Chromatography Forum

We recently had a refurb done on our OI analytical Purge and trap system for drinking waters. Previous to the refurb, the system had quenched acetone responses on the high end of the curve but little carryover (less than 2ppb) of acetone and small amounts of carryover of the end compounds ie. naphthalene. The range of the curve for acetone is 10-200ppb, all others .5-40ppb. After the refurb where the transfer line, trap, and sparge tube were replaced, we ran an ICAL. The curve was good for Acetone. However, after the HCAL the first blank has about 15ppb of acetone. Has anyone seen this before? We tried doing front inlet maintenance again but to no success. I did do a test with increased bake time but that was also unsuccessful.
We do a 40:1 split ratio. I am, unfortunately, not allowed to change that. Any suggestions would be greatly appreciated.

Possibly a cold spot between the transfer line and the inlet? I have some glass wool around that bit topped with some aluminum foil to keep that little expanse warm. Or check your water management.

We use a Tekmar 3000 with a VOCARB 3000 trap and keep the valve and transfer lines at 150C with the inlet at 200C. We purge at 70C to improve MTBE, Ketones, and recoveries beyond 4-BFB. Our cal curve goes from 20ppb to 480ppb. 40:1 split, 40C, and 1mL/min initial conditions. We have an RDL of 10ppb on a 20m x 180um x 1.2um DB-VRX column. But in general our blanks are always <5-9ppb.