Serum protein analysis, Lowry method

Many physicochemical assays are established to quantify the protein mass. It is determined by exploiting the extinction coefficient in optical density measurements or by colorimetric assays such as the Bradford, Lowry, bicinchoninic (BCA), and biuret assay [13, 14]. Albeit easy to perform, these colorimetric assays suffer from inaccuracies that are due to the use of inappropriate standards like bovine serum albumin. If relevant standards are not available, quantitative amino acid analysis [6], the (micro-)Kjeldahl nitrogen method [14, 15] or gravimetry as very accurate but time-consuming alternatives can be applied. 

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