Supercritical Carbon Dioxide (sc-Co2) Extraction

LABORATORY MANUAL

ADVANCED FOOD ANALYSIS

PRACTICAL 1

SUPERCRITICAL CARBON DIOXIDE (SC-CO2) EXTRACTION

EXTRACTION OF SEAWEED USING SC-CO2

OBJECTIVE

1. To extract bioactive or targeted compounds.

APPARATUS AND REAGENTS

1. 60 ml stainless steel extraction vessel

2. Beaker

3. Collection tubes

4. Dried seaweed

5. Absolute ethanol (for flushing)

PROCEDURE

1)  20 g of samples was weighed and then was put inside 60 ml extraction vessel. The vessel was then fixed into extraction oven.

2)  The empty collection bottle was weighed and then attached at the collection part of the intrument

3) Incoming and outgoing tubes was attached at the bottom and upper part of the vessel, respectively.

4) The liquid CO2 cylinder was opened when the desired temperature achieved. The pressure was allowed to be achieved.

5) The ‘ON’ button was press at the booster when the temperature and pressure achieved.

6) The extract that come out was monitored and the extraction time was counted manually.

7) Before open the extraction oven, the pressure were released and the temperature was cooled down after the extraction

8) The collection tube was weighed(weight after) with the extract.

RESULTS AND DISCUSSION

Calculate the percentage of extraction yield using the formula given.

Moisture content, A (wet weight basis,%)

Moisture content, B (dry weight basis, %)         = 100 – A

Sample weight, C (dry weight basis, g)                 = B x SFE Sample weight* (g)

100

Yield (dry weight basis, %)                         = Weight of extract (g) x 100

C (g)

PRACTICAL 2

FOURIER TRANSFORM INFRARED SPECTROSCOPY – FTIR

ANALYSIS OF BETA-CAROTENE POWDER

OBJECTIVE

1. To identify the functional groups in IR spectra of standard compounds in Beta-carotene.

2. To identify the functional group present in Beta-carotene powder.

INTRODUCTION

PROCEDURES FOR SOLID SAMPLE

Mixing of sample with KBr

1. Agate mortar and pestle was removed  from the desiccator in the fume hood.

2. 1 mg of solid sample was grinded in agate mortar into powder for about 1 minute.

3. 80 mg of KBr powder was added into the sample powder and grind for about 30 second with pestle. Since KBr absorbs water, this procedure has to be done faster.

4. The mixture was scraped into the middle with the spatula .The mixture was grinded again for 15 seconds.

5. The mixture was heaped with spatula in the centre of mortar.

6. The KBr has to be kept back into desiccator.

Preparation of Kbr Pellets

1. One fourth (1/4) of the KBr mixture was taken and transfered into the collar of the handpress

2. The anvil was placed along with die pin. This procedure to ensure it comes into contact with the samples.

3. The die set was lifted carefully by holding the lower anvil and make sure the collars stays in place.

4. The handle of the handpress was opened until the upper ram of the handpress.

5. Handle was closed.

6. The dial pressure was rotated until the upper ram of handpress slightly touch the upper anvil on the die assembles.

7. The unit was tilt back  to hold the die set from falling off.

8. Then the handle was open.

9. The dial pressure was rotated clockwise in one half turn.

10. the mixture was compress slowly while closing the handle in 2 minutes.

11. The unit was tilted back. The handle was opened and the die set was removed from the unit carefully.

12. The pellet was weighed and inspected.

13. The collar containing the KBr pellet was placed onto sample holder.

14 the experiment was run using IR spectrum.

15. At the end of experiment, microspatula was used to remove KBr pellet from the collar.  By using the container labelled “Recover KBr Pellet”, the pellet was placed.

16. The metal apparatus was washed carefully with water and dry apparatus in oven.

OBTAINING SPECTRUM

1. The sample compartment of IR Spectrophotometer was checked and empty before use.

2. the spectrophotometer was operated by using the instruction provided.

3. For the start, the background spectrum has to be obtained.

4. the data acquisition was started after the sample was placed holder in the sample compartment and. The spectrum recorded has to be acceptable otherwise the new sample has to be prepare and repeat the procedure until acceptable spectrum was obtained.

SPECTRAL INTERPRETATIONS

1. structure the of compounds was draw and the spectrum for each compound was examined.

2. The major peaks in the spectrum was identified by using the structure of the compounds,

3. The functional groups was identified together with respective wavenumbers.

PRACTICAL 3

INDUCTIVE COUPLED PLASMA-OPTICAL EMISSION SPECTROSCOPY (ICP-OES)

DETERMINATION OF IRON AND CADMIUM IN PLANT TISSUE

OBJECTIVE

1. To determine the concentration of iron and cadmium in digested solution of plant tissue by

using calibration curve method.

2. To quantitate the amount of iron and cadmium in plant tissue in terms of percent weight

(w/w %).

INTRODUCTION

It has been 25 years since ICP optical emission spectrophotometers (ICP-OES) began to be widely used, and is now one of the most versatile methods of inorganic analysis. Its features are often compared to atomic absorption spectrophotometers. Compared to atomic absorption spectrophotometers, in which the excitation temperature of air-acetylene flame measures 2000 to 3000 K, the excitation temperature of argon ICP is 5000 to 7000 K, which efficiently excites many elements. Also, using inert gas (argon) makes oxides and nitrides harder to be generated.

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