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Quantitation calcium

Rodriguez-Moreno A, Lopez-Garcia JC, Lerma J (2000) Two populations of kainate receptors with separate signaling mechanisms in hippocampal intemeurons. PNAS 97 1293-8 Rodriguez-Moreno A, Sihra TS (2004) Presynaptic kainate receptor facilitation of glutamate release involves protein kinase A in the rat hippocampus. J Physiol (Lond) 557 733—45 Rogers M, Dani JA (1995) Comparison of quantitative calcium flux through NMDA, ATP, and ACh receptor channels. Biophys J 68 501-6... [Pg.524]

A combination of STEM and either energy dispersive X-ray microanalysis (see below) or electron energy loss can detect low elemental concentrations at the subcellular level. Leapman and Andrews (16) reported the ability to quantitate calcium in Purkinje cell dendrites to an accuracy of < 12 atoms. A low tempera-... [Pg.82]

WiNDiscH W and Kiechgessnee M (1994a) Distribution of calcium and zinc, and zinc exchange in tissues at deficient and moderately high calcium supply. 2. Effect of differing calcium supplies on the quantitative calcium and zinc in the metabolism of adult rats. J Anim Physiol Anim Nutr 72 195-206. [Pg.1238]

Minimizing Chemical Interferences The quantitative analysis of some elements is complicated by chemical interferences occurring during atomization. The two most common chemical interferences are the formation of nonvolatile compounds containing the analyte and ionization of the analyte. One example of a chemical interference due to the formation of nonvolatile compounds is observed when P04 or AP+ is added to solutions of Ca +. In one study, for example, adding 100 ppm AP+ to a solution of 5 ppm Ca + decreased the calcium ion s absorbance from 0.50 to 0.14, whereas adding 500 ppm POp to a similar solution of Ca + decreased the absorbance from 0.50 to 0.38. These interferences were attributed to the formation of refractory particles of Ca3(P04)2 and an Al-Ca-O oxide. [Pg.419]

Most potentiometric electrodes are selective for only the free, uncomplexed analyte and do not respond to complexed forms of the analyte. Solution conditions, therefore, must be carefully controlled if the purpose of the analysis is to determine the analyte s total concentration. On the other hand, this selectivity provides a significant advantage over other quantitative methods of analysis when it is necessary to determine the concentration of free ions. For example, calcium is present in urine both as free Ca + ions and as protein-bound Ca + ions. If a urine sample is analyzed by atomic absorption spectroscopy, the signal is proportional to the total concentration of Ca +, since both free and bound calcium are atomized. Analysis with a Ca + ISE, however, gives a signal that is a function of only free Ca + ions since the protein-bound ions cannot interact with the electrode s membrane. [Pg.489]

Quantitative Analysis. OxaUc acid is precipitated as calcium oxalate from a solution containing oxaUc acid, and the calcium oxalate obtained is then weighed. If there are no organic substances other than oxaUc acid present, oxaUc acid can be titrated quantitatively with potassium permanganate. [Pg.461]

Calcium Oxalate. The monohydrate [5794-28-5], CaC2 04-H2 0, mol wt 128.10,is of importance principally as an intermediate in oxahc acid manufacture and in analytical chemistry it is the form in which calcium is frequentiy quantitatively isolated. Its solubihty in water is very low, lower than that of the other aLkahne-earth oxalates. The approximate solubihties of this and several related salts are indicated in Table 6. [Pg.462]

Tricalcium Phosphate. Commercial tricalcium phosphate (TCP) is actually an amorphous basic calcium phosphate close to hydroxyapatite in composition. Because of its extremely low solubiUty in water, TCP is precipitated almost quantitatively from dilute phosphate solutions with a slurry of hydrated lime. TCP is separated by dmm-, spray-, or flash-drying the TCP slurry, with or without intermediate sedimentation or filtration steps. It is used as an industrial-grade flow conditioner and parting agent. [Pg.342]

The LSI measures only the directional tendency or driving force for calcium carbonate to precipitate or dissolve. It caimot be used as a quantitative measure. Two different waters, one of low hardness (corrosive) and the other of high hardness (scale-forrning), can have the same saturation index. [Pg.269]

Base catalyzed pinacol rearrangement of vicinal m-glycol monotosylates is a simple and useful general method for preparing perhydroazulenes. Thus, treatment of cholestane-5a,6a-diol 6-tosylate (115a) with either one mole-equivalent of potassium t-butoxide in f-butanol at 25° or with calcium carbonate in dimethylformamide at 100° gives a quantitative yield of 10(5 6/5H)... [Pg.392]

A simple and direct approach to 10(5 4j H)<2Z)eo-5-lceto derivatives lacking functionality in ring A is the controlled pinacol rearrangement of vicinal cw-diols analogous to the process described in the previous section. An example is the reaction of cholestane-4a,5a-diol 4-tosylate (136) with 1 mole-equivalent of potassium t-butoxide or with dimethylforraamide-calcium carbonate at reflux which gives a quantitative yield of Q(5ApH)abeo-cholestan-5-one (137). ... [Pg.398]

A -(l-Haloalkyl)pyridinium halides have been advantageously employed in the Hantzsch multicomponent synthesis, yielding alkyl 1,4-dihydropyri-dine-3,5-dicarboxylates, which are a well-known class of calcium channel modulators (81AGE762). Tire halides readily interact with an excess of an ethyl 3-aminobut-2-enoate 82 (R = H) in dichloromethane at room temperature to afford the heterocycles 83 (R = H) in good to excellent yields (65-95%) (92T1263). Tliis observation has been exploited to perform a quantitative study of the reactivity of the salts (93CB1251).Tlie results have... [Pg.210]

There are numerous second messenger systems such as those utilizing cyclic AMP and cyclic GMP, calcium and calmodulin, phosphoinosiddes, and diacylglerol with accompanying modulatory mechanisms. Each receptor is coupled to these in a variety of ways in different cell types. Therefore, it can be seen that it is impractical to attempt to quantitatively define each stimulus-response mechanism for each receptor system. Fortunately, this is not an... [Pg.24]

The solubility of most inorganic compounds is reduced by the addition of organic solvents, such as methanol, ethanol, propan-l-ol, acetone, etc. For example, the addition of about 20 per cent by volume of ethanol renders the solubility of lead sulphate practically negligible, thus permitting quantitative separation. Similarly calcium sulphate separates quantitatively from 50percent ethanol. Other examples of the influence of solvents will be found in Chapter 11. [Pg.30]

Solochrome dark blue or calcon ( C.1.15705). This is sometimes referred to as eriochrome blue black RC it is in fact sodium l-(2-hydroxy-l-naphthylazo)-2-naphthol-4-sulphonate. The dyestuff has two ionisable phenolic hydrogen atoms the protons ionise stepwise with pK values of 7.4 and 13.5 respectively. An important application of the indicator is in the complexometric titration of calcium in the presence of magnesium this must be carried out at a pH of about 12.3 (obtained, for example, with a diethylamine buffer 5 mL for every 100 mL of solution) in order to avoid the interference of magnesium. Under these conditions magnesium is precipitated quantitatively as the hydroxide. The colour change is from pink to pure blue. [Pg.318]

Calcon may also be used for the titration of calcium in the presence of magnesium (compare Section 10.48). The neutral solution (say, 50 mL)is treated with 5 mL of diethylamine (giving a pH of about 12.5, which is sufficiently high to precipitate the magnesium quantitatively as the hydroxide) and four drops... [Pg.329]

Notes. (1) The usefulness of the HHSNNA indicator for the titration of calcium depends upon the fact that the pH of the solution is sufficiently high to ensure the quantitative precipitation of the magnesium as hydroxide and that calcium forms a more stable complex with EDTA than does magnesium. The EDTA does not react with magnesium [present as Mg(OH)2] until all the free calcium and the calcium-indicator complex have been complexed by the EDTA. If the indicator is added before the potassium hydroxide, a satisfactory end-point is not obtained because magnesium salts form a lake with the indicator as the pH increases and the magnesium indicator-lake is co-precipitated with the magnesium hydroxide. [Pg.331]

Calcium in calcium carbonate. Determine the calcium in an analysed sample of dolomite. Dissolve about 0.38 g, accurately weighed in 1 1 hydrochloric acid, warm gently, filter through a quantitative filter paper, wash, dilute the combined filtrate and washings to 1 L. Measure the calcium content of the resulting solution use a calcium filter. Compare the value for Ca thus obtained with the known Ca content. [Pg.813]

We have not demonstrated quantitative phase separation of salt from metal in the oxidation step. Approximately 5% of the gallium was carried over from the feed to the product after the calcium reduction. We are now scaling-up the 100-g experiments to plant-size equipment using magnesia crucibles in the equipment shown in Figure 3. [Pg.422]

Use of biochemical and biological information for bioprocesses is also significant to the advancement of BRE. Here, the information on the signal transduction from external Ca was utilized for regulation of ginsenoside biosynthetic pathway of cultured cells of P. notoginseng. A quantitative study on the effects of external calcium and calcium sensors was conducted to... [Pg.92]

The analysis can be made quantitative by writing the various equilibria and their values. The reactions can be added to obtain the net reaction that occurs when calcium carbonate is exposed to acidic water, and the equilibrium constant for the net reaction is the product of the individual. S eq values ... [Pg.1319]

Shi, H., Zhang, R., Chandrasekher, G., and Ma, Y., Simultaneous detection and quantitation of sodium, potassium, calcium and magnesium in ocular lenses by high-performance capillary electrophoresis with indirect photometric detection, ]. Chromatogr. A, 680, 653 1994. [Pg.422]

SK Joseph, JR Williamson. (1983). The origin, quantitation, and kinetics of intracellular calcium mobilization by vasopressin and phenylephrine in hepatocytes. J Biol Chem 258 10425-10432. [Pg.389]


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