Enzymatic method for assaying calcium in serum and urine with porcine pancreatic alpha-amylase

1994 ◽  
Vol 40 (5) ◽  
pp. 781-784 ◽  
Author(s):  
Y Kayamori ◽  
Y Katayama
Keyword(s):  
Atomic Absorption ◽  
Serum Calcium ◽  
Atomic Absorption Spectrophotometry ◽  
Alpha Amylase ◽  
Enzymatic Method ◽  
Kinetic Assay ◽  
Urine Calcium ◽  
Absorption Spectrophotometry ◽  
Highly Sensitive ◽  
Serum And Urine

Abstract We developed a kinetic assay for calcium in serum and urine, based on the activation of porcine pancreatic alpha-amylase (EC 3.2.1.1) with 2-chloro-4-nitrophenyl-alpha-maltotrioside as substrate. The kinetic generation of 2-chloro-4-nitrophenol, monitored at 405 nm, was proportional to the concentration of calcium in serum and urine. The assay was developed and evaluated with the Cobas Bio centrifugal analyzer. The average within-run and between-day imprecision (CV) was 0.96/1.26% and 1.07/1.63%, respectively, for serum calcium and 1.50/2.54% and 1.70/2.64%, respectively, for urine calcium. Results of the proposed method (y) correlated well with those determined by atomic absorption spectrophotometry (x): y(serum) = 1.005x + 0.028 mmol/L (Sy/x = 0.058, r = 0.974, n = 50), and y(urine) = 1.017x-0.115 mmol/L Sy/x = 0.30, r = 0.981, n = 25). We also present data showing that the method is highly sensitive, rapid, relatively free of interference, and amenable to automation.

Assay of magnesium in serum and urine with use of only one enzyme, isocitrate dehydrogenase (NADP+)

1995 ◽  
Vol 41 (9) ◽  
pp. 1302-1305 ◽  
Author(s):  
T Fujita ◽  
Y Kawakami ◽  
S Kohda ◽  
S Takata ◽  
Y Sunahara ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Isocitrate Dehydrogenase ◽  
Atomic Absorption Spectrophotometry ◽  
Magnesium Ion ◽  
Absorption Spectrophotometry ◽  
Metal Chelating ◽  
Analytical Recovery ◽  
Enzymatic Reduction ◽  
Chelating Reagents ◽  
Serum And Urine

Abstract We report a method for assaying magnesium in serum and urine involving only one enzyme, isocitrate dehydrogenase (NADP+)(EC 1.1.1.42), which requires magnesium ion for activity. The enzymatic reduction of NADP+ by isocitrate increases in rate linearly up to at least 20 mmol/L magnesium in the presence of appropriate concentrations of the two metal-chelating reagents, EDTA and glycol ether diamine-N,N,N',N'-tetraacetate. Within-run (n = 20) CVs and day-to-day (n = 10) CVs for sera are < or = 1.5% and < or = 2.6%, respectively. Analytical recovery of magnesium in sera averages 96-100%. This method is not affected by bilirubin, hemoglobin, or lipemia. The method (y) gives the following results correlating with atomic absorption spectrophotometry (x): y = 1.03x + 0.06 mmol/L (n = 62, r = 0.995, Sylx = 0.03) for sera, and y = 1.03x - 0.10 mmol/L (n = 62, r = 0.989, Sylx = 0.19) for urines; with the calmagite method (x): y = 0.99x + 0.04 mmol/L (n = 62, r = 0.991, Sylx = 0.03) for sera, and y = 0.98x + 0.03 mmol/L (n = 62, r = 0.999, Sylx = 0.02) for urines.

Comparison of Serum Calcium Measurements Obtained with the SMA 12/60 and by Atomic Absorption Spectrophotometry

1971 ◽  
Vol 17 (10) ◽  
pp. 1047-1049 ◽  
Author(s):  
S Raymond Gambino ◽  
Ivelice Fonseca
Keyword(s):  
Atomic Absorption ◽  
Serum Calcium ◽  
Large Scale ◽  
Colorimetric Assay ◽  
Internal Standard ◽  
Reference Method ◽  
Atomic Absorption Spectrophotometry ◽  
Laboratory Model ◽  
Absorption Spectrophotometry ◽  
The Difference

Abstract Comparable results are obtained when serum calcium is measured by a colorimetric cresolpthalein method on the Technicon SMA 12/60 and by atomic absorption spectrophotometry (Instrumentation Laboratory Model 153 instrument), with strontium as an internal standard. Sera from 250 patients with abnormal calcium concentrations, ranging from 4.9 mg/100 ml to 9.0 mg/100 ml, were measured by each method; the difference between the means for each method was only 0.04 mg/100 ml. The standard deviation of the difference between paired results was ±0.16 mg/100 ml. We were unable to discover any effect of drug or disease on the colorimetric assay, which therefore is suitable for use in large-scale surveys. On the other hand, the more precise atomic absorption spectrophotometry is suitable for use as a reference method. In addition, with an internal standard it is fast and simple, making it suitable for emergency assays of calcium 24 h a day.

Application of Atomic Absorption Spectrophotometry in the Determination of Calcium in Serum

1964 ◽  
Vol 10 (10) ◽  
pp. 869-890 ◽  
Author(s):  
Alfred Zettner ◽  
David Seligson
Keyword(s):  
Calcium Oxalate ◽  
Atomic Absorption ◽  
Serum Calcium ◽  
Atomic Absorption Spectrophotometry ◽  
Dilution Technique ◽  
Serum Samples ◽  
Absorption Spectrophotometry

Abstract Atomic absorption spectrophotometry (AAS) was applied to the determination of serum calcium. A special diluent was developed to abolish the effect of absorption depressors. This made possible measurement of calcium in directly diluted serum samples without prior removal of any serum constituents. Values obtained by AAS on calcium oxalate precipitates from serum were identical with those found by the direct dilution technique.

Determination of Serum Calcium by Automated Atomic Absorption Spectroscopy

1967 ◽  
Vol 13 (5) ◽  
pp. 388-396 ◽  
Author(s):  
Bernard Klein ◽  
James H Kaufman ◽  
Stanley Morgenstern
Keyword(s):  
Hydrochloric Acid ◽  
Atomic Absorption ◽  
Serum Calcium ◽  
Flow System ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Comparison Of The Results ◽  
Automated Determination ◽  
Good Agreement

Abstract A procedure is presented for the automated determination of serum calcium by atomic absorption spectrophotometry. The serum sample, diluted with acidified lanthanum dichloride, is dialyzed against 0.1 N hydrochloric acid and a portion of the recipient solution is pumped into the atomizer-burner of the spectrophotometer. Data are presented on the precision and reproducibility of the flow system. Addition of calcium to serum shows a mean recovery of 99%. A comparison of the results of analyses on random specimens by permanganate titration and the automated procedure shows good agreement.

Evaluation of the Corning 940 Calcium Titrator for Use with Serum and Urine

1975 ◽  
Vol 21 (2) ◽  
pp. 264-267 ◽  
Author(s):  
Earl B Weissman ◽  
Desider A Pragay ◽  
Charles Bishop
Keyword(s):  
Atomic Absorption ◽  
Continuous Flow ◽  
Calcium Concentration ◽  
Atomic Absorption Spectrophotometry ◽  
Tetraacetic Acid ◽  
Total Calcium ◽  
Absorption Spectrophotometry ◽  
Coefficients Of Variation ◽  
Serum And Urine ◽  
High Range

Abstract The Corning 940 Titrator, which measures total calcium concentration by titration with [ethylenebis(oxyethylenenitrilo)]tetraacetic acid, was evaluated for use in a hospital laboratory. Calcium values for patients' sera were about 0.3 mg/dl lower as measured with the Titrator than with the Technicon SMA 12/60 continuous-flow analyzer. A similar bias was evident when the results with the Titrator were compared with those from atomic absorption spectrophotometry. Agreement was better in the low range and worse in the high range. Within-day and between-day coefficients of variation on the Titrator were about 1.5% and 2.5%, respectively. We saw no interference from magnesium, phosphorus, bilirubin, or in the presence of lipemia. At extremely increased hemoglobin concentrations (500 mg/dl), there is a 5% inhibition. Titrator results for patients' urine samples correlated closely (n = 0.999) with those obtained with the SMA 12/60.

Automated Atomic Absorption Spectrophotometry

1967 ◽  
Vol 13 (9) ◽  
pp. 788-796 ◽  
Author(s):  
Bernard Klein ◽  
James H Kaufman ◽  
Morris Oklander
Keyword(s):  
Atomic Absorption ◽  
Excellent Agreement ◽  
Serum Calcium ◽  
Flow System ◽  
Serum Magnesium ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Present Procedure ◽  
Comparison Of The Results

Abstract The flow system developed for the determination of serum calcium by automated atomic absorption spectrophotometry (AAS) was adapted to the determination of serum magnesium. A comparison of the results of analyses by the present procedure and by an automated fluorometric procedure on identical serum specimens shows excellent agreement.

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