FlowVPE/FlowVPX Application: Protein A280

可変パスレングス装置であるCTech™ FlowVPE®システムは、プロセス分析技術戦略の一環として、インラインリアルタイム濃度測定(A280)を実施できます。

Use CTech FlowVPE® System for Protein A280 measurement.

Getting accurate “QC grade” in-line concentration measurements can be difficult for a variety of reasons.


  • Current off-line measurements take significant sample manipulation and are very time-consuming. 
  • Current in-line measurements do not have a sufficient linear range to quantify concentration and are simply used for monitoring a rise in protein concentration.

The FlowVPE Solution

  • Provides accurate measurement during the downstream bioprocess from .1 mg/ml to more than 250 mg/ml for an antibody of EC 1.5. 
  • No need to remove samples for testing or disrupt production flow. 
  • In-line measurements using the FlowVPE can reduce hold times in production and allow for better process automation. 
  • Utilized in various stages of the bioprocessing workflow.

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The FlowVPX Solution

Our newest in-line VPT Solution for “GMP grade” manufacturing. CTech™ FlowVPX® System delivers high quality and highly reproducible results — enabling increased process understanding, improved cycle time, and reduction in process control testing efforts.

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Downstream Applications

Here are just a few of the applications that demonstrate the reliability and performance of the FlowVPE System.

Capture Chromatography — Protein A

The graph below shows a chromatogram from the FlowVPE used to measure the mass loading on a column and the mass eluting off a column.  It also tracks the breakthrough of the protein from the column.

FlowVPE is able to measure titer, loading mass and elution mass in real time, making it easy to calculate recovery percentage. As demonstrated below, the difference between the FlowVPE concentration pre- and post-column equals the harvest titer.


KBI Biopharma has had success using the FlowVPE System in dynamic binding capacity studies. The FlowVPE is extremely accurate at high concentration which means you can achieve a good reading on the breakthrough.


In UF/DF, the FlowVPE System allows you to measure real time concentration, eliminating the need for off-line sampling and ensuring accurate completion of your final concentration to adequately achieve your ideal drug concentration. 

In this study, we took samples out every few minutes, measured them via A280 with a gravimetric dilution and compared the results to the FlowVPE concentration signal.

Sample mABFlowVPE (mg/mL) Gravimetric (mg/mL) %Difference
1 14.6 14.6 0.4%
2 53.2 55.0 3.4%
360.4 62.6 3.7%
4 67.4 69.7 3.4%
5 109.9 110.9 0.9%
6 160.1 155.1 3.2%
7 213.0 212.1 0.4%
8 238.9 239.0 0.0%

Drug Product Manufacturing (Formulation)

During the dilution step the FlowVPE/X can be used to monitor the concentration and ensure the product hits the target prior to filling.

The FlowVPE/X is put in a recirculation loop during the process and can monitor throughout so that the risk of over dilution is avoided.

Application Services

Your success is our success

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