acetone
(1:1)
Toluene
Temp. 1000 C 1000 C 1500 C
Pressure 1500 psi 1500 psi 1500 psi
Heat up time 5 min 5 min 7 min
Static time 5 min 5 min 10 min
Flush volume 60 % 60 % 70 %
Purge time 100 s 100 s 120 s
No. of static cycles 2 2 3

36. ASE Parameters for
XAD - 2 (AMBERLITE) Resin
Conditions Cleaning Elution
Solvent Acetone (100%) - one extraction
Hexane/acetone (25:75) – one extraction
Hexane/acetone (50:50) – 3 extraction
Hexane/acetone (50:50)
Temp. 750C 750C
Pressure 1000 psi 1000 psi
Heat up time 5 min 5 min
Static time 5 min 5 min
Flush volume 150 % 150 %
Purge time 120 s 120 s
No. of static
cycles
5 3

37. Thank you for your attention!
bhupander_kumar@yahoo.com
42102378, 9212135238
GO WITH ASE TO SAVE TIME, ENERGY AND
ENVIRONMENT WITH ADEQUATE ACCURACY……!!