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May 10, 2020

5 frequently asked questions about Whatman products

By Joana Gomes, Laura Poli, Wernher Laufer, Support Scientists

We are filtering protein extract before loading on the ÄKTA system. How can I avoid clogging the Protein Prep syringe filters?

It seems to be a heavily loaded sample. To avoid clogging the Protein Prep syringe filters, you should first consider the sample volume.

You can try our GD/X line of syringe filters that incorporate a prefilter to filter viscous, dense or otherwise hard-to-filter material with high solids content. Each unit contains a prefiltration stack of Whatman Multigrade GMF 150 (10 and 1 μm particle retention rating) and Whatman GF/F to ensure that larger particles are captured before reaching the membrane.

We offer the following Whatman GD/X filters for hard-to-filter samples:

  1. GD/X 25 mm Syringe Filter, RC, 0.45 µm (Product code: 6882-2504)
  2. GD/X 25 0.45 µm CA (Product code: 6880-2504)
  3. GD/X 25 0.45 µm PES (Product code: 6876-2504)

If these are not suitable for your application, our GD/X 0.45 GMF uses a double glass fiber filter to retain fine particles down to 0.7 µm. If you are cautious about using glass fiber due to any potential non-specific binding or protein loss, Cytiva also offers Whatman GD/XP disposable syringe filters. These filters modify our GD/X line with a polypropylene prefilter stack to analyze samples that require inorganic ion analysis.

Note: Looking for a filter paper, membrane filter, or syringe filter? Let Cytiva help you find the optimal filter for your needs and ensure reliable analysis.

After applying the blood sample, how long can Whatman 903 Proteinsaver Cards be stored before analysis? What are the recommended storage conditions?

Whatman 903 Proteinsaver Cards are not intended for long storage periods. To minimize the possibility of degradation, we recommend storing blood samples dried on Whatman 903 Proteinsaver Cards at -20ºC in a sealed bag with a desiccant pouch.

We want to analyze fatty acid profiles (e.g., Omega 3, Omega 6) in human blood spot samples. Which type of product should we use?

Our Whatman 903 Proteinsaver Card is a 903-sample protein collection card with five sample spots for protein collection, transport, and storage.

These articles describe the use of our Whatman 903 Proteinsaver cards for similar applications, and could be a good starting point for your research: Measurement of the Omega-3 Index in Dried Blood Spots and Dried blood spot omega-3 and omega-6 long chain polyunsaturated fatty acid levels in 7–9 year old Zimbabwean children: a cross sectional study.

Note: Contact us if you need any samples of our cards to do preliminary trials.

What is the best filter for air filtration metal analysis?

Whatman QM-C quartz microfiber filter paper is our new high purity quartz filter. It features low trace metals and high temperature resistance. It is well-suited for heavy metal analysis of particulate matter and sampling of acidic gases, stacks, flues, and aerosols in air monitors.

What is a suitable syringe filter to use with a partially clarified sample prior to loading an ÄKTA chromatography column?

Protein Prep Syringe Filters for ÄKTA systems are designed to optimize protein sample preparation prior to chromatography. High yield protein purification and accurate protein analysis both depend on a quality sample being introduced to the chromatography column. The Protein Prep syringe filter has been designed specifically to optimize these outcomes, as they are equipped with a regenerated cellulose membrane with extremely low unspecific binding properties.

If you have any questions, you can contact us by filling out the form at the bottom of our support page. Alternatively, use our filter selector tool to identify a suitable filter material for your application.