Microvolume protein concentration determination using the NanoDrop 2000c spectrophotometer.

Area of Science:

• Biochemistry
• Analytical Chemistry
• Spectroscopy

Background:

• Traditional spectrophotometry methods often require large sample volumes, which is impractical for microvolume protein analysis.
• Cuvettes and capillaries used in conventional methods can be limiting for precise quantification of small sample amounts.

Purpose of the Study:

• To present an innovative spectrophotometer capable of quantifying microvolume protein samples.
• To demonstrate modifications to traditional protein determination methods for enhanced microvolume analysis.

Main Methods:

• Utilized the Thermo Scientific NanoDrop 2000c Spectrophotometer with its innovative sample retention system.
• Employed surface tension properties to hold microvolume samples (0.5-2 µL) between measurement surfaces.
• Applied absorbance readings at 280 nm (A280) and the bicinchoninic acid (BCA) colorimetric assay for protein quantification.

Main Results:

• The novel system enables quantification of protein samples in volumes as low as 0.5-2 µL.
• Elimination of cuvettes allows real-time path length adjustments, reducing measurement time and increasing the dynamic range.
• Reduced need for sample dilutions and simplified sample preparation procedures.

Conclusions:

• The modified spectrophotometry approach effectively quantifies microvolume protein samples.
• This method offers significant advantages in speed, dynamic range, and ease of use compared to traditional techniques.
• The NanoDrop 2000c Spectrophotometer provides a practical solution for microvolume protein analysis in research and diagnostics.