Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Atomic absorption spectrophotometry, for

The vanadium eluate was slowly evaporated under an infrared lamp, the residue dissolved in 6 M hydrochloric acid (10 ml) containing 1 ml of the aluminium chloride solution [603], and vanadium was determined by atomic absorption spectrophotometry. For calibration, suitable standard solutions were aspirated before and after each batch of samples. [Pg.232]

Tin can be measured readily at trace concentrations in aqueous solutions by flame or furnace atomic absorption spectrophotometry. For flame AA measurement, air-acetylene flame is suitable. The metal can be identified accurately at 224.6 nm. Tin also can be measured by other instrumental techniques such as ICP-AES, ICP/MS and neutron activation analysis. [Pg.937]

The exploitation of atomic-absorption spectrophotometry for monitoring HPLC column effluents has been recently examined by Funasaka et al. [46]. An eluent-vaporizing system was designed which introduced the effluent into the atomic-absorption unit. The limit of detection of compounds such as ethylmercury chloride was ca. 10 ng compared to 30 jug for a UV detector at 210 nm. The extreme selectivity of atomic absorption could make this technique of great value for the analysis of trace amounts of organometallic compounds and metal chelates. [Pg.104]

Table 1 shows the detection limits of atomic absorption spectrophotometry for various metals. In general, flame atomic absorption spectrophotometry is quantitative in the lower parts-per-million levels and is readily automated for routine, high-volume samples. The other three techniques are used primarily for trace analysis and are quantitative to the lower parts-per-million levels for many elements. [Pg.3368]

After transport to a laboratory, gases are introduced into an analytical instrument for quantitative determination of the constituents of interest. Soil air in a container is introduced directly to the instmment, whilst adsorbed gas is released by thermal of chemical desorption. The instrumental methods most widely used for gas analyses include gas chromatography, mass spectrometry and atomic absorption spectrophotometry. For quantifying the radiation scars on film, image analysis methods are employed. [Pg.14]

The Element.—Analytical methods for the determination of trace quantities of selenium in two very different materials have been described. The first275 employs the use of flameless atomic absorption spectrophotometry for the direct determination of selenium (and Pb, Bi, Se, Te, and Tl) at p.p.m. levels in high-temperature alloys. The second method276 is able to determine the selenium content of plant material at levels as low as 0.005 fxg g The method involves the reaction of SeIV with 4-nitro-o-phenylenediamine to form 5-nitropiaselenol, which may be detected by means of a gas chromatograph. [Pg.451]

Dang TMN, Tran QT and Vu KV (1999) Determination of arsenic in urine by atomic absorption spectrophotometry for biological monitoring of occupational exposure to arsenic. Toxicol Lett 108 179-183. [Pg.1356]

Williams AI (1972) The use of atomic absorption spectrophotometry for the determination of copper, chromium and arsenic in preserved wood. Analyst 97 104-110. [Pg.631]

Provide an SOP for the determination of cadmium in lake sediments by atomic absorption spectrophotometry using a normal calibration curve. [Pg.707]

Determination of gold concentrations to ca 1 ppm in solution via atomic absorption spectrophotometry (62) has become an increasingly popular technique because it is available in most modem analytical laboratories and because it obviates extensive sample preparation. A more sensitive method for gold analysis is neutron activation, which permits accurate determination to levels < 1 ppb (63). The sensitivity arises from the high neutron-capture cross section (9.9 x 10 = 99 barns) of the only natural isotope, Au. The resulting isotope, Au, decays by P and y emission with a half-life of 2.7 d. [Pg.381]

Concurrent with requirements for low levels of mercurials in discharge water is the problem of their deterrnination. The older methods of wet chemistry are inadequate, and total rehance is placed on instmmental methods. The most popular is atomic absorption spectrophotometry, which rehes on the absorption of light by mercury vapor (4). Solutions of mercury compounds not stabilized with an excess of acid tend to hydrolyze to form yeUow-to-orange basic hydrates. These frequendy absorb onto the walls of containers and may interfere with analytical results when low levels (ppm) of mercury are determined. [Pg.112]

Potassium is analyzed in chemicals that are used in the fertilizer industry and in finished fertilizers by flame photometric methods (44) or volumetric sodium tertraphenylboron methods (45) as approved by the AO AC. Gravimetric deterrnination of potassium as K2PtClg, known as the Lindo-Gladding method (46), and the wet-digestion deterrnination of potassium (47) have been declared surplus methods by the AO AC. Other methods used for control purposes and special analyses include atomic absorption spectrophotometry, inductively coupled plasma (icp) emission spectrophotometry, and a radiometric method based on measuring the radioactivity of the minute amount of the isotope present in all potassium compounds (48). [Pg.536]

Spectrophotometric deterrnination at 550 nm is relatively insensitive and is useful for the deterrnination of vitamin B 2 in high potency products such as premixes. Thin-layer chromatography and open-column chromatography have been appHed to both the direct assay of cobalamins and to the fractionation and removal of interfering substances from sample extracts prior to microbiological or radioassay. Atomic absorption spectrophotometry of cobalt has been proposed for the deterrnination of vitamin B 2 in dry feeds. Chemical methods based on the estimation of cyanide or the presence of 5,6-dimethylben2irnida2ole in the vitamin B 2 molecule have not been widely used. [Pg.115]

Alkaline-earth metals are often deterruined volumetricaHy by complexometric titration at pH 10, using Eriochrome Black T as indicator. The most suitable complexing titrant for barium ion is a solution of diethylenetriaminepentaacetic acid (DTPA). Other alkaline earths, if present, are simultaneously titrated, and in the favored analytical procedure calcium and strontium are deterruined separately by atomic absorption spectrophotometry, and their values subtracted from the total to obtain the barium value. [Pg.484]

BeryUium aUoys ate usuaUy analyzed by optical emission or atomic absorption spectrophotometry. Low voltage spark emission spectrometry is used for the analysis of most copper-beryUium aUoys. Spectral interferences, other inter-element effects, metaUurgical effects, and sample inhomogeneity can degrade accuracy and precision and must be considered when constmcting a method (17). [Pg.68]

Metal Extraction. As with other carboxyhc acids, neodecanoic acid can be used in the solvent extraction of metal ions from aqueous solutions. Recent appHcations include the extraction of zinc from river water for deterrnination by atomic absorption spectrophotometry (105), the coextraction of metals such as nickel, cobalt, and copper with iron (106), and the recovery of copper from ammoniacal leaching solutions (107). [Pg.106]

Metal Content. Two common analytical methods for determining metal content are by titration and by atomic absorption spectrophotometry (aas). The titration method is a complexiometric procedure utilizing the disodium salts of ethylenediaminetetraacetic acid (EDTA). The solvent, indicator. [Pg.219]

Further techniques which may be applied directly to the solvent extract are flame spectrophotometry and atomic absorption spectrophotometry (AAS).13 The direct use of the solvent extract in AAS may be advantageous since the presence of the organic solvent generally enhances the sensitivity of the method. However, the two main reasons for including a chemical separation in the preparation of a sample for AAS are ... [Pg.174]

Theory. Conventional anion and cation exchange resins appear to be of limited use for concentrating trace metals from saline solutions such as sea water. The introduction of chelating resins, particularly those based on iminodiacetic acid, makes it possible to concentrate trace metals from brine solutions and separate them from the major components of the solution. Thus the elements cadmium, copper, cobalt, nickel and zinc are selectively retained by the resin Chelex-100 and can be recovered subsequently for determination by atomic absorption spectrophotometry.45 To enhance the sensitivity of the AAS procedure the eluate is evaporated to dryness and the residue dissolved in 90 per cent aqueous acetone. The use of the chelating resin offers the advantage over concentration by solvent extraction that, in principle, there is no limit to the volume of sample which can be used. [Pg.212]

Evenson, M. A. and Anderson, C. T., Jr. Ultramlcro Analysis for Copper, Cadmium and Zinc In Human Liver Tissue by Use of Atomic Absorption Spectrophotometry and the Heated Graphite Tube Atomizer". Clin. Chem. (1975), 2, 537-543. [Pg.265]

J. "Determination of Copper In Serum With a Graphite Rod Atomizer for Atomic Absorption Spectrophotometry". Anal. Chlm. Acta (1971), 263-269. [Pg.265]

Kubaslk, N. P., Volosln, M. T., and Murray, M. H. "A Quantitative Micro Technique for the Analysis of Lead In Blood by Carbon Rod Atomization and Atomic Absorption Spectrophotometry . Clin. Blochem. (1972), 5, 266-270. [Pg.267]

Yeh, Y-Y., and Zee, P. Mlcromethod for Determining Total Iron-Binding Capacity by Flameless Atomic Absorption Spectrophotometry". Clin. Chem. (1974), 20, 360-364. [Pg.270]

The technique that has been widely apphed for analyzing total merctrry in aqttatic biota since the late 1960s (cold vapor atomic absorption spectrophotometry) lemains a vahd analytical method. Accordingly, we irtfer that most of the historical data for total merctrry in fish tissues are vahd. Moreover, the historical data on total merctrry concentrations in fish tissues provide defettsible estimates of prior MeHg concentrations. [Pg.106]

A method has been developed for differentiating hexavalent from trivalent chromium [33]. The metal is electrodeposited with mercury on pyrolytic graphite-coated tubular furnaces in the temperature range 1000-3000 °C, using a flow-through assembly. Both the hexa- and trivalent forms are deposited as the metal at pH 4.7 and a potential at -1.8 V against the standard calomel electrode, while at pH 4.7, but at -0.3 V, the hexavalent form is selectively reduced to the trivalent form and accumulated by adsorption. This method was applied to the analysis of chromium species in samples of different salinity, in conjunction with atomic absorption spectrophotometry. The limit of detection was 0.05 xg/l chromium and relative standard deviation from replicate measurements of 0.4 xg chromium (VI) was 13%. Matrix interference was largely overcome in this procedure. [Pg.67]

Figure 5.3. Zinc reactor column for generation of arsine by electrothermal atomic absorption spectrophotometry. Source Author s own files... [Pg.139]

Electrothermal atomic absorption spectrophotometry with Zeeman background correction was used by Zhang et al. [141] for the determination of cadmium in seawater. Citric acid was used as an organic matrix modifier and was found to be more effective than EDTA or ascorbic acid. The organic matrix modifier reduced the interferences from salts and other trace metals and gave a linear calibration curve for cadmium at concentrations < 1.6 pg/1. The method has a limit of detection of 0.019 pg/1 of cadmium and recoveries of 95-105% at the 0.2 pg of cadmium level. [Pg.151]

Klinkhammer [432] has described a method for determining manganese in a seawater matrix at concentrations ranging from about 30 to 5500 ng/1. The samples are extracted with 4 nmol/1 8-hydroxyquinoline in chloroform, and the manganese in the organic phase is then back-extracted into 3 M nitric acid. The manganese concentrations are determined by graphite furnace atomic absorption spectrophotometry. The blank of the method is about 3.0 ng/1, and the precision from duplicate analyses is 9% (1 SD). [Pg.196]

When the samples were returned to the laboratory the pH was adjusted to approximately pH 8 using concentrated ammonia (Ultrapure, G. Frederick Smith). Chelating cation exchange resin in the ammonia form (20 ml Chelex 100,100 - 200 mesh, Bio-Rad) was added to the samples and they were batch extracted on a shaker table for 36 hours. The resin was decanted into columns, and the manganese eluted using 2N nitric acid [129]. The eluant was then analysed by graphite furnace atomic absorption spectrophotometry. Replicate analyses of samples indicate a precision of about 5%. [Pg.196]


See other pages where Atomic absorption spectrophotometry, for is mentioned: [Pg.134]    [Pg.245]    [Pg.249]    [Pg.544]    [Pg.177]    [Pg.315]    [Pg.486]    [Pg.181]    [Pg.134]    [Pg.245]    [Pg.249]    [Pg.544]    [Pg.177]    [Pg.315]    [Pg.486]    [Pg.181]    [Pg.4]    [Pg.48]    [Pg.224]    [Pg.685]    [Pg.707]    [Pg.28]    [Pg.58]    [Pg.276]    [Pg.88]    [Pg.464]    [Pg.259]   


SEARCH



Absorption spectrophotometry

Spectrophotometry, atomic

© 2024 chempedia.info