The lot passed everything on the certificate: 45 Shore A, 0.060 in thick, 9.5 mm OD, siloxane extractables under the USP <381> threshold. Then the customer’s outgoing inspector pulled a 50-piece sample from the 20,000-piece shipment, found three septa with flash bridging the center hole, and rejected the lot on a single attribute. That rejection was correct under the plan, and it was also avoidable, because the flash had been there when the parts left the press. The gap was not ...

A customer sent back a lot of 200 septa last March because their QC reviewer rejected the certificate of analysis. The CoA listed the silicone durometer as 48 Shore A. The incoming inspection sheet, run on their own durometer, read 53. Same lot number. Same bag. The gap was five points, which is inside the A2LA scope of our supplier’s calibration but outside the customer’s internal tolerance of ±3. Their auditor asked one question: “Show me the calibration certificate for ...

A 40 °C GC run on a clean method threw a 2.1-minute peak at 0.8 ppm on a client’s FID, and it showed up in every blank. The method had been validated six weeks earlier. The autosampler had not changed. What changed was a lot of blue silicone/PTFE septa, and the ghost peak was a siloxane fragment the column had been re-concentrating on every injection. Ghost peaks from vial septa are not a mystery once you learn to read the bleed pattern, and the extractables profile of a septum is a f...