Sample Files

OPA Protein Quantitation

November 27, 2012


Related Products: Gen5 for Detection

Gen5 version required: 1.0 or higher

Basis for the Assay:

Quantitation of total protein content is a measurement common to many applications in basic science and clinical research. The compound, σ-phthaldialdehyde (OPA) in conjunction with reduced sulfhydryl groups reacts with primary amines to form fluorescent moieties. This compound reacts very rapidly, but is much more water-soluble than fluorescamine. The fluorescence intensity is directly proportional to the total protein concentration present in the sample.

The protocol calls for a fluorescence measurement using a 360/40 excitation filter and a 460/40 emission filter.

The experiment data file contains all of the fluorescence determinations for an OPA total protein determination using BSA as the protein.

Plate Configuration:

Plate configuration assumes that samples will be run in duplicate. Included is a standard curve of protein (0 to 1000 μg/ml). The plate includes 8 standard concentrations, but has no blanks or controls wells. Thus, 40 samples can be run on a microplate in duplicate, in addition to the standard curve.


The report is configured to provide the (1) raw fluorescence, (2) standard curve, and (3) calculated protein concentrations and statistics of unknown samples.