Measurement of Mercury in Water

[NoelF]

I have about 1.5 Ml of water with a low (parts per billion) mercury content. I intend to pass the water through a suitable medium to remove the mercury. Can anyone tell me if there is a simple test that will indicate a trend in the murcury content as the removal process proceeds? The test doesn't have to be quantitative.

 

[luissabate]

I´m also searching for a method.
I wondwer if there is any alternative to AA or ICP.
The cualitative method DIPHENYLCARBAZIDE have pD=5, that means 1:100000 (far away from 50 ppb).

Regards,
Luis Sabaté