User:Omar Choudary/Notebook/Omar Choudary CHEM-571 AU-2011/2012/2012/02/29

From OpenWetWare
Jump to: navigation, search
BDLlogo notext lr.png Chem-571 Report.pngMain project page
Resultset previous.pngPrevious entry      Next entryResultset next.png


Objective

  • Perform FTIR with the following samples:

1. AuNP's with dye ( 70 and 166 Au/BSA ratio)

2. AuNP's without dye ( 70 and 166 Au/BSA ratio)

3. Solid BSA (Suitable as diluent in ELISA application, EMD Chemicals Inc.)

4. Solid Gold ( 99.9% Au, Fisher Scientific)

5. BSA and HCl with Dye

Description

  • Preparation of samples for FTIR beginning with background:

1. Grain KBr crystals to thin powder (Just KBr for background)

2. Use hand press to apply pressure on KBr sample to obtain transparent film (opaque film would block the laser)

3. Load into FTIR to obtain spectra.

  • Dried samples were mixed with KBr crystals by graining using mortar and pestle before being pressed into transparent film. Measured 5% sample relative to amount of KBr powder used.
  • FTIR was performed using Shimadzu-FTIR8300 with range of 600 to 4700 cm^-1 and 32 scans per spectrum.

Data

2-29-2012-1.jpg

Peaks at 3400 are due to the stretching vibration of –OH in BSA

Peak at 2350 is due to atmospheric carbon dioxide, explains why there are shifts in all the values

FTIR spectra of BSA alone in literature do not have these peaks

To accurately identify the peak around 1100 in the BSA/HCl with dye, we would need to look at the IR spectra of just dye alone

Its possible that the peak at 1100 is due to the amine that forms when the dye bonds to the BSA



2-29-2012-2.jpg


Other peaks characteristic of BSA and gold nanoparticles have been obscured by background

Peaks at 2350 are due to interference by atmospheric carbon dioxide

Peaks at 3350 are due to the stretching vibration of –OH in the BSA

Notes

  • KBr pellet was used to prepare samples because BSA isn't soluble in the more conventional solvents, ethanol or dichloromethane.
  • In theory there should be an observed shift in the lysine peak of the spectrum (because the dye is supposed to be linked to the lysine by changing the N-H bond structure).