Loss of Bromoform during VOA analysis

[markeith6172]

I am currently using an Aechon autosampler with a OI 4660 P&T connected to an agilent 6880GC and 5273MS. My issue is that we have recently lost sensitivity for bromoform. We have changed the sparger, transfer line from the auto sampler to the P&T and to the GC. We have also change the trap (#10) but bromoform is only recovering about 30%. Any suggestions would be appreciated. Thanks

[Steve Reimer]

Check your purge flow. Low Bromoform is a sign of incomplete purge.
Also, if you haven't done so yet, run the part b leak check on your 4660.

[Steve Reimer]

Check your purge flow. Low Bromoform is a sign of incomplete purge.
Also, if you haven't done so yet, run the part b leak check on your 4660.

[Caltech]

[quote="markeith6172"]I am currently using an Aechon autosampler with a OI 4660 P&T connected to an agilent 6880GC and 5273MS. My issue is that we have recently lost sensitivity for bromoform. We have changed the sparger, transfer line from the auto sampler to the P&T and to the GC. We have also change the trap (#10) but bromoform is only recovering about 30%. Any suggestions would be appreciated. Thanks[/quote]

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Henry

[Ron]

You may be losing bromoform in internal tubing inside the purge and trap or in the water managment fitting. I would suggest taking out the the water management fitting and sonicating in methanol. Dry in a oven for about an hour, reinstall, and see if the bromoform is back. If this doesn't help consider carefully removing the internal lines going from the sparge mount to the 6-port valve, 6-port to trap, and flush them with methanol, oven dry, and reinstall.

Are you using a 5 mL or 25 mL sparge volume?