Discover our latest applications featuring Direct Detect IR-based Quantitation:


FTIR protein quantitation outperforms colormetric assays
IR-based quantitation (A) provides accurate and precise results, even in presence of detergent (SDS) and reducing agent (DTT). Using the Direct Detect™ IR-based quantitation system, calculated concentrations for the BSA samples matched the prediluted standards (A). In comparison, the Coomassie Plus (Bradford) assay provided calculated concentrations that differed greatly in the presence of 1%SDS (B, not shown here), and the MicroBCA assay could not provide data in the presence of 50 mM DTT. (C not shown here). (click to enlarge)

IR-based Protein Quantitation Surpasses Colorimetric Assays and is Independent of Detergents, Reducing Agents, and Analysis Time

We compare infrared (IR)-based protein quantitation using the Direct Detect™ quantitation system to Bradford and bicinchoninic acid (BCA) colorimetric assays and show that IR-based quantitation provides accurate results, even in the presence of detergent or reducing agent. Also, unlike colorimetric assays, the protein concentration obtained from IR-based analysis is unchanged regardless of the time delay between assay and data acquisition.
FTIR lipid quantitation outperforms colormetric assays
Protein quantitation in presence of lipids within a complex cell lysate is possible because the most intense regions of lipid absorbance are spectrally distinct from the protein’s Amide I and Amide II signals.
The Direct Detect™ Biomolecular Quantitation System Exploits Membrane Technology to Enable Accurate, Infrared-based Detection.

In addition to demonstrating the Direct Detect™ Spectrometer’s accuracy and precision, this application note describes the principles behind protein quantitation using FTIR spectroscopy and demonstrates that the IR spectra of sodium dodecyl sulfate (SDS) and lipids in a complex cell lysate do not interfere with the protein Amide I signal used to quantitate proteins.

Applications Raw Data

Quantitation of long aliphatic chains
(e.g., phosphatidylserine, triglycerides and more):
Quantitation of long aliphatic chains
IR spectrum of group frequency region recorded for phosphatidilserine (red) and triglicerides mixture (blue). Strong signal from CH2 and CH3 groups at 3000-2800cm-1 will be used for quantitation of material containing long aliphatic chains (lipids, PEGs and/or biofuels). Click to enlarge.