Absorption spectrometry phase

COMPARISON OF MICROWAVE ASSISTED EXTRACTION METHODS FOR THE DETERMINATION OF PLATINUM GROUP ELEMENTS IN SOIL SAMPLES BY ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY AFTER PHASE SEPARATION-EXTRACTION... 

Figure 15-12 is a schematic illustration of a technique known as acid volatile sulfides/ simultaneously extracted metals analysis (AVS/SEM). Briefly, a strong acid is added to a sediment sample to release the sediment-associated sulfides, acid volatile sulfides, which are analyzed by a cold-acid purge-and-trap technique (e.g., Allen et ai, 1993). The assumption shown in Fig. 15-12 is that the sulfides are present in the sediments in the form of either FeS or MeS (a metal sulfide). In a parallel analysis, metals simultaneously released with the sulfides (the simultaneously extracted metals) are also quantified, for example, by graphite furnace atomic absorption spectrometry. Metals released during the acid attack are considered to be associated with the phases operationally defined as "exchangeable," "carbonate," "Fe and Mn oxides," "FeS," and "MeS."... 

As in the 1,2-dichloroethane case too, transient EMF and SHG responses to KSCN were observed for the nitrobenzene membranes without ionic sites. This suggests that here too not only SCN but also K ions are transferred into the nitrobenzene phase. Salt extraction into the bulk of the organic phase, in analogy to similar observations previously reported for neutral ionophore-incorporated liquid membranes without ionic sites [55], was indeed independently confirmed by atomic absorption spectrometry. Figure 15 shows the concentration of K in nitrobenzene equilibrated at room temperature with a 10 M aqueous solution of KSCN as a function of equilibration time. The presence of the ion exchanger TDDMA-SCN efficiently suppresses KSCN extraction into the organic phase but in its absence a substantial amount of KSCN enters the nitrobenzene phase. The trends of the EMF and the SHG responses are therefore very similar in spite of the different polarities of the plasticizers. 

Amoli, H. S. and Simpson, P. Development of an ion chromatography-solid phase extraction atomic absorption spectrometry method for the determination of low level ions in aqueous phase, Biomed. Chromatogr., 12, 304, 1998. 

Statham [448] has optimised a procedure based on chelation with ammonium dithiocarbamate and diethylammonium diethyldithiocarbamate for the preconcentration and separation of dissolved manganese from seawater prior to determination by graphite furnace atomic absorption spectrometry. Freon TF was chosen as solvent because it appears to be much less toxic than other commonly used chlorinated solvents, it is virtually odourless, has a very low solubility in seawater, gives a rapid and complete phase separation, and is readily purified. The concentrations of analyte in the back-extracts are determined by graphite furnace atomic absorption spectrometry. This procedure concentrates the trace metals in the seawater by a factor of 67.3. 

Fitzgerald et al. [477] have described a method based on cold-trap preconcentration prior to gas-phase atomic absorption spectrometry for the determination of mercury down to 2 ng/1 in seawater. 

Rampon and Cavelier [523] used atomic absorption spectrometry to determine down to 0.5 xg/l nickel in seawater. Nickel is extracted into chloroform from seawater (500 ml) at pH 9-10, as its dimethylglyoxime complex. Several extractions and a final washing of the aqueous phase with carbon tetrachloride... 

Armannsson [659] has described a procedure involving dithizone extraction and flame atomic absorption spectrometry for the determination of cadmium, zinc, lead, copper, nickel, cobalt, and silver in seawater. In this procedure 500 ml of seawater taken in a plastic container is exposed to a 1000 W mercury arc lamp for 5-15 h to break down metal organic complexes. The solution is adjusted to pH 8, and 10 ml of 0.2% dithizone in chloroform added. The 10 ml of chloroform is run off and after adjustment to pH 9.5 the aqueous phase is extracted with a further 10 ml of dithizone. The combined extracts are washed with 50 ml of dilute ammonia. To the organic phases is added 50 ml of 0.2 M-hydrochloric acid. The phases are separated and the aqueous portion washed with 5 ml of chloroform. The aqueous portion is evaporated to dryness and the residue dissolved in 5 ml of 2 M hydrochloric acid (solution A). Perchloric acid (3 ml) is added to the organic portion, evaporated to dryness, and a further 2 ml of 60% perchloric acid added to ensure that all organic matter has been... 

Cadmium, copper, and silver have been determined by an ammonium pyrrolidine dithiocarbamate chelation, followed by a methyl isobutyl ketone extraction of the metal chelate from the aqueous phase [677], and finally followed by graphite furnace atomic absorption spectrometry. The detection limits of this technique for 1% absorption were 0.03 pmol/1 (copper), 2 nmol/1 (cadmium), and 2 nmol/1 (silver). 

Hayase et al. [684] first extracted the seawater sample with chloroform to remove dissolved organic matter prior to analysis of the aqueous phase by graphite furnace atomic absorption spectrometry. Seawater samples at pH 3 and at pH 8 were extracted with chloroform, evaporated to dryness, and the residue treated with nitric acid. Acid solutions were subjected to metal analyses by graphite furnace atomic absorption spectrometry. 

Lei et al. reported a method for the indirect determination of trace amounts of procaine in human serum by atomic absorption spectrophotometry [54], The sample was mixed with HCIO4, heated at 85°C for 30 minutes, diluted to a known volume with water, and centrifuged. 1 mL of the supernatant solution was buffered with 0.1 M sodium acetate-acetic acid to pH 3.86, and mixed with 0.2 M Zn(SCN)j reagent to a final concentration of 0.1 M. After dilution to 50 mL with water, the solution was shaken for 1 minute with 10 mL of 1,2-dichloroethane, whereupon the zinc extracted into the organic phase was determined by air-acetylene flame atomic absorption spectrometry for the indirect determination of procaine. The detection limit was found to be 0.1 pg/g, with a recovery of 89-98% and a coefficient of variation (n = 10) equal to 3.2%. 

Hydride generation for analytical use was introduced at the end of the 1960s using arsine formation (Marshal Reaction) in flame atomic absorption spectrometry (FAAS). A simple experimental setup for a hydride generator is shown in Figure 5.18. Today, hydride generation,91,92 which is the most widely utilized gas phase sample introduction system in ICP-MS, has been developed into... 

A. F. Barbosa, M. G. Segatelli, A. C. Pereira, A. De Santana Santos, L. T. Kubota, P. O. Luccas and C. R. T. Tarley, Solid-phase extraction system for Pb(n) ions enrichment based on multiwall carbon nanotubes coupled on-line to flame atomic absorption spectrometry, Talanta, 71(4), 2007, 1512-1519. 

B. Do, S. Robinet, D. Pradeau and F. Guyon, Speciation of arsenic and selenium compounds by ion-pair reversed-phase chromatography with electrothermal atomic absorption spectrometry. Application of experimental design for chromatographic optimisation, J. Chromatogr. A, 918(1), 2001, 87-98. 

An early method for the determination of arsenic in soils is that of Forehand et al. [23]. This method is based on the selective extraction of arsenic(III) by benzene and analysis of the extract by atomic absorption spectrometry. Firstly the soil is allowed to stand with 9.9 M hydrochloric acid for 12 hours, and then the arsenic is reduced from arsenic(V) to arsenic(III) with stannous chloride and potassium iodide. Following adjustment to pH 9 with hydrochloric acid, the aqueous phase is extracted with benzene. The benzene extract is then treated with water and the water extract analysed by atomic absorption spectrometry at 193.7 nm. An average recovery of 88% of the arsenic present in sandy soils was achieved by this procedure. 

Azzaria and Aftabi [ 149] showed that stepwise (as compared to continuous) heating of soil samples before determination of mercury by atomic absorption spectrometry gives increased resolution of the different phases of mercury. A gold-coated graphite furnace atomic absorption spectrometer has been used to determine mercury in soils [150]. 

Tawali, A.B. and Schwedt, G. (1997) Combination of solid phase extraction and flame atomic absorption spectrometry (FAAS) for differentiated analyses of labile iron (II) and iron (III) species. Fresenius J. Anal. Chern., 357, 50-55. 

Jiang, H., Y. Qin, and B. Hu. 2008. Dispersive liquid phase microextraction (DLPME) combined with graphite furnace atomic absorption spectrometry (GFAAS) for determination of trace Co and Ni in environmental water and rice samples. Talanta 74 1160-1165. 

Latif, E., A.K. Aslihan, and S. Mustafa. 2008. Solid phase extraction method for the determination of iron, lead and chromium by atomic absorption spectrometry using Amberite. J. Hazard. Mater. 153 454-461. 

Anthemidis, A.N. and K.-I.G. Ioannou. 2006. Evaluation of polychlorotrifluoroethylene as sorbent material for on-line solid phase extraction systems Determination of copper and lead by flame atomic absorption spectrometry in water samples. Anal. Chim. Acta 575 126-132. 

Soylak, M., L. Elci, and M. Dogan. 2003. Uses of activated carbon columns for solid phase extraction studies prior to determinations of traces heavy metal ions by flame atomic absorption spectrometry. Asian J. Chem. 15 1735-1738. 

To assess the viability of the copper-chloride cycle, a dedicated experimental programme is proposed the study of the occurrence of possible side reactions. In order not to change the speciation of the vapour phase, the use of optical absorption spectrometry is proposed UV visible spectrometry to detect the possible presence of molecular chlorine, product of side reactions. 

In the case that an organic phase contains light absorbing compounds, an external reflection (ER) absorption spectrometry is more useful than a TIR spectrometry [30,31]. Another advantage of the ER method is its higher sensitivity than the TIR method, especially as using s-polarized light. Therefore, it can be used as a universal absorption spectrometry of adsorbed species. Typical optical cells used for the TIR spectrometry and ER absorption spectrometry are shown in Fig. 3. 

M. A. Zezzi Arruda, M. Gallego, M. Valcarcel, Determination of aluminium in slurry and liquid phase by flow injection analysis graphite furnace atomic absorption spectrometry, Anal. Chem., 85 (1997), 3331-3335. 

S. Fragueiro, I. Lavilla, C. Bendicho, Direct coupling of solid phase microextraction and quartz tube-atomic absorption spectrometry for selective and sensitive determination of methylmercury in seafood an assessment of chloride and hydride generation, J. Anal. Atom. Spectrom., 19 (2004), 250-254. 

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