Operation of NanoShield® Trap

Once the trap column is connected to your UHPLC system, begin operation using 80-85% buffer B at a flow rate equivalent to the desired gradient flow rate for around 10 minutes, after which time the pressure should be stable. It is recommended that at least 1-2 gradients are run without sample injection before assessment of column performance using standards.

Standby and idle conditions

To optimise trap column lifetime and performance, it is recommended that the instrument continues to run at the desired operating pressure and ideally continues to run blank samples using mobile phase gradients typical of normal operation.

Recommended buffer compositions

Buffer A 99.9% MilliQ Water, 0.1% formic acid
Buffer B 99.9% Acetonitrile, 0.1% formic acid

Orientation

NanoShield® can be used for loading and elution in either direction (non-directional)

Trap column temperature
NanoShield® reverse-flush trap is designed to be operated at ambient temperature. If your LC supports trap heating, the trap can be heated allowing for higher flow-rates.

Column equilibration
Before each run the column should be re-equilibrated using a minimum of 4 column volumes of 100% buffer A. Trap column equilibration should be performed below 1000 bar.

Column cleaning

The recommended method for cleaning the NanoShield® is to flush with 85% B mobile phase for three column volumes, followed by re-equilibration with 1% B for two column volumes prior to the next injection. To rejuvenate a used NanoShield®, the column can be flushed with 85% B in both flow directions to help aid the removal of any particulates.

Trap Column Volume

NanoShield® 5cm X 100μm = 0.4uL

Loading capacity

Suggested: <200ng
Max: 1ug

For optimal results, it is recommended to load <200 ng onto the NanoShield®, although the maximum capacity is 1 µg. Loading capacity is determined by, and should not exceed the capacity of the analytical column. For optimal results, use the lower value between the recommended trap load and the loading capacity of your analytical column. For more information on loading capacity, see Sample Loading.

Pressure Loading

Depending on your LC system, samples can be loaded using a pressure limit or a set flow rate. The recommended loading pressure for NanoShield® is 1000 bar. Pressures above 1000 bar, if supported by your LC system, may cause peak tailing or other undesirable peak characteristics.

Sample Loading Flow

Loading flow rates depend on your LC system’s pressure limit or can be set between 3-15 µL/min. We recommend loading 5–10 times the trap column volume. For a NanoShield® 5 cm x 100 µm trap, this is ~2.5-5 µL. At 5 µL/min, 10 column volumes takes approximately 1 minute before switching the trap in-line with the analytical column.

Elution, Wash, and Re-equilibration
For elution, use the IonOpticks recommended gradients for your analytical column with the NanoShield® trap. Recommended example gradients for all columns are available here.

Add extra time onto the end of the gradient during the wash and re-equilibration steps to account for any delay introduced by extra volumes due to the NanoShield® trap and capillary lines.