title: Rediscovery and Revival of Analytical Refractometry for Protein Determination: Recombining Simplicity With Accuracy in the Digital Era.
abstract: Among "vintage" methods of protein determination, quantitative analytical refractometry has received far less attention than well-established pharmacopoeial techniques based on protein nitrogen content, such as Dumas combustion (1831) and Kjeldahl digestion (1883). Protein determination by quantitative refractometry dates back to 1903 and has been extensively investigated and characterized in the following 30 years, but has since vanished into a few niche applications that may not require the degree of accuracy and precision essential for pharmaceutical analysis. However, because high-resolution and precision digital refractometers have replaced manual instruments, reducing time and resource consumption, the method appears particularly attractive from an economic, ergonomic, and environmental viewpoint. The sample solution can be measured without dilution or other preparation procedures than the separation of the protein-free matrix by ultrafiltration, which might even be omitted for a constant matrix and excipient composition.
authors.affiliation: Analytical Biochemistry, Analytical Services & Sciences, Process Science and Technical Operations, Baxalta Innovations GmbH, Wien/Vienna, Austria.
authors.forename: Heinz
authors.initials: H
authors.lastname: Anderle
authors.affiliation: Analytical Biochemistry, Analytical Services & Sciences, Process Science and Technical Operations, Baxalta Innovations GmbH, Wien/Vienna, Austria. Electronic address: alfred.weber@baxalta.com.
authors.forename: Alfred
authors.initials: A
authors.lastname: Weber
mesh_terms: D005079:Excipients / Q000737:chemistry; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D012031:Refractometry / Q000379:methods*; D012709:Serum Albumin / Q000737:chemistry
chemical_list: D005079:Excipients; D007074:Immunoglobulin G; D011506:Proteins; D012709:Serum Albumin
keywords: IgG antibody; albumin; analytical biochemistry; analytical chemistry; mAb; refractive index