Erratic Aldrin Recovery EPA 525

[ravenwork]

Greetings,

Anyone out there have experience with aldrin recovery problems in EPA 525? We seem to have trouble in spiked water samples where aldrin is at low level while other compounds on the list are at high levels that require additional dilution. It is the primary run, without dilution, where aldrin fails recovery with low bias.

This is frustrating since aldrin is fine in our QC, including a low level laboratory control sample.

Anyone out had to deal with aldrin?

TIA,

Evan L. Cooper

[vballchemist]

I have some evidence of low aldrin recoveries out of samples but not consistent enough to track a hard and fast problem. We run 525.2 SPE on mostly clean drinking waters. Typically, %R @ 1ug/l spike recovers at >90%. Some sample spikes can be as low as 55%.

BTW - We have never had a need to dilute a sample for high contaminants. How do you dilute an extract, as the IS is added prior to extraction?

[ravenwork]

The dilutions I mentioned were performed prior to the extraction.

What SPE are you using?

ravenwork

[vballchemist]

We use the C18 EMPORE extraction disks.