Increase process understanding 

In process development stage to accelerate product to market


Strengthen your process control 

With high quality and highly reproducible results

Reduce cycling time

By eliminating delays associated with off-line testing (yield, throughput, resource utilization)

Minimize risk 

With continuous monitoring throughout the process

GMP grade

316L stainless steel body is designed to be fully enclosed to withstand the harshest GMP manufacturing environments. Passed IP65, C1D2, CE marking.

21 CFR Part 11 & Annex 11 Compliant Software

CTech™ ViPER ANLYTX software platform enables SecureVPT settings for 21 CFR Part 11 and Annex 11 compliance.

Removable and interchangeable flow cells

Modular component design allows for increased scalability from development to laboratory to production with three different removable Flow Cell options:

3 mm Flow Cell volume: 0.6 mL

10 mm Flow Cell volume: 9.0 mL

22 mm Flow Cell volume: 46.0 mL

Process connectivity via barb, Luer, and compression fittings (included).

Connectivity/System Integration

Designed with three digital input channels, three digital output channels, and two analog output channels to allow for seamless integration.

Robust and Automated Zeroing

Ensures accurate zeroing and prevents window breakage.

Linear Range-Finder Technology

The FlowVPX System automatically identifies the linear region of the section data sets to verify the compliance with Beer-Lambert law.


On-site installation and training included with system purchase.

Specification sheet: View Document


  • Cary 60: 483 x 559 x 203 mm (22 x 8 x 19 in)
  • FlowVPX (fully assembled): 120 x 100 x 230 mm (4.72 (W) x 3.94 (D) x 9.06 (H) in) 
  • Computer (Dell Latitude Rugged Extreme Laptop, open): 343 x 305 x 305 mm (13.5 x 12 x 12 in)


  • Cary 60: 18.14 kg (40 lb)
  • FlowVPX Head (fully assembled): 4.08 kg (9 lb)
  • Computer (Dell Latitude Rugged Extreme Laptop): 3.63 kg (8 lb)

Spectroscopic Engine: Agilent Cary 60 spectrophotometer

Qualification Slope Range: 0.10 Abs/mm to 46 Abs/mm using NIST traceable slope standards

Qualification Slope Repeatability: ±2%

FlowVPX Mounting: Two mounting screws on base of instrument. Mounting stand available.

Maximum Pathlength: 5.000 mm

Minimum Pathlength Step: 0.001 mm

Cable Lengths: Delivery Fiber optic standard length 3 m (optional 6 m cable available upon request)

Cary 60 Power Requirements: 90 VAC–265 VAC, Frequency 47–63 Hz

FlowVPX Power Requirements: Power supply input 100 VAC–230 VAC, 50 Hz–60 Hz. VPX power input, 24 VDC, 0.6 A max current draw.

Protein A280

  • The FlowVPX in-line variable pathlength System can provide accurate measurements during the downstream process from 0.1 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.

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Drug-to-Antibody Ratio (DAR)

  • The FlowVPX System can be used to measure the DAR value of antibody drug conjugates (ADCs) in-line. The software allows the system to measure the ratio between the payload and the protein in real time.

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Operating System: Windows 10 compatible

Software Environment: ViPER™ v1.0.0 and Agilent WinUV Software Suite v5.1.0.1019 or newer

Required Computer Hardware: Repligen recommends:

  • Min Processor: Intel i5 (i7 preferred) 
  • Min Hard drive: 250 GB (SSD preferred) 

Support Services

Enjoy the benefit of year-round discounts and support. We offer one to three year service contracts for your SoloVPE System. Schedule a visit from a Repligen Analytics Representative to qualify your SoloVPE System.

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Application Services

Supplementary to our standard support options, application services 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. 

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FlowVPX Transmission Tool

CTech Variable Pathlength Technology Consumables

The quality of our Fibrette® Optical Components, sample vessels, instruments, and our service is unmatched.

View Consumables