Atomic absorption spectroscopy, water analysis

Atomic absorption spectroscopy is an alternative to the colorimetric method. Arsine is stiU generated but is purged into a heated open-end tube furnace or an argon—hydrogen flame for atomi2ation of the arsenic and measurement. Arsenic can also be measured by direct sample injection into the graphite furnace. The detection limit with the air—acetylene flame is too high to be useful for most water analysis. 

Analysis of Corexit 9527. Corexit 9527 in natural waters can be analyzed. The method is based on the formation of a Z>w(ethylenediamine) copper(II) complex, extraction of the complex into methylisobutylketone, and atomic absorption spectroscopy [1564]. The method is suitable for a concentration range of 2 to 100 mg/liter, with a precision as low as 5% relative to standard deviation for samples in the middle- to high range. Only a small sample volume (10 ml) is required. The sensitivity may be substantially increased for trace analysis by increasing the sample volume. 

Parker, C.R., Water Analysis by Atomic Absorption Spectroscopy, Varian Tech-... 

Analysis. Mg is quantitatively determined by colorimetry down to 30 ppb, by atomic absorption spectroscopy (AAS) to 10 ppb, and to 0.1 ppb by electrothermal absorption spectroscopy (ETAS), inductively-coupled plasma emission spectroscopy (ICPES), and inductively-coupled plasma mass spectroscopy (ICPMS). A spot test for Mg which extends to 3 ppm is provided by quinalizarin in alcoholic NaOH. If Mg is present the color is bleached by Br2 water. If not. Be is indicated. 

Heavy metal contamination of pH buffers can be removed by passage of the solutions through a Chelex X-100 column. For example when a solution of 0.02M HEPES containing 0.2M KCl (IL, pH 7.5) alone or with calmodulin, is passed through a column of Chelex X-100 (60g) in the K form the level of Ca ions falls to less than 2 x 10 M as shown by atomic absorption spectroscopy. Such solutions should be stored in polyethylene containers that have been washed with boiling deionised water (5min) and rinced several times with deionised water. TES and Tris have been similarly decontaminated from metal ions (see reference on atomic absorption analysis on p 62). 

A. M. Sofikitis, J. L. Colin, K. V. Desboeufs and R. Losno, Iron analysis in atmospheric water samples by atomic absorption spectroscopy (AAS) in water-methanol. Anal. Bioanal. Chem., 378(2), 2004,... 

The total salt concentration was 0.100 (to.010) N, known to three significant figures. At the high end of the isotherm, the starting solution contained only the ingoing cation at the low end, the solution contained both of the exchanging cations. The equilibrations were carried out for a minimum of three days in a New Brunswick Scientific Company AQUATHERM Water Bath Shaker at 5°, 25°, and 50°C, with temperature control to i0.5°C. Prior to analysis of the equilibrium solutions, the solid and solution phases were rapidly separated by filtration through a Millipore filter immediately after removal from the constant temperature bath. Lead and sodium analyses of the filtrate were obtained by atomic absorption spectroscopy. The cadmium analyses of the filtrate were obtained by plasma emission spectroscopy. These analyses showed that two Na+ ions entered the solution for every Cd2+ or Pb2+ that left ( 2%). 

Forty six field laboratories (mainly from France) have participated in the inter-laboratory comparison. They have analysed the water sample using their regular calibration solution and then have repeated this analysis using the certified standards. They also have analysed the matrix CRM. Laboratories have produced two results (duplicate) per sample. Techniques used were mainly atomic absorption spectroscopy with furnace but also ICP-OES and ICP-MS. 

Water quality projects such as those described below have been shown to be effective methods for engaging students in environmental chemistry courses for majors (Juhl et al. 1997) and for nonscience majors (Lunsford et al. 2007). When the water quality research projects were conducted, Chemistry and the Environment was linked to a world geography course as part of a learning community. Poor water quality and access to potable water were a global environmental theme for both courses. Consequently, the chemistry research projects focused primarily on water analysis. Field water testing kits, atomic absorption spectroscopy, and fluorescence methods (typically for biological con-... 

Atomic Absorption Spectroscopy. A titanium punch was used to cut 2.8-mm-diameter samples from the papers for calcium analysis. A Perkin-Elmer Model AD-2 Electronic Ultramicrobalance was used for the accurate weighing of the paper samples. Calcium content in the Dl-Ca waters and the papers was determined using a Varian Techtron AA-6 Spectrophotometer, with a Model 90 Carbon Rod Atomizer and Potentiometer A-25 Recorder (3). The solid samples (paper samples) were introduced into the graphite cup atomizer with tweezers. The standard solutions and Dl-Ca waters were inserted into the cup atomizer by means of 5-/xL Oxford pipet. 

Analytical methods have been developed which are sensitive enough to measure the low concentration levels of trace metals in seawater. Well defined methods, like emission spectroscopy, neutron activation analysis, anodic stripping voltammetry, atomic absorption spectroscopy, and mass spectroscopy, can be used individually or collectively to obtain the necessary data on trace metal concentrations. So why, even with these well developed methods, are we not getting reliable results from the analysis of trace metals in natural water ... 

Potentiometric stripping analysis, as stated in one review,92 "is not as general an analytical technique for the determination of metal traces as is graphite-furnace atomic absorption spectroscopy." It is used as a complementary technique for assay of some toxic metals in water (zinc, cadmium, lead, and copper in potable water and wastewater,93 94 and lead and thallium in seawater.95 The advantage of anodic stripping voltammetry (ASV) is summarized in two steps, which include electrolytic preconcentration and the stripping process. There are a number of interfering ions that can affect the... 

Control water hyacinths, grown under the same controlled hydroponic conditions, but without platinum added were irradiated under similar conditions. A large photopeak at 158 keV resulted, whereas the 208 keV peak was not visible. Thus some interfering nuclide with a photopeak around 158 keV is present even in the control material. The interfering elements are under further investigation. This interference seems to be present both in animal and in plant tissue. LeRoy (16) has compared the results of the analysis of canine heart, liver and muscle by both electrothermal atomisation atomic absorption spectroscopy (ETA AAS) and INAA. It was found that the results for Pt using INAA... 

Emission Spectroscopy was carried out for obtaining of preliminary information for metals content. This semi-quantitative analysis showed that the water from comparatively clean area contains only Mg, Ca, Si, and Fe, while the water from industrial area contains Mn besides Mg, Ca, Si, and Fe. The quantitative determination of Mg, Ca, Mn, and Fe was made by Atomic Absorption Spectroscopy and the quantitative determination of Si was made by UV-spectroscopy. Fig.6 illustrates the metal content of the water samples from the comparatively clean area and the industrial area. It shows that the metal content in the water from the industrial area is higher in contrast with this in the water from the comparatively clean area. The quantities of Mg and Ca are vastly great than those of Si, Fe, and Mn. As a whole metal content in the aquatic systems is low and there is no presence of heavy metals. 

A number of instrumental methods have been used to determine ppb levels of cobalt in water (4,5,6), biological tissues (7,8), and air particulates (9, 10). Kinetic methods are capable of measuring sub-parts-per-billion (11,12). Potentially any of these techniques could be used in the analysis of petroleum, but only neutron activation analysis (I, 3) and atomic absorption spectroscopy (13,14) have been applied to any appreciable extent. Flame and heated vaporization atomic absorption techniques were selected for more detailed study by the Project because atomic absorption is sensitive, subject to relatively few interferences, and is rather generally available. 

Even with the diflBculties cited above, the combination of flame emission and atomic absorption spectroscopy has become in a very short time one of our better methods for the analysis of waters for cations for the following reasons limited sample preparations necessary, high sensitivity, good analytical precision, low cost, and simphcity of equipment. 

The application of stripping voltammetry includes the measurements of metal ions and organic compounds in a variety of chemical, environmental, metallurgical, geological, biological, biochemical, pharmaceutical, and clinical materials [2, 121-123]. They are used in routine trace metal analysis of waters [124] and can serve as reliable, sensitive, and precise methods for the verification of results obtained by atomic absorption spectroscopy, or some chromatographic techniques [125]. 

Several authors have used ion-exchange methods to preconcentrate trace metals for further analysis from geothermal water 410) for x-ray determination 411, 412) for y-spectroscopy (475) and for atomic absorption spectroscopy (474, 475). For x-ray analysis, an attractive method for preconcentration is the use of ion-exchange resin-loaded paper (476-422). Although these methods often need slow filtration of the sample or several passes to obtain quantitative extraction of the metals, the sorbed material is presented in a convenient form for X ray, and low-concentration solutions and large sample volumes can be used. 

Silicones have been extracted from environmental samples with solvents such as hexane, diethyl ether, methyl isobutylketone, ethyl acetate, and THF, using either sequential or Soxhlet techniques (690-695). Silicones of a wide range of molecular weights and polarities are soluble in THF. This feature, coupled with its volatility and miscibility with water, makes THF an excellent solvent for the extraction of silicones from wet samples, ie, soils and sediments. Trace levels of silicones extracted from environmental samples have been measured by a number of techniques, including atomic absorption spectroscopy (AA), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), pyrolysis GC-MS, as well as H and Si NMR spectroscopy (674,684,692,696-700). The use of separation techniques, such as gel permeation and high pressure liquid chromatography interfaced with sensitive, silicon-specific AA or ICP detectors, has been particularly advantageous for the analysis of silicones in environmental extracts (685,701-704). 

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