Separation of mercury from VOC’s and selective detection using gold film amalgamation and photoionization detection

Accepted for presentation at #ACSDenver 2015 on March 23, 2015:

PAPER ID: 2152487 
PAPER TITLE: “Separation of mercury from VOC’s and selective detection using gold film amalgamation and photoionization detection” 

DIVISION: [ANYL] Division of Analytical Chemistry
SYMPOSIUM: Advances in Analytical Separations 
PRESENTATION FORMAT: Oral 

Authors: J.N. Driscoll and J.L.Maclachlan, PID Analyzers, LLC Sandwich, MA USA

We used a sensitive but nonspecific photoionization detector (PID) with a 10.6 eV lamp to measure mercury that has an ionization potential of 10.43 eV. The PID responds to both mercury and VOC’s and the VOC’s have to be removed to make the technique specific for mercury. The chemistry of the gold/mercury amalgam makes this method specific for mercury and eliminates interference from VOC’s. This technique also concentrates the sample making the method sensitive to sub ppb levels. Mercury permeation tubes were used to generate levels from 0.02 to 1 ppm.

The method is applicable for both air and water samples. Air samples are collected and only the mercury is reacted with the gold surface. Any impurities are purged through, then the amalgam is heated to desorb the mercury which is measured by the detector. Water samples are analyzed using hydride generation with sodium borahydride to reduce the mercury salts to elemental mercury that is efficiently detected by the PID. The EPA MCL for mercury in drinking water is 2 ppb. The detection limit for Hg in water by hydride generation HGPID was 0.2 ppb.

See the rest of the Analytical Chemistry Division programming for ACSDenver 2015 here.