Protein concentration in each sample : C1V1 = C2V2

As absorbance increases along with the BSA concentration in both absorbances 1 and 2 at 595 nm, this would make the trendline a directly proportional curve which would have to begin at the origin.

Theoretically, based on the relationship that absorbance has to protein concentration, the graph is expected to go through the origin. However, because of experimental errors from equipment or technique, the general trend of the results/points on the graph might not allow the graph to pass through the origin

Accuracy is how close the set of measurements is to the true or known value.

For example, if in the lab you obtain a weight measurement of 3.2 kg for a given substance, but the actual or known weight is 10 kg, then your measurement is not accurate.

Reproducibility is the capacity of an experiment or calculation to be repeated under different circumstances and yield the same if not similar results.

During experiments, accuracy serves as a guide to avoid an observational error by setting a standard to achieve while reproducibility allows for the experiment to be reproduced by anyone and yield values close to the true value.

Bicinchoninic Acid (BCA) and the Lowry assay, both of which are burette methods of the assay, are two other methods that can be used to determine the protein concentration in a sample.

BCA Assay Method: BCA is a weak acid with two carboxylated quinoline rings that react with the purple product complexes formed between the copper and peptide bonds. Quantifying the concentration of a protein sample can be done by using its absorption spectra with the spectra of a known protein's concentration.

Lowry Protein Assay: In the burette, copper ions react with four nitrogen atoms from the peptides to form a cuprous complex. The side chains of tyrosine, tryptophan and cysteine produce a blue-green between 650 nm and 75 nm. Similar to Bicinchoninic acid, the principle of this method for protein concentration determination is to be able to determine very small (5 - 100 µg) quantities of protein in an unknown sample.