FAQ - Frequently Asked Questions

Here you'll find answers to our most asked questions. Still can't find quite what you're looking for, or have something we should know? Send us an email, we're happy to help!

• Q1: What’s the best way to concentrate large sample volumes?

  A1: Vivaflow® TFF cassettes are ideal for concentrating 0.1–5 L samples quickly and efficiently without complex process setups. With PES or Hydrosart® RC membranes in single-use or reusable formats, these cassettes achieve up to 50x concentration in 30 minutes (1L) or under 75 minutes (5L), with near-total recovery using a simple buffer rinse.

• Q2: How can I reduce protein degradation during concentration?

  A2: To minimize protein degradation, avoid high shear stresses and unsuitable buffers. Choose devices with high membrane surface areas and gentle flow paths, like Vivaflow®, which reduce stress and non-specific adsorption. Use diafiltration tools like Vivaspin® 20 for buffer exchange during the process.

• Q3: Which ultrafiltration method works best for virus concentration?

  A3: Choose a MWCO about one-third the size of your virus. For Lentivirus (~90 nm), a 300 kDa Hydrosart® RC membrane is optimal. PES membranes also perform well but may impact recovery slightly. Device, membrane type, and MWCO should be tested for each virus.

• Q4: How do I maximize protein concentration and recovery?

  A4:Match membrane type, MWCO, and device to your target protein. Pre-treat devices, control shear, and use dead-stop features to minimize loss. Sartorius offers a wide selection for various sample types—optimize conditions for best performance and highest recovery.

• Q5: Is there a risk of concentrating samples to dryness with Vivaspin®?

  A5: No, all Vivaspin® devices have integral dead-stops, with minimum volumes ranging from 5 - 350 µL. This ensures the highest concentration factors can be reached without the possibility of drying out the sample. In addition, the Vivaspin® Turbo devices feature angular dead-stop pockets, which make collecting every last microlitre of the retentate sample even more straightforward

• Q6:  Can Vivaspin® and Vivaflow® devices be sterilized?

  A6: All of these devices can be sanitized using 70% ethanol or with ethylene oxide (EO) gas treatment. However, no studies  have been carried out to confirm sterility after such treatments. Where it is important that residual DNA does not interfere  with subsequent processing or analysis, PCR Grade Vivacon® devices are available. These are treated in a validated EO process to inactivate trace DNA.

• Q7: Which membranes are available with the Sartorius ultrafiltration range?

  A7:There is a unique and comprehensive range of three ultrafiltration membranes to choose from. Polyethersulfone (PES) and regenerated cellulose (RC, including Hydrosart® RC) for general applications, and cellulose triacetate (CTA) typically  recommended for permeate | filtrate applications

• Q8: How should I select the optimum MWCO?

  A8:Typically choose a MWCO 1/3 the size of the target molecule MW. Options which recommend lower or higher MWCO selections typically feature pore matrices with looser or tighter structures, resulting in lower recoveries or slower processing  speeds. Sartorius membranes have a porosity specified to offer the best of both worlds - high target molecule recoveries and shortest concentration times

• Q9: Will Vivaspin® and Vivaflow® be compatible with my sample?

  A9:Sartorius lab ultrafiltration devices are primarily intended for biological samples, but can be used in environmental and industrial applications. Compatibilities of housing and membrane material must be considered. The Instructions For Use  for each device provides guidance on compatibility with some common laboratory reagents. Vivaspin® Turbo features more chemically resistant materials, which will typically offer broader chemical compatibility, when needed.

• Q10: Can I concentrate nucleic acid samples?

  A10:All devices are able to concentrate double and single stranded nucleic acids, based on strand length. However, for optimal recovery, we recommend to use Vivacon® devices, which have been specially designed with a horizontal Hydrosart® membrane, are reverse spin enabled for pipette-free sample recovery, and offered in PCR grade versions to prevent unwanted interference

• Q11: What are the sample capacities for each device?

  A11:Lab ultrafiltration devices are available for the concentration of samples with an initial volume from 100 µL to 5 L ƒ Vivaspin® 500: 100 - 500 µL ƒ Vivaspin® 2: 0.4 - 2 mL ƒ Vivaspin® Filtrate: 0.4 - 2.5 mL ƒ Vivaspin® Turbo 4: 2 - 4 mL ƒ Vivaspin® 6: 2 - 6 mL ƒ Vivaspin® 15R: 4 - 15 mL ƒ Vivaspin® Turbo 15: 4 - 15 mL ƒ Vivaspin® 20: 5 - 20 mL ƒ Vivaspin® 100: 20 - 100 mL ƒ Vivaflow® SU: 0.1 - 1 L ƒ Vivaflow® 50R: 0.1 - 1 L ƒ Vivaflow® 200: 0.5 - 5 L ƒ Vivacon® 500: 100 - 500 µL ƒ Vivacon® 2: 0.4 - 2 mL