SoloVPE Application: Quantitation of Nucleic Acids (DNA/RNA)

The Alternative to Traditional Spectrophotometric Analysis: Analysis for nucleic acid quantitation and purity assessment (DNA/RNA)

Analysis for nucleic acid quantitation and purity assessment

The emergence of different high absorbance biotherapeutics modalities, such as oligonucleotides, presents a challenge in using traditional spectrophotometric methods for concentration measurements. 

Slope Spectroscopy® offers an excellent alternative to traditional spectrophotometric analysis for nucleic acid quantitation and purity assessment using A260/A280 ratio measurement. 

The SoloVPE Solution

  • Uses variable pathlength measurement data points to generate the slope within the linear region. 
  • Allows even highly concentrated samples to be measured without dilution and baseline correction. 
  • Saves time and produces reliable, reproducible results.

Application Case Studies

Case study #1 - Plasmid DNA Purity Ratio in Gene Therapy Products

Scientists at Pfizer, Inc. validated the determination of antisense oligonucleotides using the SoloVPE System. Simultaneous wavelength measurement enables automated calculation of Absorbance Ratio. There is no sample handling or sample prep, just direct measurement.

The variable pathlength allows R2 of ≥0.999 proving the system-to-system consistency is robust.

Case study #2 - Technique comparison for Oligonucleotide Concentration Determination

Scientists at Amgen, Inc. compared the oligonucleotide concentration between the SoloVPE System and the Thermo Scientific Nanodrop. Suitability of the instruments for high concentrations was assessed over a range based on maximum absorbance of the instrument (~2 AU). The nanodrop required dilution, while the SoloVPE System did not. This reduced the potential for dilution error and overall testing time.

For inline testing:

Using the same technology as the SoloVPE, consider the FlowVPX which can measure DNA/RNA concentration “inline” during a chromatography, UF/DF fill/finish, or mixing step.

Comparison of concentration measurement at multiple wavelengths using the SoloVPE system and the NanoDrop device.

Both instruments were able to determine the oligonucleotide concentration without dilution for the 3 mg/mL sample at 260 nm and 295 nm. However, the NanoDrop instrument required dilution to be under the 2 AU spectroscopic limit for 60 and 200 mg/mL samples. The NanoDrop was not able to read higher concentrations (>3 mg/mL) at the 260 nm or 295 nm wavelengths. This helped demonstrate that the SoloVPE provides a robust solution for oligonucleotide concentration determination to 200 mg/mL.

See Method Development and Evaluation of the Techniques for Oligonucleotide Concentration Determination


Revolutionary approach to UV-Vis measurements: SoloVPE® Slope Spectroscopy®

In this webinar, we will review VPT and how it can be used in various applications from protein therapeutics to gene therapy. We will share real-world case studies demonstrating how leading biologic companies have integrated the SoloVPE System into their manufacturing workflow for release and in-process testing.

Application Services

The passion for what we do is in the product and support services you receive

CTech is committed to our customers’ success. We design service offerings to supplement our standard support options and provide you with increased access to our highly knowledgeable and experienced professionals. We offer implementation, development, and educational guidance to maximize the benefits of your variable pathlength solutions and the Slope Spectroscopy® technique.

Application Services

  • 21 CFR Part 11 Guidance
  • Annex 11 Guidance
  • Validation Support
  • Qualification Service
  • Method Transfer Service


  • Method Design & Development
  • Comparability
  • On-Site Support
  • Custom Standards
  • Process Auditing


  • SOP Document Review
  • Advanced Slope Spectroscopy Training
  • Data Analysis
  • Maintenance & Troubleshooting

Contact a Bioanalytics Application Specialist

Your Partners in Method Development and Process Solutions.

Connect with our dedicated applications team. Our team can show you how to maximize the benefits of your variable pathlength solutions and the Slope Spectroscopy® technique. Let us help you expedite your SoloVPE Validation.

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