Calcium atomic absorption spectrophotometry

Quigley, M. N. Determination of Calcium in Analgesic Tablets Using Atomic Absorption Spectrophotometry, ... 

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. 

Atomic absorption spectrophotometry [165,166] has been used in the determination of calcium and magnesium in seawater. 

Phytate analysis of muffins, diet composites and stools was performed by a modification of the ferric ion precipitation method for HS-I (5) and by an ion exchange method for HS-II and -III (6). Calcium was determined by atomic absorption spectrophotometry. 

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. 

Procedure (determination). Magnesium is determined by atomic absorption spectrophotometry (see Method 5.2, Measurement of calcium and magnesium by AAS ). 

Complexometric titration with EDTA is the usual winery procedure for determining calcium (4, 6, 22, 113), but atomic absorption spectrophotometry (51,53,112) and flame photometry and a rapid micro method based on oxalate precipitation (114) have been used successfully. 

Analyze the metals, calcium, and magnesium in the sample using atomic absorption spectrophotometry or any other suitable technique and determine their concentrations. 

Bano FJ. 1973. The determination of trace amounts of barium in calcium carbonate by atomic-absorption spectrophotometry. Analyst 98 655-658. 

M. C. Yebra Biurrun, M. L. Mella Louzao, A. Bermejo Barrera, M. P. Bermejo Barrera, Comparative study of the determination of calcium in different types of milk by atomic absorption spectrophotometry after different sample treatments, Alimentaria, 28 (1991), 23-25. 

Calcium in Raw and Potable Waters by Atomic Absorption Spectrophotometry, HMSO, London, 1977. 

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. 

Flow Dialysis - Dialysis tubing is boiled in 5% NaHCOj and then in deionized water. Buffer, 10 mM HEPES-KOH, 100 mM KQ, pH 7.5, is treated for the removal of contaminating calcium by Chelex chromatography (Biorad Laboratories). EDTA is removed from protein samples by passage over two Sephadex G-25 PD-10 columns. Calcium is removed from protein samples dialyzed against HEPES-KQ buffer by Chelex chromatography just prior to flow dialysis. The concentration of calcium is determined in all solutions by atomic absorption spectrophotometry. 

D3. David, D. J., Determination of calcium in plant material by atomic-absorption spectrophotometry. Analyst 84, 536-545 (1959). 

Slavin, W., Sprague, S., and Manning, D. C., The determination of calcium by atomic absorption spectrophotometry. Atomic Absorption Newsletter No. 15. Perkin-Elmer Corp., Norwalk, Conn. (September 1963). 

Z3. Zettner, A., and Seligson, D., Application of atomic absorption spectrophotometry in the determination of calcium in serum. Clin. Chem. 10, 869-890 (19M). 

The concentration of sodium ions was determined by flame photometry. Analysis of nickel, calcium, and magnesium ion concentration was carried out by atomic absorption spectrophotometry (Pye Unicam 8800, United Kingdom). The concentration of sulfate ions was determined by titration with barium chloride (BaCl2) solution in the presence of rhodizonate as indicator. Chloride ions were determined using ion-selective electrodes (manufacmred by Radelkis, Hungary). 

Sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca), concentrations were measured by atomic absorption spectrophotometry (Perkin Elmer 2380 equipped with deuterium background corrector). Cd, Zr, and Cu concentrations were obtained in a quartz cell, by differential pulse anodic stripping voltammetry (DPASV) with a assy carbon thin-film mercury covered electrode (Tacussel polarographic equipment fitted with a Tacussel EDI type electrode). Pure water was produced by a Milli. Q water purification system (Millipore). Chlorate, sulfate and carbonate were measured using classical methods. 

Many methods have been used historically to measure total Today, only photometric, ISE, and occasionally atomic absorption spectrophotometry methods are routinely used by clinical laboratories for the measurement of serum and urine total calcium. According to the College of American Pathologists Comprehensive Chemistry Survey,... 

Total calcium is most frequently measured by spectrophotometry using metaUochromic indicators or dyes. Of the metaUochromic indicators that change color on selectively binding calcium, o-cresolphthalein complexone (CPC) (3, 3"-bis [ [bis-(carboxymethyl)amino] -methyl] -5", 5"-dimethylphenolphthalein) (Figure 49-3) and arsenazo III are most widely used. These methods, although less accurate and reproducible than atomic absorption spectrophotometry, have been easier to automate on chemistry analyzers. 

Atomic Absorption Spectrometry Methods The National Committee for Clinical Laboratory Standards (NCCLS) has approved a method using atomic absorption spectrophotometry (AAS) as a reference method for measuring total serum calcium. This method has been compared with isotope dilution-mass spectrometry (ID-MS), the definitive method for total serum calcium developed by the National Institute of Standards and Technology. The reference method is reported to have an accuracy of 100 2%, compared with 100 0.2% for ID-MS. Although AAS can provide better accuracy and precision for total serum calcium than the widely used photometric methods, it is used by only a few laboratories. It should continue to be used for validating new total calcium methods. 

Pybus J, Feldman FJ, Bowers GN Jr. Measurement of total calcium in serum by atomic absorption spectrophotometry with use of a strontium internal reference. Clin Chem 1970 16 998-1007. 

Welch MW, Hamar DW, Fettman MJ. Method comparison for calcium determination by flame atomic absorption spectrophotometry in presence of phosphate. Clin Chem 1990 36 351-54. 

However, sodium may be determined also by atomic absorption spectrophotometry using emission mode. Calcium does not normally interfere in this technique. 

Where atomic absorption spectrophotometry is possible the ammonium acetate extract can be directly analysed for Ca and Mg. The spectrophotometric standards are prepared in the ammonium acetate solution and both the standard and extracts are read against ammonium acetate as blank. If AAS is not possible the calcium and magnesium are analysed by complexometric titrations using ethylene diamine tetra acetic acid (EDTA). 

A.M.R. Ferreira, A.O.S.S. Rangel, J.L.F.C. Lima, Flow injection systems with stream splitting and a dialysis unit for the soil analysis of sodium and potassium by flame emission spectrometry, and calcium and magnesium by atomic absorption spectrophotometry, Commun. Soil Sci. Plant Anal. 26 (1995) 1532. 

The following replicate calcium determinations on a blood sample using atomic absorption spectrophotometry (AAS) and a new colorimetric method were reported. Is there a significant difference in the precision of the two methods ... 

The only common redox titration applied in the clinical laboratory is for the analysis of calcium in biological fluids. Calcium oxalate is precipitated and filtered, the precipitate is dissolved in acid, and the oxalate, which is equivalent to the calcium present, is titrated with standard potassium permanganate solution. This method is largely replaced now by more convenient techniques such as complex-ometric titration with EDTA (Chapter 9) or measurement by atomic absorption spectrophotometry (Chapter 17). 

Calcium S Atomic absorption spectrophotometry Dilute 1 20 with 10,000 ppm Na2EDTA and measure absorbance at 422.7 nm... 

EXPERIMENT 29 DETERMINATION OF CALCIUM BY ATOMIC ABSORPTION SPECTROPHOTOMETRY... 

Reference Method. Flame atomic absorption spectrophotometry (FAAS), considered as a reference method, is a sensitive and specific technique that can be used to measure calcium in whole blood, plasma, serum, urine, feces, and tissue samples [9]. However, in a clinical laboratory setting where calcium is routinely measured in plasma, serum, or urine, its use is often restricted to the measurement of urinary calcium. This is because of a lack of automation and therefore slower throughput of samples. 

The method of choice for the measurement of total calcium in tissue is atomic absorption spectrophotometry (AAS). Weighed aliquots of homogenized specimens are ashed. The ash is dissolved in dilute nitric acid and the acid digest is then analyzed for calcium by AAS. 

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