Nitrate standard solution

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). 

S04 see Conservative Elements). The analytical results reported by W. Dittmar in 1884 for waters collected during the British RMS Challenger Expedition (1872-1876) from the world s oceans were almost the same as today s values. The constancy of major chemical composition has led oceanographers to define salinity as a fundamental property together with temperature to calculate the density of sea water. It was routine for classic physical oceanographers to titrate sea water for chloride (plus bromide) ion with silver nitrate standard solution, until the mid 1960s when salinity could be determined more practically by measurement of conductivity. 

If the chloride content of the water sample is unknown this should first be determined by pre-titration with silver nitrate standard solution of appropriate normality. Take 100 ml of the filtered water sample with a chloride content of 1 - 15 mg, or a smaller volume diluted to 100 ml with distilled water. The pH should lie between 7 and 9 (acid- or alkaline-reacting waters should first be neutralized with chloride-free reagents). Add 1 ml of potassium chromate solution. 

Nitrate standard solution 1.011 g of dry potassium nitrate (KNO3) is dissolved and made up to 1 L with pure water. The stock solution contains 10 mmol/L nitrate and is stable. 

Silver compounds, available from commercial suppHers, are expensive. Reagent grades of sHver(I) carbonate, cyanide, diethjldithiocarbamate, iodate, nitrate, oxide, phosphate, and sulfate are available. Standardized solutions of silver nitrate are also available for analytical uses. Purified grades of sHver(I) acetate, bromide, cyanide, and iodide can be purchased silver nitrate is also made as a USP XX grade for medicinal uses (6). 

A mixture of tin(IV) and lead(II) ions may be complexed by adding an excess of standard EDTA solution, the excess EDTA being determined by titration with a standard solution of lead nitrate the total lead-plus-tin content of the solution is thus determined. Sodium fluoride is then added and this displaces the EDTA from the tin(IV)-EDTA complex the liberated EDTA is determined by titration with a standard lead solution. 

Procedure. Prepare a standard solution of lead nitrate (0.05M), a 0.05 per cent aqueous solution of xylenol orange indicator, and a 1,10-phenanthroline solution (0.05M) by dissolving 0.90 g of pure 1,10-phenanthroline in 1.5 mL of concentrated nitric acid and 100 mL of water. 

The titration error will increase with increasing dilution of the solution being titrated and is quite appreciable (ca 0.4 per cent) in dilute, say 0.01 M, solutions when the chromate concentration is of the order 0.003-0.005M. This is most simply allowed for by means of an indicator blank determination, e.g. by measuring the volume of standard silver nitrate solution required to give a perceptible coloration when added to distilled water containing the same quantity of indicator as is employed in the titration. This volume is subtracted from the volume of standard solution used. 

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. 

Discussion. Very pure silver can be obtained commercially, and a standard solution can be prepared by dissolving a known weight (say, 10.787 g) in nitric acid in a conical flask having a funnel in the neck to prevent mechanical loss, and making up to a known volume (say, 1 L for a 0.1 M solution). The presence of acid must, however, be avoided in determinations with potassium chromate as indicator or in determinations employing adsorption indicators. It is therefore preferable to employ a neutral solution prepared by dissolving silver nitrate (relative molecular mass, 169.87) in water. 

Analytical grade silver nitrate has a purity of at least 99.9 per cent, so that a standard solution can be prepared by direct weighing. If, however, commercial... 

Absorbance scale. This can be checked by using one or more standard solutions which have been carefully prepared examples include potassium dichromate in either acid or alkaline solution, and potassium nitrate solution. Full details of recommended standard solutions and of their standard absorption values are given in Ref. 19. 

Synthetic standard solution (for analysis of steel). Dissolve an appropriate weight of pure iron (Johnson Matthey) in a mixture of equal volumes of concentrated hydrochloric acid and concentrated nitric acid with this solution as base, add a suitable amount of copper nitrate solution containing 0.01 g copper per L. 

A weighed amount of sample is dissolved in a mixture of propanone and ethanoic acid and titrated potentiometrically with standard lead nitrate solution, using glass and platinum electrodes in combination with a ferro-ferricyanide redox indicator system consisting of 1 mg lead ferrocyanide and 0.5 ml 10% potassium ferricyanide solution. The endpoint of the titration is located by graphical extrapolation of two branches of the titration plot. A standard solution of sodium sulfate is titrated in the same way and the sodium sulfate content is calculated from the amounts of titrant used for sample and standard. (d) Water. Two methods are currently available for the determination of water. 

Based on the general scenario provided above, the analytical method to determine transference or transport numbers has been devised and is carried out in an apparatus which can essentially be regarded as an improvement over the Hittorf apparatus. This consists of two vertical tubes connected together with a U-tube in the middle all three tubes are provided with stop-cocks at the bottom. The U-tube is also provided with stop-cocks at the top by closing these, the solutions in the cathode and anode limbs can be isolated. The silver anode is sealed in a glass tube as shown, and the cathode is a piece of freshly silvered silver foil. The apparatus is filled up with a standard solution of silver nitrate and a steady current of about 0.01 ampere is passed for 2-3 hours. In order to avoid the occurrence of too large a change in concentration it is necessary to pass the current only for a short duration. The... 

Standard preparation Dissolve an accurately weighed quantity of USP Miconazole Nitrate RS in methanol to obtain a solution having a known concentration of about 500 pg/mL. Transfer 10 mL of this solution to a test tube, and evaporate on a steam bath with the aid of a current of filtered air to dryness. Dissolve the residue in 2 mL of the Internal standard solution. This Standard preparation has a concentration of about 2500 pg/mL. 

Internal standard solution, Standard preparation, and Chromatographic system Prepare as directed in the Assay under Miconazole nitrate cream. 

Stein et al. [673] have described a simplified, sensitive, and rapid method for determining low concentrations of cadmium, lead, and chromium in estuarine waters. To minimise matrix interferences, nitric acid and ammonium nitrate are added for cadmium and lead only nitric acid is added for chromium. Then 10,20, or 50 pi of the sample or standard (the amount depending on the sensitivity required) is injected into a heated graphite atomiser, and specific atomic absorbance is measured. Analyte concentrations are calculated from calibration curves for standard solutions in demineralised water for chromium, or an artificial seawater medium for lead and cadmium. 

The effect of ammonium nitrate concentration on the peak height of a 60ng Atrazine standard solution is shown in Fig. 9.8, the optimum response being at a concentration of approximately 4pg pL-1. 

To check the enhancement effect in the presence of soil extracts, soil was treated with ammonium nitrate at a rate equivalent to 200kg ha-1. When 50g of the soil were extracted with 100ml of methanol using the method of Byast et al. [101] the concentration of ammonium nitrate in solution was about 4pg pL-1. Injections of the treated soil extract increased the peak height of a subsequent 60ng Atrazine standard by 55-65%. No increase occurred following injections of untreated soil extracts. 

The following data were obtained using a nitrate electrode for a series of standard solutions of nitrate ... 

Standard Lead Solution On the day of use, dilute 10.0 ml of lead nitrate stock solution with DW to 100.0 ml. Each ml of standard lead solution contains the equivalent of 10 microgrammes of lead. A control comparison solution prepared with 2.0 ml of standard lead solution contains, when compared to a solution representing 1.0 g of the substance being tested, the equivalent of 20 parts per million of lead. 

The following substance, namely magnesium acetate potassium citrate potassium hydroxide potassium nitrate and sodium chloride can also be assayed for their respective elements as shown in Table 25.1 below. However, all the respective solutions of the said pharmaceutical substance and their standard solutions must be prepared as prescribed in BP (1993) strictly to obtain the best results. 

Because the major ions are present in nearly constant proportions, the salinity of seawater can be inferred from any of their individual concentrations. The easiest concentration to measure is that of the chloride ion, which is also the most abundant. In practice, this concentration is determined by titrating a sample of seawater with a standardized solution of silver nitrate. The reactions that take place are ... 

Nitrate stock standard solution, 0.2 mg mh nitrate-N - dissolve 0.722 g of potassium nitrate in 0.01 M CaSO solution, dilute to 500 ml and store in a refrigerator. 

Nitrate working standard solution, 1-100 pg mh nitrate-N - pipette 0.5, 2, 5, 10, 25 and 50 ml of the stock standard into 100-ml volumetric flasks and make up to the mark with 0.01 M CaSO solution and mix. 

Nitrate-N standard solution, 0.14 mg mh nitrate-N - dissolve 1.011 g potassium nitrate (oven-dry) in water, transfer with washings to a 1-1 volumetric flask, make up to the mark and mix. 

Procedure. Pipette 5 ml nitrate-N standard solution into the distillation flask, add 1 drop octan-2-ol, approximately 0.5 g Devarda s alloy, 6 ml magnesium hydroxide suspension (or 0.5 g MgO), and steam-distil the ammonia into 5-ml boric acid solution in a 100-ml conical flask. After approximately 40 ml distillate has been collected over a 5-min period, wash the tip of the condenser into the distillate, add 2-3 drops mixed indicator solution and titrate with 0.005 M HjSO until the colour changes from green to purple. Carry out a blank distillation using 5 ml water instead of extract solution and subtract from the standard titration to give a difference of 5.0 ml. 

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