Mercury Limit Test

AAS is used in a number of limit tests for metallic impurities, e.g. magnesium and strontium in calcium acetate palladium in carbenicillin sodium and lead in bismuth subgallate. It is also used to assay metals in a number of other preparations zinc in zinc insulin suspension and tetracosactrin zinc injection copper and iron in ascorbic acid zinc in acetylcysteine lead in bismuthsubcarbonate silver in cisplatinum lead in oxyprenolol aluminium in albumin solution and calcium, magnesium, mercury and zinc in water used for diluting haemodialysis solutions. 

Mercury Determine as directed under Mercury Limit Test, Appendix TUB, using the following as the Sample Preparation Transfer 2.0 mL of sample into a 50-mL beaker add 10 mL of water, 1 mL of 1 5 sulfuric acid, and 1 mL of a 1 25 potassium permanganate solution cover with a watch glass boil for a few seconds and cool. 

Mercury Determine as directed under Mercury Limit Test, Appendix NIB. 

Standard Preparation Prepare as directed under Mercury Limit Test, Appendix IIIB, using 1.0 mL of the stock solution, equivalent to 1 jxg of mercury, instead of the 2.0 mL specified therein. 

Procedure Continue as directed in Procedure under Mercury Limit Test, Appendix IIIB. Any absorbance produced by the Sample Preparation is not more than half that produced by the Standard Preparation, indicating not more than 0.1 mg of mercury per kilogram of sample. 

Standard Preparations Prepare a solution containing 1 pig of mercury per milliliter as directed for Standard Preparation under Mercury Limit Test, Appendix IIIB. Pipet 0.25, 0.50, 1.0, and 3.5 mL of this solution, respectively, into each of... 

Apparatus Use a Mercury Detection Instrument as described and an Aeration Apparatus as shown in Fig. 16 under Mercury Limit Test, Appendix IIIB. For the purposes of the test described in this monograph, the Techtron AA-1000 atomic absorption spectrophotometer, equipped with a 10-cm silica absorption cell (Beckman Part No. 75144, or equivalent) and coupled with a strip chart recorder (Varian Series A-25, or equivalent), is satisfactory. 

Loss on Drying Determine as directed under Loss on Drying, Appendix IIC, drying a sample at 105° for 16 h. Mercury Determine as directed in Method II under Mercury Limit Test, Appendix IIIB. 

Lead Determine as directed under Lead Limit Test, Appendix IIIB, using 2 pig of lead (Pb) ion in the control and the following as the Sample Solution Dilute an accurately weighed amount of sample equivalent to 1 g of sodium hydroxide, calculated on the basis of the Assay, with a mixture of 5 mL of water and 11 mL of 2.7 N hydrochloric acid. Mercury Determine as directed under Mercury Limit Test, Appendix IIIB, preparing the Standard Preparation and the Sample Preparation as follows ... 

FIGURE 16 Aeration Apparatus for Mercury Limit Test. 

Acrylates and polyethylene affect most preservatives, including organic mercurials, phenolics, and benzoic acids. Leaching of hydroxyl ions from glass raises the pH and indirectly affects preservative activity. In this respect, glass must pass a limit-test for alkalinity. 

Pedersen et al. (1994) conducted a monitoring study to assess the levels of trace metals, including mercury, in table wine, fortified wine, beer, soft drinks, and various juices. These authors reported that in all samples tested, mercury concentrations were at or below the detection limit (6 g/L [6 ppb]). 

The Safe Drinking Water Act (SDWA) sets a limit for mercury—a toxin to the central nervous system—at 0.002 mg/L. Water suppliers must periodically test their water to ensure that mercury levels do not exceed 0.002 mg/L. Suppose water became contaminated with mercury at twice the legal limit (0.004 mg/L). How much of this water would have to be consumed to ingest 0.100 g of mercury ... 

The H-type cell devised by Lingane and Laitinen and shown in Fig. 16.9 will be found satisfactory for many purposes a particular feature is the built-in reference electrode. Usually a saturated calomel electrode is employed, but if the presence of chloride ion is harmful a mercury(I) sulphate electrode (Hg/Hg2 S04 in potassium sulphate solution potential ca + 0.40 volts vs S.C.E.) may be used. It is usually designed to contain 10-50 mL of the sample solution in the left-hand compartment, but it can be constructed to accommodate a smaller volume down to 1 -2 mL. To avoid polarisation of the reference electrode the latter should be made of tubing at least 20 mm in diameter, but the dimensions of the solution compartment can be varied over wide limits. The compartments are separated by a cross-member filled with a 4 per cent agar-saturated potassium chloride gel, which is held in position by a medium-porosity sintered Pyrex glass disc (diameter at least 10 mm) placed as near the solution compartment as possible in order to facilitate de-aeration of the test solution. By clamping the cell so that the cross-member is vertical, the molten... 

A waste is toxic under 40 CFR Part 261 if the extract from a sample of the waste exceeds specified limits for any one of eight elements and five pesticides (arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, endrin, methoxychlor, toxaphene, 2,4-D and 2,4,5-TP Silvex using extraction procedure (EP) toxicity test methods. Note that this narrow definition of toxicity relates to whether a waste is defined as hazardous for regulatory purposes in the context of this chapter, toxicity has a broader meaning because most deep-well-injected wastes have properties that can be toxic to living organisms. 

In contrast, the coupling of electrochemical and spectroscopic techniques, e.g., electrodeposition of a metal followed by detection by atomic absorption spectrometry, has received limited attention. Wire filaments, graphite rods, pyrolytic graphite tubes, and hanging drop mercury electrodes have been tested [383-394] for electrochemical preconcentration of the analyte to be determined by atomic absorption spectroscopy. However, these ex situ preconcentration methods are often characterised by unavoidable irreproducibility, contaminations arising from handling of the support, and detection limits unsuitable for lead detection at sub-ppb levels. 

The analytic principles that have been applied to accumulate air quality data are colorimetry, amperometry, chemiluminescence, and ultraviolet absorption. Calorimetric and amperometric continuous analyzers that use wet chemical techniques (reagent solutions) have been in use as ambient-air monitors for many years. Chemiluminescent analyzers, which measure the amount of chemiluminescence produced when ozone reacts with a gas or solid, were developed to provide a specific and sensitive analysis for ozone and have also been field-tested. Ultraviolet-absorption analyzers are based on a physical detection principle, the absorption of ultraviolet radiation by a substance. They do not use chemical reagents, gases, or solids in their operation and have only recently been field-tested. Ultraviolet-absorption analyzers are ideal as transfer standards, but, as discussed earlier, they have limitations as air monitors, because aerosols, mercury vapor, and some hydrocarbons could, interfere with the accuracy of ozone measurements made in polluted air. 

According to the vendor, Cement-Lock technology has successfully removed polycyclic aromatic hydrocarbons (PAHs), PCBs, and tetrachlorodibenzo-1,4-dioxin (TCDD)/2,3,7,8-tetra-chlorodibenzofuran (TCDF) from soils and sediments in bench-scale tests. Metal concentrations were also reduced below detection limits in bench-scale tests. These metals included arsenic, cadmium, chromium, lead, nickel, mercury, and silver. 

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