Standard calcium solution

Prohexadione-calcium standard solutions Dissolve 10 mg of prohexadione-calcium in 100mL of water to prepare a lOOmgL" solution. Transfer 100 p.L of this solution into a 30-mL test-tube, evaporate water to dryness under reduced pressure and to methylate prohexadione-calcium according to Section 6.3. Dissolve the product in acetonitrile to prepare the 0.05,0.2,0.4,0.6 and 0.8 mgL acetonitrile solutions. 

Standard Solution Dilute a certified Calcium Standard Solution (NIST, or equivalent), quantitatively and stepwise, with water to obtain a Standard Solution containing 0.7 mg of calcium per milliliter of water. Store the Standard Solution in polyethylene bottles because of its instability in glass. 

A test solution is prepared by mixing 0.2 ml of alcoholic calcium standard solution (100 ppm Ca) R and 1 ml of ammonium oxalate solution R. After 1 min, a mixture of 1 ml of dilute acetic acid R and 15 ml of a solution containing the prescribed quantity of the substance to be examined is added and the solution is shaken. 

A standard is prepared in the same manner using a mixture of 10 ml of aqueous calcium standard solution (10 ppm Ca) ] , 1 ml of dilute acetic acid R, and 5 ml of distilled water R. After 15 min, any opalescence in the test solution should not be more intense than that in the standard. 

EGTA working solution 0.01 mol/L (or 0.005 mol/L for samples with a salinity of <20). Take aliquots of the stock solution and dilute to 0.01 mol/L. The empirical titre is determined by standardization with the calcium standard solution. 

Chemical Analysis. Standard chemical analyses have been developed for determining the concentration of various ions present in the mud [23]. Test for concentration of chloride, hydroxide and calcium ions are required to fill out the API drilling mud report. The tests are based on filtration, i.e., reaction of a known volume of mud filtrate sample with a standard solution of known volume and concentration. The end of chemical reaction is usually indicated by the change of color. The concentration of the ion being tested then can be determined from a knowledge of the chemical reaction taking place [7]. 

Similar to the pH meter, gas meters employ specific ion electrodes. The electrodes generate a potential proportional to the activity of a specific ion in solution. The calibration is achieved in standard solution and results read in mV or concentration in mg/L or ppm on the meter. The water can be adapted to monitor the concentration of carbon dioxide, hydrogen sulfide, ammonia, chloride, calcium, potassium and sodium to name a few. 

Hydrochloric acid and sulphuric acid are widely employed in the preparation of standard solutions of acids. Both of these are commercially available as concentrated solutions concentrated hydrochloric acid is about 10.5- 12M, and concentrated sulphuric acid is about 18M. By suitable dilution, solutions of any desired approximate concentration may be readily prepared. Hydrochloric acid is generally preferred, since most chlorides are soluble in water. Sulphuric acid forms insoluble salts with calcium and barium hydroxides for titration of hot liquids or for determinations which require boiling for some time with excess of acid, standard sulphuric acid is, however, preferable. Nitric acid is rarely employed, because it almost invariably contains a little nitrous acid, which has a destructive action upon many indicators. 

Nickel may be determined in the presence of a large excess of iron(III) in weakly acidic solution by adding EDTA and triethanolamine the intense brown precipitate dissolves upon the addition of aqueous sodium hydroxide to yield a colourless solution. The iron(III) is present as the triethanolamine complex and only the nickel is complexed by the EDTA. The excess of EDTA is back-titrated with standard calcium chloride solution in the presence of thymolphthalexone indicator. The colour change is from colourless or very pale blue to an intense blue. The nickel-EDTA complex has a faint blue colour the solution should contain less than 35 mg of nickel per 100 mL. 

Procedure. Prepare a standard calcium chloride solution (0.01 M) by dissolving 1.000 g of calcium carbonate in the minimum volume of dilute hydrochloric acid and diluting to 1 L with de-ionised water in a graduated flask. Also prepare a 20 per cent aqueous solution of triethanolamine. 

Procedure. Prepare a series of calcium ion solutions covering the concentration range 0-4 pg per 25 mL by adding sufficient of the 40 mg L 1 calcium standard to 25 mL graduated flasks each containing 5.0 mL of 0.4M potassium hydroxide solution and 1 mL of calcein solution. Dilute each to 25 mL using de-ionised water. Determine the fluorescence for each solution at 540 nm with excitation at either 330 nm or 480 nm, and plot a calibration curve. 

Preparation of the standard solutions. For procedure (i) it is necessary to incorporate a releasing agent in the standard solutions. Three different releasing agents may be used for calcium, (a) lanthanum chloride, (b) strontium chloride and (c) EDTA of these (a) is the preferred reagent, but (b) or (c) make satisfactory alternatives. 

Procedure (ii). Make certain that the instrument is fitted with the correct burner for an acetylene-nitrous oxide flame, then set the instrument up with the calcium hollow cathode lamp, select the resonance line of wavelength 422.7 nm, and adjust the gas controls as specified in the instrument manual to give a fuel-rich flame. Take measurements with the blank, and the standard solutions, and with the test solution, all of which contain the ionisation buffer the need, mentioned under procedure (i), for adequate treatment with de-ionised water after each measurement applies with equal force in this case. Plot the calibration graph and ascertain the concentration of the unknown solution. 

Glaser and Lichtenstein (G3) measured the liquid residence-time distribution for cocurrent downward flow of gas and liquid in columns of -in., 2-in., and 1-ft diameter packed with porous or nonporous -pg-in. or -in. cylindrical packings. The fluid media were an aqueous calcium chloride solution and air in one series of experiments and kerosene and hydrogen in another. Pulses of radioactive tracer (carbon-12, phosphorous-32, or rubi-dium-86) were injected outside the column, and the effluent concentration measured by Geiger counter. Axial dispersion was characterized by variability (defined as the standard deviation of residence time divided by the average residence time), and corrections for end effects were included in the analysis. The experiments indicate no effect of bed diameter upon variability. For a packed bed of porous particles, variability was found to consist of three components (1) Variability due to bulk flow through the bed... 

It is also possible to prepare a standard solution of calcium carbonate accurately using an analytical balance and a volumetric flask, as was suggested previously for EDTA, and pipetting an aliquot (a portion of a larger volume) of this solution into the reaction flask in preparation for the standardization of the EDTA solution. In this case, the concentration of the calcium carbonate solution is first calculated from the weight-volume preparation data (refer back to Example 4.2) and then the molarity of the EDTA solution is determined using Equation (5.54). 

Calcium Lactate Dissolve 0.5 g in DW add 2 ml of a 20% w/v soln. of iron-free-citric acid and 0.1 ml of thioglycollic acid, mix, make alkaline with iron-free-ammo-nia soln., dilute to 50 ml with DW and allow to stand for 5 minutes. Any colour produced is not more intense than that obtained by treating in the same manner 2.0 ml of iron standard solution (20 ppm Fe) in place of the soln. being examined. 

Sulphate stock standard solution, 500 pg mM of SO -S - dissolve 2.717 g potassium sulphate (K SO ), previously dried at 105°C for 1 h and cooled in a desiccator, in calcium phosphate extractant, then transfer to a 1-1 volumetric flask with washings and make up to the mark with extractant. 

Sulphate working standard solutions, 0-12 pg mM of SO -S - pipette 1, 2, 4, 6, 8 and 12 ml of the 500 pg mh sulphate stock standard solution into 500-ml volumetric flasks, make up to the mark with calcium phosphate extractant and mix. This will give solutions containing 1, 2, 4, 6, 8 and 12 pg mh of sulphate-S. 

Procedure. Carry out the extraction and then determine phosphorus as in Method 5.9a, except that working standard solutions should be made up in the Mehlich 1 extractant. Determine potassium and magnesium as in Method 5.10, except that standards are made up in Mehlich 1 extractant. Determine calcium as in Method 5.2, except that standards are made up in Mehlich 1 extractant. The composition of composts is so variable that appropriate dilutions of extracts may be required, and calculations adjusted accordingly. 

Stock standard solution, 2000 pg N mh 200 pg P mM, 1600 pg K mb, (400 pg Ca mb ) - omit the Ca if it is unlikely to be required, so as to avoid the precipitation of calcium sulphate in the diluted standards. This combined standard solution can be used for the autoanaiysis of P and K, and also provides a similar matrix to the sample digests. Each reagent should be dried at 102°C for 1 h and cooled in a desiccator before weighing. Dissolve 1.3745 g potassium chloride, 0.4393 g potassium dihydrogen phosphate, 4.7162 g ammonium sulphate, (and 0.5000 g calcium carbonate), in sulphuric acid (approximately 98% m/m H SO ) and make up to 500 ml with sulphuric acid. 

A standard solution was prepared in 50% acetonitrile and water having a known concentration of about 100. ig of glycerin per milliliter. Then 1.0 g of Nasonex was transferred into a 200-mL volumetric flask. About 30 mg of calcium chloride was added and diluted to volume with 50% acetonitrile in water and mixed. A portion of standard and sample solutions were filtered through a 0.45- xm nylon syringe filter. Equal volumes (1. iL) of standard and sample solutions were injected separately into the chromatographic system. 

Solutions Used in Hardness Determination. Standard Solution. It is prepared from a mixture of 0.1 N solutions of calcium and magnesiiun salts in the ratio 3 1. 

To prepare a 0.02 N standard solution of calcium and magnesium salts, pour 75 ml of a 0.1 N calcium chloride solution and 25 ml of a 0.1 TV magnesium sulphate solution into a 500-ml measuring flask, and then add distilled water up to the mark on the flask. 

A stock solution of calcium ions was prepared by dissolving 0.1834g of CaCl2.2H20 in 100 ml of distilled water and then further diluting by a factor of 10. From this new solution, three standard solutions were prepared by further dilutions of five, 10 and 20 times, respectively. The unknown sample is itself diluted 25 times. Sufficient strontium chloride was then introduced to eliminate any interference due to phosphate ions. An analytical blank containing the same concentration of strontium was the first solution to be examined by the air/acetylene flame. The results were as follows ... 

A standard solution of B-5 fixative containing a concentration of mercuric chloride of 60 g/1 was plated for 8 hours and yielded 60% recovered mercury metal. Two liters of solution were plated, thus a total of 120 g of mercuric chloride were processed. The stoichiometric amount of mercury metal from the reduction of 120 g of mercuric chloride equals 88 g. The recovered mercury metal totaled 53 g, thus demonstrating a 60% recovery efficiency. During the eight hour process the aluminum cathodes were changed once. The solution pH was between 3.6-3.8. 10 g of calcium chloride were added in order to... 

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