Overview

AQ™ brand syringe filters are designed for high‑performance laboratory filtration and sample preparation. Most models within the AQ™ line suppor t bi‑directional flow, giving  users flexibility in orientation when filtering samples.

However, not all membrane types offer this capability due to differences in construction and internal pre‑filter design.

Bi‑Directional Flow Capabilities

All AQ™ Syringe Filters support bi‑directional flow, except:

• PTFE syringe filters
• Any syringe filters containing glass‑fiber pre‑filters

These exceptions exist because the internal structure of PTFE membranes and glass‑fiber pre‑filters is directional, meaning the pore gradient and mechanical layering are optimized for a preferred flow direction.

Important Note on Flow Performance

Even when a syringe filter is bi‑directional:

• Flow rates and resistance may differ depending on the direction of use
• This variation occurs because internal support layers, membrane geometry, and housing design may interact differently with fluid flow in each direction
• Therefore, filtration performance is functionally bi‑directional, but flow characteristics may not be perfectly symmetrical

For best consistency in analytical workflows, it is recommended to maintain a standard orientation once established, especially for sensitive HPLC sample preparation.

Ordering Information

Click HERE for AQ™ brand syringe filter ordering information and product images.