Current Trends Flashcards
What does FFF stand for
Field Flow Fractionation
What is the general principle of FFF?
separation field (various types) applied perpendicular to the flow of sample through a channel
creates PARABOLIC flow (unequal speeds in layers flowing thru)
particles ‘fight’ against crossflow with diffusion; smaller particles have bigger diffusion coefficient
small particles -> faster flow channels
large particles -> slower flow channels
elute out at diff. rates
There is a ____ flow pattern in FFF
parabolic
the crossflow separation field in FFF is _____ to the channel.
perpendicular
What are typical separation fields in FFF?
cross-flow stream temp gradient E potential centrifugal force gravitational force dielectrophoretic standing acoustic wave mag field
Where does the cross flow in ASYMMETRIC FFF come from?
diverted from main flow, as it exits through the semi-permeable membrane at the bottom
compare symmetric vs asymmetric FFF:
symmetric: cross flow enter through porous top; exit through bottom
asymmetric: only bottom membrane is semipermeable; top is IMPERMEABLE (cross flow comes from main flow)
What is AF4? (AsFIFFF)
Asymmetric flow field-flow fractionation
What is H5F?
hollow fibre flow field-flow fractionation
What is the cross flow pattern in H5F?
radial (flow diverted from main flow, goes outwards through semi-permeable membrane)
Typical dimensions of AF4 (thickness, width/breadth, length)
thickness: 50-500um
breadth: 2cm
tip to tip length: 25-90 cm
typical channel flow rate in AF4:
0.1-1 mL/min
What detectors are usually used with FFF? (5)
UV abs, fluorescence, RI, multiple-angle lase light scattering (MALLS), ICP-MS
the information collected from a FFF is called a _____. What are the y and x axis?
fractogram
y axis: detector signal
x axis: time (during separation)
What are the applications of FFF in food science?
NP analysis
fractionation/characterize food macromolecules + colloidal particles
polymer/biopolymer science
separate nanoemulsions
In analyzing milk protein aggregates with FFF, which would elute out first - individual particles or aggregates?
individual (smaller; more diffusion so faster flow rate)
Advantages of FFF vs other separation techniques? (6)
no stationary phase (no breakthru/sample loss)
much larger particle size range (0.01-100um)
works w/ aqueous and organic solvent carriers (versatile)
mild conditions (good for fragile compounds)
no shape change in particles
models are available
Can FFF replace any of the other separation techniques?
No
ex: GC works for smaller particle mass ranges than FFF
What does SPLITT stand for?
split flow lateral transport thin
What are ‘-omics’?
general term for broad discipline of science/engineering for analyzing interactions of biological info
focus on:
- mapping info
- find interaction relationships
- engineer networks/objects to understand + manipulate regulatory mech
- integrate various omic subfields
what are ‘foodomics?’
study food + nutrition related sub-omics to improve consumer well-being & health
genomics + epigenomics + transcriptomics + metabolomics + proteonomics…
What is ‘metabolomics?’
study of global changes in ENTIRE METABOLITE SET of cells/tissues/organs/organisms
What aspects of food science involve a metabolome?
animal/plant tissue
human tissue
microbes
food products
The typical metabolomics workflow:
1 . sample collection
- sample prep to extract metabolome
- Analytical platform: screen extract (LC/MS, CE/MS, GC/MS, NMR…)
- data treatment/stat analysis
- interpret results
T/F: NMR is a non-destructive technique
True
Which is best for identifying novel compounds? NMR, LC/MS, or GC/MS?
NMR
applications of food metabolomics:
food authenticity
characterize GM foods
discover new dietary markers
identify prohibited substances
