Contents 1 Absorption Spectrophotometry

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. 

Atomic absorption spectrophotometry Flame Flameless Simple, versatile measures total metal content. Knowledge of interfering effects important. 10 = to 10 M 10 to 10 M... 

Hernandez, O. M., Fraga, J. M. G., Jimenez, A. 1., Jimenz, F., and Arias, J. J. (2005). Characterization of honey from the Canary Islands Determination of the mineral content by atomic absorption spectrophotometry. Food Chem. 93,449 58. 

Urine, feces and food were analyzed for calcium content by atomic absorption spectrophotometry. Data were subjected to statistical analysis by analysis of variance and Duncan s Multiple Range Test. 

Pellenberg [114] analysed soils and river sediment for silicone content by nitrous oxide-acetylene flame atomic absorption spectrophotometry. He showed that total carbon and total carbohydrates both correlate well with silicone content and the correlation between sedimentary silicone and presumed sewage material is good enough to suggest silicone as a totally synthetic, specific tracer for sewage in the aquatic environment. 

Potassium. Quality standards for bottled wines now require a high degree of clarity. Even slight precipitates of potassium acid tartrate are considered detrimental. Whether wines are stabilized by cold treatment, long aging, or ion exchange, determination of their potassium content may be necessary. Precipitation as the acid tartrate (6) is widely used. However, precipitation as potassium tetraphenylborate is used in Europe (4, 22). Flame photometry and atomic absorption spectrophotometry are... 

Precipitation experiments Mucci and Morse (1984) reported solubility data for several magnesian calcites produced from precipitation experiments (see Figures 3.7 and 3.14). In their experiments overgrowths of magnesian calcite were precipitated on calcite seeds in a pH-stat which maintained constant solution composition. The overgrowth compositions were determined by atomic absorption spectrophotometry and X-ray diffraction. The Mg contents of the overgrowths varied only with the Mg Ca ratio in solution, and the overgrowths were shown to be... 

According to the British Pharmacopoeia 2002 [2] and Indian Pharmacopoeia [6], mefenamic acid in capsule and tablet preparations are identified by examination using infrared absorption spectrophotometry as the following procedure. Extract a quantity of the capsule contents (or powdered tablets) containing 0.25 g of mefenamic acid with two 30 mL quantities of ether. Wash the combined extracts with water, evaporate to dryness on a water bath, and dry the residue at 105°C. Dissolve a sufficient quantity in the minimum volume of absolute ethanol, and evaporate to dryness on a water bath. The infrared absorption spectrum is concordant with the reference spectrum of mefenamic acid. 

According to the Pharmacopoeia of the People s Republic of China [7], the method of identification testing of mefenamic acid in capsule and tablet preparations is based on light absorption spectrophotometry. A specific quantity of the powdered contents of capsules (or powdered tablets), equivalent to 0.25 g mefenamic acid, is dissolved in a mixture of 10 mL of 0.1 mL/L hydrochloric acid/methanol (1 99), shaken, and filtered. Then some quantity of the filtrate is diluted with the above-mixed solution to produce a solution having a concentration of about 20 pg/mL. The absorption spectrum of the solution exhibits maxima at 279 nm and 350 nm. 

Khalil et al. [51] described the microquantitative determination of mefenamic acid based on the reaction of mefenamic acid with a silver nitrate solution in a neutral alcoholic medium. The formed precipitation is quantitatively determined directly or indirectly through the silver content of the precipitation formed or the residual unreacted silver ions in the filtrate by atomic absorption spectrophotometry. The results obtained in both the procedures either in their pure form or in their pharmaceutical formulations are accurate and precise. The stoichiometric relationship of the reaction was studied using lob s continuous variation method, and it was found to be (1 1) drug Ag+ for the mefenamic acid. 

Meranger, J.C., and E. Somers. 1968. Determination of the heavy metal content of seafoods by atomic absorption spectrophotometry. Bull. Environ. Contamination Toxicol. 3 360-365. 

Subjects were not allowed to eat or drink anything else during the test period. Samples of plasma were collected after a 12-hour fast and hourly for 4 hours postdose. Plasma samples were analyzed for manganese content using graphite furnace atomic absorption spectrophotometry (Friedman, et al., J. Hutr. In press.) Consecutive tests in the same subjects were separated by a minimum of 14 days, since preliminary testing indicated no residual effect of the manganese dose after this time interval. 

Zinc content of urine, feces and food were determined by atomic absorption spectrophotometry. 

The total zinc content was determined by atomic absorption spectrophotometry (Perkin Elmer Model 360), after dry-ashing at 500°C. The calcium analysis was also done by atomic absorption spectrophotometry, but after wet-ashing in sulphuric acid and hydrogen peroxide. 

Spectrofluorimetry differs from absorption spectrophotometry in not yielding an absolute scale of values. For this reason it is essential to employ a reference standard for quantitative measurements. For example, some pharmacopoeial tests, such as the test for uniformity of content for digitoxin tablets, employ a spectrofluorimefric assay and comparison wi an ofticial reference standard. Quantitative Spectrofluorimetry has been proposed for a munber of naturally fluorescent compoimds, including ergometrine, riboflavine, tiie catechol-amines, phenothiazines, the barbiturates (at pH 13), and certain antibiotics such as chlortetracycline and oxytetracycline. 

Sample analysis by thermal ionization mass spectrometry (TIMS) results in measurement of isotopic ratios of minerals. Total mineral content of samples is then determined by one of two methods. One approach is to use flame atomic absorption spectrophotometry (AAS) to determine total mineral content of samples. Since AAS does not have the same level of precision as TIMS a sufficient number of replicates is analyzed for a mineral content determination with a CV of within 1%. Alternatively if a mineral has 3 or more isotopes and fractionation corrections are not made the following procedure may be used. An individual is fed one isotope and another isotope is added to the sample prior to analysis to determine the total mineral content of the sample by dilution of the second isotope. In this way both the amount of the isotope fed which is recovered in the feces and the total mineral content of the sample can be determined simultaneously. If fractionation corrections are to be made a mineral must have at least four isotopes. Details of these procedures will be reported separately. 

The instrumentation for atomic absorption spectrophotometry is very well-defined and can range from a relatively simple manually operated instrument to a completely automated system that is on line to a central database. In addition, accurate results can be obtained on a wide range of samples. The future lies in using this technique to solve problems rather than to further develop instrumentation. For example, the FDA published new guidelines for the aluminum content of products used in total parenteral nutrition. 

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. 

B. Determination of Lipid concentration in ARSL The arsono-lipid content of arsonoliposomes is determined by atomic absorption spectrophotometry after digestion with concentrated nitric acid, as previously reported (22). In brief, 20 pL from each (ARSL) suspension are digested with 2 mL of nitric acid, in a 25 mL conical flask. The flask is heated on a hot plate placed under a hood, by slowly increasing the temperature to 90-100°C. The solution is allowed to evaporate to dryness (but not charred), and the residue is taken up with 3 mL HNO3 and 3 mL cold (4°C) 30% H O. A reaction is then initiated by slowly heating the mixture and the rate of decomposition of is controlled by frequently removing the flask from the hot plate. The solution is then brought to a brief boil, cooled, and diluted to 50.0 mL with d.d. H O. 

F, lignin 5 minutes), boiling Cl hr. in a boiling water bath), and incubation for 2h hours at 30°C which served as the control. Samples were filtered and the residue together with the filter paper was digested with concentrated HC1 for 10 minutes, then cooled and filtered. The filtrates were analyzed via atomic absorption spectrophotometry (AAS)for soluble metal content. 

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