A 20 mm butyl septum lot hit the packing line with shore A durometer at 48 instead of the 52 midpoint. The line ran anyway because the shift supervisor checked only the certificate, not the in-line reading. Four days later, 11,000 septa were scrapped after autosampler needle coring tests showed a 6.3% failure rate at 2.5 punctures above the rated count. That is what a vial septa factory controls on the line, or fails to control. The manufacturing process is not a single molding step with a ...

An HPLC run failed its system suitability at injection 47 of a 100-injection sequence. The internal standard area had drifted by 11.3%, and the retention time for the primary analyte had shifted from 6.42 to 6.58 minutes. The root cause was not the column, not the mobile phase, not the autosampler needle. It was a septum that had been re-punctured 41 times and had begun shedding PTFE microparticles into the vial. When a QC reviewer asks whether your consumables meet USP requirements for via...

Last spring a client sent me a chromatogram pack from a 96-hour sequence on an Aijiren . The first forty injections looked clean. By injection 70 the peak areas for their target analyte had dropped 18%, and by injection 90 the internal standard response was wandering enough that the reported concentrations were useless. They had replaced the column, re-prepped the mobile phase, and re-calibrated the autosampler. Nobody had looked at the cap. When I asked which septum was on the vial, th...