Chloride standard solution

The Bellar et al. [219] purge and trap method has been applied to the determination of vinyl chloride in seawater. Using the Hall electrolytic conductivity detector, no response was obtained for the acetone used to prepare the vinyl chloride standard solution. 

Construct a standard curve by repeating steps 1 to 6 without using oil or lipid extract sample. Instead of the sample, add to a series of 16 x 125-mm borosilicate glass tubes varying aliquots of an iron(III)-chloride standard solution (10 pg/ml), 50 pi of 10 mM xylenol orange solution, and enough 7 3 (v/v) chloroform/methanol solution to a final volume of 10 ml. 

Appropriate volumes of the iron(IIl) chloride standard solution should range from 0 to 2 ml. 

Salem et al. [48] reported simple and accurate methods for the quantitative determination of flufenamic, mefenamic and tranexamic acids utilizing precipitation reactions with cobalt, cadmium and manganese. The acidic drugs were precipitated from their neutral alcoholic solutions with cobalt sulfate, cadmium nitrate or manganese chloride standard solutions followed by direct determination of the ions in the precipitate or indirect determination of the ions in the filtrate by atomic absorption spectroscopy (AAS). The optimum conditions for precipitation were carefully studied. The molar ratio of the reactants was ascertained. Statistical analysis of the results compared to the results of the official methods revealed equal precision and accuracy. The suggested procedures were applied for determining flufenamic, mefenamic and... 

The accepted reference method for determining chloride in blood serum, plasma, urine, sweat, and other body fluids is the coulometric titration procedure. In this technique, silver ions are generated coulometrically. The silver ions then react with chloride ions to form insoluble silver chloride. The end point is usually detected by amperometry (see Section 23B-4) when a sudden increase in current occurs on the generation of a slight excess of Ag. In principle, the absolute amount of Ag" needed to react quantitatively with Cl can be obtained from application of Faraday s law. In practice, calibration is used. First, the time required to titrate a chloride standard solution with a known number of moles of chloride (nci )s using a constant current I is measured. The same constant current is next used in the titration of the unknown solution, and the time r is measured. The number of moles of chloride in the unknown (ncr)u is then obtained as follows ... 

Quantitative. Classically, silver concentration ia solution has been determined by titration with a standard solution of thiocyanate. Ferric ion is the iadicator. The deep red ferric thiocyanate color appears only when the silver is completely titrated. GravimetricaHy, silver is determined by precipitation with chloride, sulfide, or 1,2,3-benzotriazole. Silver can be precipitated as the metal by electro deposition or chemical reduciag agents. A colored silver diethjldithiocarbamate complex, extractable by organic solvents, is used for the spectrophotometric determination of silver complexes. 

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. 

Procedure. Prepare a standard (0.05M) solution of magnesium sulphate or chloride from pure magnesium (Section 10.60), an ammonia-ammonium chloride buffer solution (pH 10) (Section 10.54), and a standard (0.05M) solution of EDTA. 

The following sections are concerned with the use of standard solutions of reagents such as silver nitrate, sodium chloride, potassium (or ammonium) thiocyanate, and potassium cyanide. Some of the determinations which will be considered strictly involve complex formation rather than precipitation reactions, but it is convenient to group them here as reactions involving the use of standard silver nitrate solutions. Before commencing the experimental work, the theoretical Sections 10.74 and 10.75 should be studied. 

Prepare a standard ammonium chloride solution as follows. Dissolve 3.141 g ammonium chloride, dried at 100 °C, in ammonia-free water and dilute to 1 L with the same water. This stock solution is too concentrated for most purposes. A standard solution is made by diluting lOmL of this solution to 1 L with ammonia-free water 1 mL contains 0.01 mg of NH3. 

If necessary, dilute the sample to give an ammonia concentration of 1 mg L 1 and fill a 50 mL Nessler tube to the mark. Prepare a series of Nessler tubes containing the following volumes of standard ammonium chloride solution diluted to 50 mL 1.0,2.0,3.0,4.0,5.0, and 6.0 mL. The standards contain 0.01 mg NH3 for each mL of the standard solution. Add 1 mL of Nessler s reagent to each tube, allow to stand for 10 minutes, and compare the unknown with the standards in a Nessler stand (Section 17.4) or in a BDH Nesslerimeter. This will give an approximate figure which will enable another series of standards to be prepared and more accurate results to be obtained. 

Discussion. The turbidity of a dilute barium sulphate suspension is difficult to reproduce it is therefore essential to adhere rigidly to the experimental procedure detailed below. The velocity of the precipitation, as well as the concentration of the reactants, must be controlled by adding (after all the other components are present) pure solid barium chloride of definite grain size. The rate of solution of the barium chloride controls the velocity of the reaction. Sodium chloride and hydrochloric acid are added before the precipitation in order to inhibit the growth of microcrystals of barium sulphate the optimum pH is maintained and minimises the effect of variable amounts of other electrolytes present in the sample upon the size of the suspended barium sulphate particles. A glycerol-ethanol solution helps to stabilise the turbidity. The reaction vessel is shaken gently in order to obtain a uniform particle size each vessel should be shaken at the same rate and the same number of times. The unknown must be treated exactly like the standard solution. The interval between the time of precipitation and measurement must be kept constant. 

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. 

In a typical study of conductivity. Cook (1982) used a cell consisting of two platinum disc electrodes, 12 mm in diameter and 1-5 mm apart. The setting AB cement was examined in this cell which had been calibrated using a standard solution of0 02 M potassium chloride. Plots were recorded of spedfic conductance against time for each of the setting cements. For zinc polycarboxylate there was found to be a rapid drop in spedfic conductance about 10 minutes after the start of mixing. This behaviour was consistent with the replacement of relatively mobile protons by significantly less mobile zinc ions in the polycarboxylate chain. Con-... 

A sample of 0.4863 gram of this purified 0,0-diethyl O-p-nitrophenyl thiophosphate was dissolved in acetone to make 1 liter of standard solution. A 20-ml. aliquot, containing 9.73 mg., was placed in a 100-ml. volumetric flask and 30 ml. of acetone were added. Then 0.35 gram of potassium chloride and 0.6 gram of acetic acid were dissolved in about 25 ml. of water and added to the acetone solution 0.01 g am of gelatin was dissolved in a few milliliters of water by warming, cooled, and added to the above, and the... 

Assay preparation. Transfer not less than 20 Capsules to a blender jar or other container, and add about 150 mL of methylene chloride, and cool in a solid carbon dioxide acetone mixture until the contents have solidified. If necessary, transfer the mixture of capsules and methylene chloride to a blender jar, and blend with high-speed blender until all the solids are reduced to fine particles. Transfer the mixture to a 500-mL volumetric flask, add n-heptane to volume, mix, and allow solids to settle. Transfer an accurately measured volume of this solution, equivalent to 250 mg of valproic acid, to a 100 mL volumetric flask, dilute with w-heptane to volume, and mix. Transfer 5.0 mL to a container equipped with a closure. Add 2.0 mL of the internal standard solution, close the container, and mix. 

Chronopotentiometry has also been used to determine chloride ions in seawater [31]. The chloride in the solution containing an inert electrolyte was deposited on a silver electrode (1.1 cm2) by the passage of an anodic current. The cell comprised a silver disc as working electrode, a symmetrical platinum-disc counter-electrode and a Ag-AgCl reference electrode to monitor the potential of the working electrode. This potential was displayed on one channel of a two-channel recorder, and its derivative was displayed on the other channel. The chronopotentiometric constant was determined over the chloride concentration range 0.5 to 10 mM, and the concentration of the unknown solution was determined by altering the value of the impressed current until the observed transition time was about equal to that used for the standard solution. 

The vanadium eluate was slowly evaporated under an infrared lamp, the residue dissolved in 6 M hydrochloric acid (10 ml) containing 1 ml of the aluminium chloride solution [603], and vanadium was determined by atomic absorption spectrophotometry. For calibration, suitable standard solutions were aspirated before and after each batch of samples. 

An estimate of the accuracy of both analytical methods was performed on bis(tri-n-butyltin) oxide and tri-n-butyltin chloride solutions (8.9-35.6 ig/l) prepared in filtered (0.45 im) near-shore seawater free of detectable organ-otins. Average mean recoveries of 92.8% by both methods were determined for tributyltin standard solutions. Low ng/1 levels of mono-, di-, and tributyltin were found in samples taken from San Diego Bay. 

Spiking recoveries by the above procedure carried out on standard solutions of triphenyltin chloride in various types of water ranged from 74% at the 4 xg/l tin level (relative sd 8.9%) to 93.6% at the 2 mg/1 tin level (relative sd 4.2%). 

Standard solutions of potassium hydrogen phthalate, spiked with chloride, were also analysed. These results are compared with those given for the standard procedure in Table 11.4. 

EC is usually determined on solutions of salt in water. A soil sample is mixed with water until a paste, which is allowed to stand overnight, is obtained. The paste is then filtered and the EC of the solution measured. A conductivity cell for water is shown in Figure 9.6 (E). A sample is simply put in the cavity, or the cell is inserted into the extract, and a measurement made. Standardization is carried out by preparing standard solutions of salt, usually sodium chloride (NaCl), in distilled water. 

In Nebraska, state regulations require that the chemical makeup of animal feed sold in the state be accurately reflected on the labels found on the feed bags. The Nebraska State Agriculture Laboratory is charged with the task of performing the analytical laboratory work required. An example is salt (sodium chloride) content. The method used to analyze the feed for sodium chloride involves a potentio-metric titration. A chloride ion-selective electrode in combination with a saturated calomel reference electrode is used. After dissolving the feed sample, the chloride is titrated with a silver nitrate standard solution. The reaction involves the formation of the insoluble precipitate silver chloride. The electrode monitors the decrease in the chloride concentration as the titration proceeds, ultimately detecting the end point (when the chloride ion concentration is zero). 

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