Yes, our µPACᵀᴹ columns are fabricated by etching from a crystalline silicon wafer following lithographic definition of a pillar array. This means the µPAC™ columns consist of one piece of solid material and there is no risk from moving or breaking beads. The columns are completely symmetrical, do not contain any frits and every chip is identical. Therefore, our customers have experienced that the µPACᵀᴹ columns are very robust and highly-reproducible when compared to traditional columns. We have run an experiment where a µPACᵀᴹ column on one of our nanoLC instruments was continuously used for 6 months. We performed serial injections of a tryptic digest of cytochrome C, followed by a tryptic digest of HeLa cells, followed by a blank. After a total of 3,500 injections, no effect on the retention time or pressure profile was apparent. More information is provided in our technical note on column robustness.
Can I use the µPAC™ column in both directions?