Standard mercury

It is interesting to note that exactly the same interference occurred for both organic and inorganic mercury standards, since methyl mercuric chloride does not directly react with sodium sulphide to form mercuric sulphide. Therefore the interference could not be the result of incomplete digestion of mercuric sulphide or CH3Hg+. 

Table 13.10 Recovery of mercury standards spiked with sulphide...

The Adsorption of Xenon on Mercury (Standard State r = 0.0608 dynes/cm.)... 

Li and coworkers synthesized the novel IL l-butyl-3-trimethylsilylimid-azolium hexafluorophosphate and demonstrated its utility for liquid/ liquid extraction of inorganic mercury. Using o-carboxyphenyl diazoamino p-azobenzene as a chelator to form a stable neutral complex with the metal ion, the authors demonstrated selective extraction into the hydrophobic IL phase [19]. When sodium sulfide was added to the IL phase, the mercury ion was back-extracted into the aqueous layer, providing an avenue for recycling the IL. The authors report extraction and back-extraction efficiencies of 99.9 and 100.1%, respectively, for a 5.0 pg/L aqueous mercury standard. The mercury detection limit was 0.01 ng/mL in water and the method was successfully applied to detecting trace mercury in natural water samples. 

Sample Analysis Place 25 mg of sample in a combustion boat, and cover it with 1 to 2 g of the fine, granular, anhydrous sodium carbonate prepared as previously described. Ignite the sample as described for the mercury standards, record the maximum response, and determine the amount of mercury in the sample by referring to the standard curve. 

Numerous standard or certified reference materials exist for verifying the reliability of new or modified methods, especially for total mercury standard reference materials for individual organomercury species can be more difficult to obtain. The existing methods for determining mercury in biological and environmental matrices are described more fully in the following sections. 

Water and snow Extraction of organic mercury immediately after sampling addition of organic mercury standards addition of KB and a benzene/ toluene mixture isolation and volume reduction of organic layer GC/AAS 4 ng (dimethyl mercury) 5 ng (ethyl mercury) No data Paudyn and Van Loon 1986... 

Figure 1-5. Flameless atomic absorption data for mercury standards.

Hydroxylamine sulfate, NHjOH SO4, for the reducing solution, 7.5 g/S Mercury standards... 

Once it had been determined that instrument response is independent of mercury species or matrix, any stable mercury sample, even a coal SRM, can be used to verify instrument performance on a daily basis. The solid samples seem to be far more stable than any mercury standard in a hydrocarbon matrix that we have prepared to date. 

Mercury standard, 1000ppm dissolve 1.3534 g of analytical grade mer-cury(II) chloride HgCl2 in water and dilute to 1 litre. To avoid adsorption by glass walls, keep the solution in a polythene bottle. 

Vukalovich, M. P., and Fokin, L. R., Thermophysical Properties of Mercury, Standards Press (USSR), 1972. 

A calibration factor (f) is obtained by repeated analyses of a pre-purged ordinary seawater sample which has been spiked with increasing amounts of mercury standard solution. The concentrations of the spiked seawater, c.g., 0.2, 0.5 and l.Ong/L of Hg, should cover the concentration range expected in the field. Between runs with spiked samples, the system blanks should be established, t.e., by applying the analytical procedure without any addition of mercury. 

GC has been used for the separation of Hg spedes and MC-ICP-MS to measure Hg isotope ratios. Krupp and Donard [11] coupled capillary GC with different MC-ICP-MS instruments via a home-made transfer line for the measurement of the Hg isotope ratios in two Hg species, Meng" " and IHg (Table 17.1). A T1 standard was added continuously to the plasma by using a T-piece for the cormection of the GC unit and the spray chamber with the plasma torch. The five most abundant Hg isotopes were measured simultaneously in the SPEX (IHg + spedes) and STREM (MeHg+ species) mercury standards. These spedes were first derivatized to Et2Hg and EtMeHg, respectively. Then the species were separated from one another using GC and introduced diredly into the MC-ICP-MS instrument, with which isotope ratios were measured based on the short transient signals obtained. 

HPLC-ICP-MS Established a method for simultaneous speciation analysis of selenium and mercury. Batch-wise elution using two different mobile phases that are suitable for selenium and mercury speciation leads to successful determination of both selenium and mercury standards in 30 min with good efhciency and resolution... 

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