Whatman® Mini-UniPrep® syringeless filters with slit septa

PES, 0.2 μm, 1000/pk



polyethersulfone membrane
polypropylene housing (compatible with all major autosamplers)




biological samples requiring low protein binding media


cap (Split septa)
graduations: no
approximately 18 lb / 8.2 kg


pkg of 1000 ea


Whatman Article No. 28421721 (US reference)
Whatman US503NPEPES (1,000 ea)

filter capacity

400 μL

vial size

12 mm × 32 mm

pore size

0.2 μm


suitable for (standard robotics on HPLC instruments with sensitive needles, allowing for higher throughput; high throughput applications)

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General description

The Whatman® Mini-UniPrep® Syringeless Filters provide a faster and easier way to remove particulates from samples being prepared for High Performance Liquid Chromatography (HPLC)/ Ultra High Performance Liquid Chromatography (UHPLC) analysis. In fact, Mini-UniPrep lets you prepare samples in 1/3 the time required by other methods. Add up the time savings, plus the money saved from cutting multiple consumables out of the sample preparation process and you′ll see huge benefits for your laboratory.

Mini-UniPrep is a preassembled filtration device consisting of a 0.4 mL capacity chamber and a plunger. The plunger contains a filtration membrane at one end and a preattached cap/septum at the other. The plunger is pressed through the sample in the outer chamber and positive pressure forces the filtrate into the reservoir of the plunger. Air escapes through the vent hole until the locking ring is engaged providing an air-tight seal. Within seconds the Mini-UniPrep can be placed into any device able to contain 2 mL vials for injection into your instrument.

The device can be used either manually or with a compressor unit. The multi-compressor can process up to 6 samples at one time, further improving sample processing time and reducing the risk of hand stress. The Mini-UniPrep device is designed to fit into any autosampler accommodating 12 x 32 mm vials. Alternatively the septum can be pierced with a needle and the sample drawn off for manual injection into an analyzer.

Features and Benefits:
  • All-in-one filtration process allows you to process sample loads in 1/3 the time
  • Wide range of membrane choices from 0.2 and 0.45 μm pore sizes
  • Compatible with most major autosamplers
  • Fewer consumables required. Reduce costs by up to 40%


  • Routine HPLC/UHPLC analysis
  • Composite assays
  • Content uniformity
  • Protein precipitation
  • Solubility testing
  • Dissolution testing
  • Sample filtration

Continuous Improvement and Innovation:

Whatman has listened to customers and created a whole family of Mini-UniPrep filters to meet specific needs. Customers who need to filter light sensitive samples can use the Amber Mini-UniPrep, customers using robotics to maximize throughput can use Slit Septa Mini-UniPrep.

Amber Mini-UniPrep Syringeless Filter

Features and Benefits:
  • Amber color prevents photodegradation of light sensitive samples
  • Same colorant used in pharmaceutical containers designed to meet USP specifications for light resistance
  • Translucent amber chamber and plunger enable easy visual inspection

  • Use with any compound that requires protection from light, such as catecholamines or vitamins

Slit Septa Mini-UniPrep® Syringeless Filter

Features and Benefits:
  • Slit septum cap enables use with current robotics on HPLC instruments for high throughput automation
  • Durable yet flexible slit septum cap has been specially designed for instruments with sensitive sampling needs. Sample evaporation is minimal

  • Use with standard robotics on HPLC instruments with sensitive needles, allowing for higher throughput

Other Notes

Field of Use : For internal research use only. Products are not intended for diagnostic use or resale.

Legal Information

Mini-UniPrep is a registered trademark of Cytiva
Whatman is a registered trademark of Cytiva
Certificate of Analysis
Certificate of Origin

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