NMR-milk metabolites and extraction methods
Purpose
This is an example study that showed how NMR can be used to study the component of milk and the influence of milk extraction methods
Materials
Micropipette
Eppendorf vials with lids
NMR tubes (5 mm)
Chemicals
2% Milk
Chloroform
Methanol
DI water
Software
Topspin 4.0, Amix 4.0, Matlab and Chenomx 8.7
Methods:
Two extraction approaches for milk samples
Method #1: Extraction with Methanol
Add 700 μL 2% milk into a Eppendorf vial
Add 700 μL methanol into the same Eppendorf vial
Close the lid of the vial
Vortex for 5 minutes
Centrifuge for 10 minutes (settings: 14.8 RPM Speed, temperature 5°C)
Collect aqueous layer and transfer into a new PCR vial (do not disturb non-aqueous layer)
Close the lid of vial
Centrifuge for 10 minutes
Open the lid of vial and place into the SpeedVac Instrument
Dry for 7 hours at room temperature
Add 700 μL of buffer into vial
Vortex for 5 minutes
Centrifuge for 10 minutes
Transfer 650 μL of sample into NMR tube
Put a lid/stopper on the NMR tube
Analyze sample on the NMR instrument
Method #2: Extraction with Chloroform
Add 700 μL 2% milk into a Eppendorf vial
Add 700 μL chloroform into the same Eppendorf vial
Close the lid of the vial
Vortex for 5 minutes
Centrifuge for 10 minutes (settings: 14.8 RPM Speed, temperature 5°C)
Collect aqueous layer and transfer into a new PCR vial (do not disturb non-aqueous layer)
Close the lid of vial
Centrifuge for 10 minutes
Open the lid of vial and place into the SpeedVac Instrument
Dry for 7 hours at room temperature
Add 700 μL of buffer into vial
Vortex for 5 minutes
If it is not dissolved, sonicate for 1 minute
Vortex for 10 seconds
Centrifuge for 10 minutes
Transfer 650 μL of sample into NMR tube
Put a lid/stopper on the NMR tube
Analyze sample on the NMR instrument
Analyze using the Bruker software:
Topspin simple analysis
Initial data analysis
This section was created by Ngan Nguyen, Undergraduate student, Department of Chemistry, NC A&T State University
Data were collected and processed by Ngan Nguyen and Kamirra Pearson, Undergraduate students, Department of Chemistry, NC A&T State University