Problems with sub-p.p.b. mercury determinations: preservation of standards and prevention of water mist interferences

Stability of Mercury Dilute Aqueous Solutions: An Open Issue

“…In all the combinations of K 2 Cr 2 O 7 and HNO 3 checked, samples were still stable 1 month after preparation except when the oxidizing agent is present at 0.01% (w/w) with 1% (w/w) HNO 3 .…”

“…The preservation of Hg solutions greatly improves when K 2 Cr 2 O 7 is added in the presence of various amounts of HNO 3 . In all the combinations of K 2 Cr 2 O 7 and HNO 3 checked, samples were still stable 1 month after preparation except when the oxidizing agent is present at 0.01% (w/w) with 1% (w/w) HNO 3 .…”

“…Low pH values and high ionic strength limit the adsorption on the container walls. Therefore, the addition of strong mineral acids such as HNO 3 The problems mentioned above actually arose in the framework of the activities of the European Commission Reference Laboratory (CRL) for residue in animal meat and the environment appointed at the Istituto Superiore di Sanità (ISS) of Rome (8).…”

Distribution, speciation, and budget of atmospheric mercury

“…Only after this cleaning procedure were the ampoules filled with 100-150 ml of rain water, acidified with 10 ml of concentrated nitric acid, conserved with a preservation agent, and sealed for storage. To prevent mercury losses due to adsorption on the glass surface, 0.1 g of K2Cr207 was added as a preservation agent to the rainwater samples taken in Germany (Christmann and Ingle, 1976;Matsunaga et al 1979). Samples taken during the ships' expeditions were preserved in 100 ml of seawater with a known mercury content (Ambe and Suwabe, 1977).…”

Automated continuous monitoring of inorganic and total mercury in wastewater and other waters by flow‐injection analysis and cold‐vapour atomic absorption spectrometry

“…This procedure normally uses a discrete sample method in which all the mercury from a given volume of solution is swept through the absorption cell to produce a peak response. Many improvements to the method, Hawley and Ingle [3], Christmann and Ingle [4] have reduced the detection limit to 2 pg in a ml sample. This method is widely accepted as a standard for determining traces of mercury in aqueous solutions and is well documented.…”