Frequently Asked Questions

How many times can qEV columns be reused?

All columns except for the qEVsingle can be reused up to 5 times depending on the type of sample used. Please see the associated qEV User Manual for more information.

What type of blood collection tube should I use if I want to isolate EVs from blood products (plasma, serum, whole blood)?

There are many different types of blood collection tube available and the anticoagulant present in the tube can affect the functionality and quantity of EVs present in blood products. Please see our Technical Note on this topic by clicking here.

Can the qEV column be regenerated?

Columns can become clogged over time by samples with a high lipid content. Columns can be cleaned with 0.5M NaOH, however the effectiveness of this method will depend on the sample type being analysed. We recommend using a column no more than 5 times.

Why do some particles appear in the later fractions?

The speed of particles as they move through the column is heavily dependent on the resin type (pore size) and on the particle size. Particles that are smaller than the pores in the resin will enter the resin and their progress through the column will be slowed, hence they will appear in later fractions.

What column should I use for very small volumes of samples?

We recommend qEVsingle columns for sample volumes up to 150 µL. For more information on choosing a column type for your samples, please see our comprehensive qEV selection guide by clicking here.

What is the minimum sample volume that can be used?

The lowest sample volume that can be processed is 100 µL with the qEVsingle. Sample volumes smaller than 100 µL can be used, but this will result in the particle volumes being diluted more than 6-fold.

Is it possible to tailor fractions so that they correspond to a specific size profile?

No. The column length is not long enough to achieve this type of resolution effectively.

Is it possible that the protein fractions will contain exosomes?

Yes. Depending on the size of the resin pores, particles that are smaller than the pores will enter the resin and their progress through the column will be slowed. Hence, these particles may appear in later fractions.

Are qEV columns sterile?

No. qEV columns are treated with a 0.5% sodium azide solution prior to sale, but they are not considered sterile.

Is it possible that the fractions containing extracellular vesicles will also contain apoptotic bodies?

Yes. If the apoptotic bodies have a similar size profile as the target particles, then it is possible that they will be contained in the same fraction.

How do I know which fractions will contain my target particles?

The fractions containing your particles of interest will vary based on the column type and gel being used. Please refer to the relevant qEV User Manual.

It appears that my sample does not pass through the whole length of the column by the time that I start collecting EV fractions. Is this to be expected?

Yes. Most samples will contain significantly more protein than EVs. The protein, which is usually the visible component, is slowed down by the pores in the resin, whereas the majority of EVs pass through without entering the resin. Thus, while it appears that the sample has not passed the full length of the column, the EVs can be collected in the appropriate fractions.

My column appears to flow more slowly after the second use, is this to be expected?

Yes. Lipids, denatured proteins, and other contaminants in the samples can block and bind the column, causing the flow rate to slow. Washing the column with 0.5M sodium hydroxide can remove some of these contaminants, however the effectiveness will depend largely on the type of samples being analysed. We recommend using a column no more than 5 times.

Can qEV columns be used to clean EV samples after they have been incubated with fluorescent labels or antibodies?

Yes. Fluorescent labels and antibodies are much smaller than EVs, so any free label will be separated from the EVs.

Can qEV be used in a clinical setting?

No. qEV columns are for Research Use Only and should not be used in diagnostic procedures.

Are qEV columns ISO-13485 certified?

Yes, qEV columns are manufactured to the ISO-13485 standard. However, qEV columns are for Research Use Only and should not be used in diagnostic procedures.

What buffer should be used to store the column between uses?

The buffer that the column has been run with containing some form of antimicrobial compound such as sodium azide (0.05%).

What column should I use if I want to do RNA and DNA testing?

You can use any column size but we recommend only using a column once to avoid any cross-contamination. For this reason, the qEVsingles are often the most suitable.

How many columns come in a pack?

qEVsingle - 20 Columns
qEVoriginal - 5 Columns
qEV2 - 2 Columns
qEV10 - 1 Column
qEV100 - 1 Column

Do you offer volume discounts?

Yes. Please contact your local Izon sales representative but filling out the form at the bottom of the page.

How many fractions will I get with each column?

This will depend on the column type, the fraction volume, and the number of fractions you choose to collect. The smaller the fraction volume, the more fractions will be needed. Please see the qEV User Manual for more information.

What is the difference between the 35nm and 70nm columns?

This is the size particles that are excluded by the column resin. qEV-35nm columns exclude particles larger than 35nm and qEV-70nm columns exclude particles larger than 70nm.

The 35nm columns have an optimal recovery range of 35nm - 350nm, while the 70nm columns have an optimal range of 70nm - 1000nm.

For more information, please see our comprehensive qEV selection guide by clicking here.

What protein quantification method do you recommend?

We recommend a chromogenic protein assay for protein quantification, such as a Bradford or Lowry assay. The type you choose will depend on the sensitivity required for your application.

How do I determine which column I should use for my application?

Please see our comprehensive qEV selection guide by clicking here.

Does Izon have any information on sample preparation or collection prior to using qEV columns?

Yes. Please see our technical and application notes available on the Izon Support Centre.

What columns sizes can be used with the Automatic Fraction Collector (AFC)?

The qEVsingle, qEVoriginal, qEV2 and qEV10 can be used with the AFC.

What is the qEV1 column?

The qEV1 is a column which separates particles using size-exclusion chromatography. Column dimensions and resin volume have been optimised for the separation of 1 mL sample loading volumes.

Does this mean that I can load a 1 mL plasma sample directly onto the column?

Most ‘raw’ samples cannot be directly run on qEV columns without prior preparation steps. Once your sample has been appropriately prepared, then you can load 1 mL. Visit the Izon Science Support Centre for recommendations and protocols.

Why does column size matter?

Selecting the most optimal column size for your sample is important for maximising the purity of EVs in your sample.

Why was the qEV1 column created?

Many wanted a column that was optimised for 1 mL loading volumes – particularly those working with EV-RNA. Previously, however, our low-volume columns were only available for 150 µL (the qEVsingle), 0.5 mL (the qEVoriginal), and 2 mL (the qEV2) loading volumes.

What's wrong with loading 1mL onto the qEVoriginal?

The qEVoriginal is designed to support 0.5 mL loading volumes. If you load 1 mL onto a qEVoriginal, EV-protein separation will be suboptimal. This means that the separated volumes will contain a lot more protein than would be the case if you used a qEV1.

What if I load 1 mL onto a qEV2?

Again, separation will be suboptimal. You will be diluting your sample more than is necessary.

Why does the qEV1 perform so much better than the Legacy qEVoriginal, when loading 1 mL?

Two reasons: as explained above, the qEV1 has been optimised for a 1mL loading volume, whereas the qEVoriginal is for 0.5 mL. Also, the qEV1 uses a novel agarose resin which provides better separation than our existing Legacy columns.

What does the qEV1 look like?

The qEV1 is 1.8 cm taller (0.7 inches) than the Legacy qEVoriginal, as the column dimensions have been optimised to cater to the 1 mL sample volume using the new proprietary resin.

What's the difference between Gen 2 and Legacy columns?

Gen 2 columns are built with a novel, proprietary agarose resin. It performs a lot better than the resin used in our existing Legacy columns. The qEV1 joins the novel Gen 2 qEV range, alongside the qEVoriginal Gen 2.