Calcium test

Two identification tests for oxytetracycline hydrochloride are given in the USP 28 [1], one being an ultraviolet absorption test and the other a color test. European Pharmacopoeia [2], British Pharmacopoeia (BP) 2003 [4], International Pharmacopoeia [5], and Pharmacopoeia of the People s Republic of China [6] described a thin-layer chromatography and color tests for identification of oxytetracycline hydrochloride and oxytetracycline dihydrate. For identification of oxytetracycline calcium, USP 28 [1] used Method II under identification of tetracycline <193>, whilst BP 2003 [4] described a TLC, color test, and calcium test as the method of identification. 

El95 Ektachem Calcium Test Methodology, M6B034 1-86-0 Reprint (1985). 

Urine calcium levels will indicate the amount of calcium being excreted in the urine. Additionally, an ionized calcium test may be performed to measure the amount of calcium that is not bound to protein in the blood. The level of ionized calcium in the blood is not affected by the amount of protein in the blood. 

Saenger, P., Rosen, J.F., Markowitz, MJi., 1982. Diagnostic significance of edetate disodium calcium testing in children with increased lead absorption. Am. J. Dis. Child. 136, 312-315. 

If the calcium test is carried out in a micro test tube, the reaction succeeds down to dilutions of 1 1,000,000 see F. Feigl and F. Pavelka, Mikrochemie 2 (1924) 85. Small traces of cloudiness are always dififtcult to see in single drops, because the layer observed is too thin. 

Calcium, Test with ammonium ferrocyanide, see page 158. 

Monitoring Therapy A high-dose calcium test may be used as a potent biomarker for the diagnosis and follow-up of medullary thyroid cancer (MTC), since it is well tolerated and is cost effective compared to the pentagastrin test. A recent study identified that the best levels of basal calcitonin (bCT) to distinguish normal and C-cell hyperplasia (CCH) cases, from MTC patients were above 18.7pg/ml in females and above 68pg/ml in males while calcium-stimulated calcitonin levels above 184 pg/ml in females and above 1620pg/ml in males were most accurate to separate normal and CCH cases from patients with MTC [74 ]. 

Saenger, P., Rosen, J.F. and Markowitz, M.E. (1982) Diagnostic significance of edetate disodium calcium testing in children with increased lead absorption. Am. J. Dis. Child., 136, 312-315 Schroeder, S.R., Hawk, B., Otto, D.A., Mushak, P. and Hicks, R.E. (1985) Separating the effects of lead and social factors on IQ. Environ. Res., 38, 144-154 Shapiro, I.M., Needleman, H.L. and Tuncay, O.C. (1972) The lead content of human deciduous and permanent teeth. Environ. Res., 5, 467-470 Shapiro, I.M., Dobkin, B., Tuncay, O.C. and Needleman, H.L. (1973) Lead levels in dentine and circumpulpal dentine of deciduous teeth of normal and lead poisoned children. Clin. 

Transparent barrier coatings are desired in the packaging industry in order to allow the customer to see the product. Barrier coatings are also of great interest in the display industry. The calcium test, which uses the oxidation of a calcium film as the indicator, is the most sensitive test for oxygen and water vapor permeation,... 

Calcium test (permeation) A test for water permeation through a membrane converts opaque metallic calcium to transparent calcium hydroxide... 

In similar circumstances, silver salts leave a residue of metallic silver lead and copper salts usually leave a residue of the corresponding oxide calcium and barium salts leave a resirlne of the carbonate or oxide. Identify the metal in all such cases by the usual tests of qualitative inorganic analysis. Metals other than the above are seldom encountered in elementan qualitative analysis. 

Caldum chloride test. Add CaCl2 solution to a neutrai solution of an oxalate a white precipitate of calcium oxalate is formed, insoluble in acetic acid, but soluble in dil. HCl. 

It should be emphasised that the calcium chloride solution used in testing for acids is of Reagent concentration (p. 524) throughout. 

Certain salts of divalent metals (e.g., lead and copper formate, calcium acetate) are exceptional in giving bright green fluorescences. In each case confirmatory tests must always be employed. 

Di-n-butyl ether. Technical n-butyl ether does not usually contain appreciable quantities of peroxides, unless it has been stored for a prolonged period. It should, however, be tested for peroxides, and, if the test is positive, the ether should be shaken with an acidified solution of a ferrous salt or with a solution of sodium sulphite (see under Diethyl ether). The ether is dried with anhydrous calcium chloride, and distilled through a fractionating column the portion, b.p. 140-141°, is collected. If a fraction of low boiling point is obtained, the presence of n-butyl... 

Prepare a solution containing about 100 g, of potassium hypochlorite from commercial calcium hypochlorite ( H.T.H. ) as detailed under -Dimethylacrylic Acid, Section 111,142, Note 1, and place it in a 1500 ml. three-necked flask provided with a thermometer, a mechanical stirrer and a reflux condenser. Warm the solution to 55° and add through the condenser 85 g, of p-acetonaphthalene (methyl p-naphthyl ketone) (1). Stir the mixture vigorously and, after the exothermic reaction commences, maintain the temperature at 60-70° by frequent cooling in an ice bath until the temperature no longer tends to rise (ca. 30 minutes). Stir the mixture for a further 30 minutes, and destroy the excess of hypochlorite completely by adding a solution of 25 g. of sodium bisulphite in 100 ml. of water make sure that no hypochlorite remains by testing the solution with acidified potassium iodide solution. Cool the solution, transfer the reaction mixture to a 2-litre beaker and cautiously acidify with 100 ml. of concentrated hydrochloric acid. Filter the crude acid at the pump. 

The most common interfering substance, especially with alcohols of low mole cular weight, is water this may result in an inaccurate interpretation of the test if applied alone. Most of the water may usually be removed by shaking with a little anhydrous calcium sulphate,. though dry ethers (and also the saturated aliphatic and the simple aromatic hydrocarbons) do not react with sodium, many other classes of organic compounds do. Thus ... 

Sodium test. Treat 1 ml. of the compound with a amall thin slice of freshly cut sodium (handle with the tonga or with a penknife) in a small, dry test-tube (75 X 10 mm. or 100 X 12 mm.). Observe whether hydrogen is evolved and the sodium reacts. (If the compound is suspected to contain water, dry it first with a little anhydrous calcium or magnesium sulphate.)... 

Eluorspar assay may be completed by fluoride determination alone, because the mineralogical grouping rarely iacludes fluorine minerals other than fluorite. Calcium can be determined as oxalate or by ion-selective electrodes (67). SiUca can be determined ia the residue from solution ia perchloric acid—boric acid mixture by measuriag the loss ia weight on Aiming off with hydrofluoric acid. Another method for determining siUca ia fluorspar is the ASTM Standard Test Method E463-72. 

The test formulation contains 100 parts of PVC (Fikentscher K = 65), 1.2 parts of paraffin wax, 0.6 parts of calcium stearate, and 0.4 parts of methyitin-based stabilizers. 

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