Michael asks…
How would you extract organics from a cloth sample?
Would I put it any particular solvent, such as diethyl ether and repeat this 2 or 3 times. How would I get the final extract and how will identify compounds? NMR?
weight loss cardiff answers:
The first question to ask is the polarity of the organics. If they are non-polar (like oils), then non polar solvents (like hexane) should be used for the extraction. A sohxlet extractor does a good job with small amounts of material. Just evaporate the hexane after refluxing an hour or so. Polar substances can be dissolved in water but ethanol or ethyl ether can be used if the solvent needs to be evaporated quickly. A rotary evaporator does a good job with alcohols, ethers or ketones. Detection is easiest using HPLC (high pressure liquid chromatography). The chromatographic column needs to match the polarity of the solvent passing through it. C18 is a good polar material for use with water or alcohols. Silica columns are used with non-polar solvents such as hexane. GC (gas chromatography) is another option. The column is not quite as important as the detector. Electron capture detectors (ECD’s) are radioactive devices very sensitive to substances containing Oxygen or halogens. ECD’s are used in pesticide analysis. FPD (flame photometric detectors) are general purpose detectors and can be used with almost anything. Hall detectors are extremely sensitive to halogen containing compounds. Finally, there is Mass Spectroscopy. This works in conjunction with a chromatographic column, which separates compounds. The Mass Spectrometer then breaks molecules up into ions, and the weight percentages are very characteristic of individual compounds.
Richard asks…
How is chlorophyll (the color green) derived and is that molecular compound used in making of green products?
Chlorophyll is said to be the Molecular Formula C35,H28,O5,N4,Mg. Two solvents diethyl ether and acetone are used to extract Chlorophyll from a plant. Do they just drop a green leaf into a bucket of acetone and the color green comes out?
weight loss cardiff answers:
We would have to walk into a factory that makes these colors. Nothing is being said.
Sandy asks…
Organic substance extractions from aqueous solutions.. why do certain ethers work as solvents and others don’t?
How can diethyl ether be successful in extracting organic substances from aqueous solutions but not dimethyl ether or dioxane?
weight loss cardiff answers:
Diethyl ether . . . .
A.
Is almost nonpolar – – – > suitable for extraction of organic substances which are less polar than water
B.
Has limited solubility in water – – – > when mixed with water , separated aqueous – organic layers will be formed and enable extraction
C.
Has a low boiling point – – – > after extraction and separation of aqueous – organic layers , it can be easily evaporated / distilled out
Dimethyl ether . . . .
Is a gas at room temperature ( Boiling Point – 23.6 Celsius ) – – – > can not be utilized for extraction at room temperature
http://en.wikipedia.org/wiki/Dimethyl_ether
1,4-Dioxane . . . .
Is miscible with water – – – > Usage for extractions from aqueous solutions are not possible
http://en.wikipedia.org/wiki/1,4-Dioxane
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