Protein Quantitation Method
Analytical chemistry techniques for measuring extremely low concentrations of proteins allow for the precise monitoring of enzymatic processes in textile finishing. The micro bca assay utilizes a bicinchoninic acid formulation to detect protein levels as low as 0.5 micrograms per milliliter. This sensitivity is required when evaluating the removal of sericin or other biological residues from natural fibres.
Biochemical Mechanism
Reaction steps involve the reduction of copper ions from a divalent to a monovalent state in an alkaline environment containing protein molecules. The resulting cuprous ions then form a deep purple complex with the bicinchoninic acid. Within the micro bca assay, the intensity of this color change is measured using a spectrophotometer at a wavelength of 562 nanometers.
Technicians compare the absorbance values of the linen extract against a standard curve of bovine serum albumin. This comparison yields the exact protein concentration in the wash liquor or on the fibre surface. Reliable results depend on the elimination of interfering substances such as detergents or reducing agents that might distort the colorimetric reading.
Finishing Efficiency
Mills use this data to optimize the duration and temperature of enzymatic scouring. High levels of residual protein indicate incomplete cleaning which leads to uneven dyeing in subsequent steps. The micro bca assay provides the evidence needed to adjust enzyme dosages or liquor ratios.
