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NIST Spectroscopic Measurement Standards.

Kenneth D Cole1, Paul DeRose1, Hua-Jun He1

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The National Institute of Standards and Technology (NIST) developed Standard Reference Material (SRM) 2082 for accurate pathlength calibration in UV absorbance measurements. This improves protein concentration determination using microvolume spectrophotometers and short pathlength cuvettes.

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Area of Science:

  • Biophysical Chemistry
  • Analytical Chemistry
  • Spectroscopy

Background:

  • Ultraviolet (UV) absorbance measurements are crucial for determining protein concentrations.
  • Microvolume spectrophotometers and short pathlength cuvettes are increasingly used for protein analysis, requiring accurate pathlength calibration.
  • Standard Reference Materials (SRMs) are essential for ensuring measurement accuracy and traceability.

Purpose of the Study:

  • To introduce and validate NIST Standard Reference Material (SRM) 2082 as a pathlength standard for UV absorbance measurements.
  • To assess the accuracy of pathlength determination using SRM 2082 with microvolume spectrophotometers and short pathlength cuvettes.
  • To enhance the accuracy and reliability of protein concentration measurements in biopharmaceutical analysis.

Main Methods:

  • Utilized NIST SRM 2082, a pathlength standard for UV absorbance.
  • Employed high-quality dual-beam spectrophotometers with short pathlength cuvettes.
  • Compared results with measurements from a microvolume spectrophotometer and a microvolume plate reader.
  • Validated pathlength calculations for short pathlength measurements.

Main Results:

  • SRM 2082 enables accurate calculation of pathlength values for short pathlength cuvettes.
  • Measurements using SRM 2082 demonstrated increased accuracy in subsequent protein concentration determinations.
  • Comparison showed good agreement between traditional spectrophotometers and microvolume instruments when using calibrated pathlengths.

Conclusions:

  • NIST SRM 2082 is a reliable standard for calibrating pathlengths in UV absorbance measurements.
  • Accurate pathlength determination using SRM 2082 enhances the precision of protein concentration measurements with microvolume instruments.
  • The use of SRMs like SRM 2082 and RM 8671 (NISTmAb) is vital for ensuring accuracy and reproducibility in the biopharmaceutical industry.