8 Flashcards
Solvent extraction?
Fractionation due to differences in water solubility and entropy (hydrophilic and hydrophobic properties).
Is there somewhere were there isn’t volatile?
No, there’s volatile everywhere.
!!! Dynamic headspace collection flow?
!!!Different types of volatile extraction? 2•
•Dynamic headspace collection flow
•
Chromatography?
Separation of mixtures into their components by exploiting differences in chemical properties, such as size, charge, and polarity.
Stationary phase?
When chemicals don’t go anywhere, such as solvent.
Load sample?
Loads chemicals, sometimes via pipetting.
Elution via mobile phase?
When solvent moves down into a test tube by elutting. Eventually, different chemicals drip down at different rates, and we capture them in different test tubes.
Retention times?
How long it takes until a compound fully drips down.
Chromatography steps? 4•
•Stationary phase (solvent)
•Load sample (chemicals studied as one mixture)
•Elution via mobile phase to measure retention time of different compounds)
•Elution of fractionations
Elation of fractionations?
Now we can analyze the chemicals after fractionation.
!!!Is solvent the same thing as chemicals in stationary phase?
Thin layer chromatography (TLC)?
When you measure fractionation but instead of retention time, you move the stationary compound and then you look at the retention index that is the distanced measured by the origin and revealed by sample colour or indicator dye.
When doing chromatography, what questions do you need to ask? 3•
•What is the stationary phase
•What is the mobile phase
•What is the detector
If you integrate retention index in terms of time, what do you get?
How much of that compound is in there.
You use gas chromatography when?
Compounds is in a gas phase.
High performance liquid chromatography (HPLC)?
When what you are interested in is not volatile. Stationary phase is a column or two variable packing. Mobile base is a gradient between two or more solvents.
What types of detector can you use in HPLC? 3•
•UV absorbance
•Refractive index
•Mass spectrum
Derivitization?
Figure out where the double bonds are.
Negative control?
Accounts for test area, handling
Positive control?
Standard response under test condition.
So if fractions of a large chemical didn’t work and has a similar effect/response to the control, then what do you do?
You ignore them since they are not the ones causing the change in organism response/behaviour.
What happens if all fractions do not produce the effect of the large chemical compound?
There is something wrong with your experiment and/or experimental methods.
!!!Attraction assays: olfactometers?
Allelopathy?
When compounds in the soil inhibit the growth of neighbours and other species.
Bioassays are the crucial step required to?
Provide the latter with the justification for identifying chemical agents.
