The Explorer Instrument

Component Products: Electroelute | Fractionate | Collect | Digest | Separate | Analyze



Our in-line protein filter system (PILFer) is a highly flexible protein filter that provides a one-step means of placing an untouched sample directly into a separation or purification process, delivering rapid and reliable results. Protea’s PILFer system uses in-line molecular weight cut-off (MWCO) filter membranes for fractionation and has two selectable ports. Researchers can achieve true in-line protein purification, desalting and/or concentration directly from any solution. The PILFer system saves time and prevents sample loss from concentration in off-line devices. When coupled with the Protea Explorer System switching valves, researchers can achieve rapid injection of purified, filtered samples directly into an LC column or MS


  • In-line format:  Minimizes transfer losses and contamination from sample handling
  • MWCO filters:  Allows selective MW fractionation
  • SDSaway: Permits removal of SDS detergent

Research Applications

The PILFer in-line protein filter system is recommended for applications where it is advantageous to directly inject samples into an HPLC or LC/MS system, including:  

    • Concentrating, purifying and desalting protein and DNA samples
    • Purifying recombinant proteins    
    • Separation of proteins by molecular weight
    • Removal of SDS detergent from protein samples using SDSaway reagent


Effective filter area


Filter storage temperature range

50 – 80°F (19 – 29°C)

Volume capacity

45 – 2000mL

Concentration capacity

100 – 100,000pmol

Filtration flow rate
(dependent upon MWCO filter used)

15 – 120mL/min

Filtration time

= (sample volume/flow rate) X 2

Retentate collection flow rate

150 – 400mL/min

Retentate volume

100mL minimum

Swept volume


pH range

1 – 14

Recovery yield


Mass spectrum of a PILFer fractionated mixture (upper spectrum) of the protein myoglobin and the peptides angiotensin I and somatostatin. The lower two spectra illustrate the effi cient fractionation of the mixture to remove the peptides (the fi ltrate) from the purifi ed protein myoglobin (the retentate) using a 10-kDa MWCO membrane.