Results

Dot-it-Spot-it^® Total Protein Assay

Standard curve for BSA

A. Semiquantitative detection by eye.
It is even possible by the naked eye to distinguish between 0 and 0.1 ng BSA per dot.

B. Quantitative detection.
The scanner Epson Perfection V600 Photo was used for quantification.
The graph shows BSA concentration in the sample vs. signal (blackness per pixel).
Detection limit in the sample: 0.18 μg BSA/mL .

Sample:
BSA (bovine serum albumin) standard was diluted between 0.2-20 μg BSA/mL in 0.03% Tween 20, 20 mM TRIS pH 7.5, 0.15 M NaCl.
Dot-it-Spot-it analysis:
Each 1 μL dot of application mixture contains 50% sample + 50% Dilution Buffer, 0.1-10 ng BSA per dot.

Comparing eight proteins using three total protein assays

Dot-it-Spot-it assay shows a mean protein-to-BSA ratio of 0.9,

just like the two first generation assays