Hydroxylamine hydrochloride solution

Determine (a) the pH of a 0.0240 m hydroxyl-ammonium chloride (more commonly called hydroxylamine hydrochloride) solution (b) the pH of 0.010 M Na2C03(aq). 

For quality control, the residue from step 3 has to be digested in aqua regia ( step 4 ) and the cumulative amount of metal extracted [i.e. 2(step 1 + step 2 + step 3 + step 4 )] is compared with the pseudototal amount of metal obtained by aqua regia digestion of a separate 1-g soil sample. In the modified BCR procedure, a 0.5 M hydroxylamine hydrochloride solution at pH 1.5 is applied in step 2. 

C. Preparation of the reducing agent. One hundred and twenty-five grams (0.5 mole) of cupric sulfate pentahydrate is dissolved in 500 ml. of water contained in a 3-1. three-necked flask equipped with a mechanical stirrer, and then 210 ml. of concentrated ammonium hydroxide (sp. gr. 0.90) is added with stirring. The solution is cooled to 10°. A solution of 40 g. (0.575 mole) of hydroxylamine hydrochloride in 140 ml. of water is prepared and also cooled to 10°. To the hydroxylamine hydrochloride solution there is added 95 ml. of 6 A sodium hydroxide solution, and if not entirely clear, it is filtered by suction. This hydroxylamine solution is immediately added to the ammoniacal cupric sulfate solution with stirring. Reduction occurs at once with the evolution of nitrogen, and the solution becomes pale blue. If this solution is not used at once, it should be protected from the air. 

Hydroxylamine Hydrochloride Solution Prepare a 0.5 N solution by dissolving 35.0 g of hydroxylamine hydrochloride in water contained in a 1-L volumetric flask, dilute to volume with water, and mix. 

Procedure Adjust to pH 3.60 a volume of Hydroxylamine Hydrochloride Solution sufficient for analyzing both the blank and the sample. Using a suitable autotitrator, titrate with Triethanolamine Solution. 

Transfer 65.0 mL of the pH 3.60 Hydroxylamine Hydrochloride Solution into each of two titration cups. Add a Teflon (or equivalent) stirrer to each cup. Using the autotitrator, add 30.8 mL of the neutralized Triethanolamine Solution to each titration cup, cover, and mix. Using a weighing pipet, introduce into one of the cups a suitable portion of sample equivalent to about 300 mg of Glutaraldehyde. Mix the solutions thoroughly, and allow the sample and blank to stand at room temperature for at least 60 min but not for more than 90 min. 

Procedure Transfer 100 mL of Standard Solution to a 300-mL mercury analysis reaction vessel, add 2 drops of a 1 20 potassium permanganate solution, and mix (the solution should be purple add additional permanganate solution, drop-wise, if necessary). Add 5 mL of 11 A nitric acid, stir, and allow to stand for not less than 15 s. Add 5 mL of 18 A sulfuric acid, stir, and allow to stand for not less than 45 s. Add 5 mL of a 3 200 hydroxylamine hydrochloride solution, stir, and allow to stand until the solution turns light yellow or colorless. Add 5 mL of a 1 10 stannous chloride solution, immediately insert the aerator connected to an air pump, and determine the maximum absorbance of the treated Standard Solution at the mercury resonance line of 253.65 nm, with a suitable atomic absorption spectrophotometer equipped with a mercury hollow-cathode lamp and an absorption cell that permits the flameless detection of mercury. 

Hydroxylamine Hydrochloride Solution Dissolve 20 g of hydroxylamine hydrochloride in sufficient water to make about 65 mL, transfer the solution into a separator, add a few drops of thymol blue TS, and then add ammonium hydroxide until a yellow color appears. Add 10 mL of 1 25 sodium... 

Sample Solution Transfer 1 g of sample into a 250-mL beaker, add 20 mL of 1 2 nitric acid, and digest on a steam bath for about 45 min. Add 5 mL of 1 3 hydrochloric acid, and continue heating on the steam bath until the sample is dissolved. Cool to room temperature, and filter, if necessary, through a medium-porosity filter paper. Wash the paper with a few milliliters of water, add 20 mL of Sodium Citrate Solution and 1 mL of Hydroxylamine Hydrochloride Solution to the filtrate, and adjust the pH to 1.8 with ammonium hydroxide. 

Procedure (Note Refer to Lead Limit Test, Appendix TTTR, for the solutions and the control.) Add 3 mL of Ammonium Citrate Solution and 0.5 mL of Hydroxylamine Hydrochloride Solution to the Sample Solution, and make the combined solutions alkaline to phenol red TS with ammonium hydroxide. Add 10 mL of Potassium Cyanide Solution. Immediately extract the solution with successive 5-mL portions of Dithizone Extraction Solution, draining off each extract into another separator, until the last portion of dithizone solution retains its green color. Shake the combined extracts for 30 s with 20 mL of 1 100 nitric acid, and discard the chloroform layer. Add exactly 4 mL of Ammonia-Cyanide Solution and 2 drops of Hydroxylamine Hydrochloride Solution to the acid solution. Add 10 mL of Standard Dithizone Solution, and shake the mixture for 30 s. Filter the chloroform layer through an acid-washed filter paper into a Nessler tube, and compare the color with that of a standard prepared as follows Add 0.25 mL of the Standard Lead Solution containing 10 p,g/mL of lead (Pb) ion, 4 mL of Ammonia-Cyanide Solution, and 2 drops of Hydroxylamine Hydrochloride Solution to 20 mL of 1 100 nitric acid, and shake for 30 s with 10 mL of Standard Dithizone Solution. Filter through an acid-washed filter paper into a Nessler tube. The color of the Sample Solution does not exceed that in the control. 

Lead Determine as directed under Lead Limit Test, Appendix IIIB, using 25 mL of the following solution Mix 1 g of sample with 3 mL of 1 2 nitric acid and 10 mL of water, and boil until brown fumes evolve. Add 10 mL of water, boil for 2 min, cool, and dilute to 100 mL with water. Use 100 mL of Ammonium Citrate Solution, 1 mL of Potassium Cyanide Solution, 0.5 mL of Hydroxylamine Hydrochloride Solution, and 4 xg of lead (Pb) ion in the control. 

Assay Transfer about 4 g of sample, accurately weighed, into a 250-mL volumetric flask, dissolve in and dilute to volume with water, and mix. Transfer a 25.0-mL portion of this solution into a 400-mL beaker, and add 10 mL of 1 10 hydroxylamine hydrochloride solution, 25 mL of 0.05 M disodium EDTA measured from a buret, 25 mL of ammonia-ammonium chloride buffer TS, and 5 drops of eriochrome black TS. Heat the solution to between 55° and 65°, and titrate from the buret to a blue endpoint. Each milliliter of 0.05 M disodium EDTA is equivalent to 8.450 mg of MnS04H20. Arsenic Determine as directed under Arsenic Limit Test, Appendix IIIB, using a solution of 1 g of sample in 35 mL of water. 

Aldehydes Determine as directed in the Hydroxylatnine/ Tert-Butyl Alcohol Method under Aldehydes and Ketones, Appendix VI, using about 10 g of sample, accurately weighed, and 78.13 as the equivalence factor (e) in the calculation. Allow the samples and the blank to stand at room temperature for 30 min after adding the hydroxylamine hydrochloride solution. 

Hydroxylamine Hydrochloride Solution Dissolve 50 g of hydroxylamine hydrochloride (preferably reagent grade or freshly recrystallized before using) in 90 mL of water, and dilute to 1000 mL with aldehyde-free alcohol. Adjust the solution to a pH of 3.4 with 0.5 N alcoholic potassium hydroxide. 

Procedure Transfer an accurately weighed quantity of sample, as specified in the table below, into a 125-mL Erlenmeyer flask. Add 30 mL of Hydroxylamine Hydrochloride Solution, mix thoroughly, and allow to stand at room temperature for the time specified below. Titrate with 0.5 N alcoholic potassium... 

Hydroxylamine Hydrochloride Solution Dissolve 20 g of hydroxylamine hydrochloride in sufficient water to make about 65 mL, transfer the solution into a separator, add a few drops of thymol blue TS, then add ammonium hydroxide until the solution assumes a yellow color. Add 10 mL of a 1 25 solution of sodium diethyldithiocarbamate, mix, and allow to stand for 5 min. Extract the solution with successive 10- to 15-mL portions of chloroform until a 5-mL test portion of the chloroform extract does not assume a yellow color when shaken with cupric sulfate TS. Add 2.7 N hydrochloric acid until the extracted solution is pink, adding 1 or 2 drops more of thymol blue TS if necessary, then dilute to 100 mL with water, and mix. 

Transfer 3.3 g of sample, accurately weighed, into a porcelain dish or casserole, heat on a hot plate until completely charred, then heat in a muffle furnace at 480° for 8 h or overnight, and cool. Cautiously add 5 mL of nitric acid, evaporate to dryness on a hot plate, then heat again in the muffle furnace at 480° for exactly 15 min, and cool. Extract the ash with two 10-mL portions of water, filtering each extract into a separator. Leach any insoluble material on the filter with 6 mL of Ammonium Citrate Solution, 2 mL of Hydroxylamine Hydrochloride Solution, and 5 mL of water (see Lead Limit Test, Appendix IIIB, for preparation of these solutions), adding the filtered washings to the separator. Continue as directed under Procedure in the Lead Limit Test, Appendix IIIB, beginning with Add 2 drops of phenol red TS to the separator.. .. ... 

Hydroxylamine Hydrochloride Solution Prepare as directed under Aldehydes, this Appendix. 

Procedure Weigh accurately the quantity of the sample specified in the monograph, and transfer it into a 125-mL Erlenmeyer flask. Add 30 mL of Hydroxylamine Hydrochloride Solution, and reflux on a steam bath for exactly 60 min. Allow the condenser to drain into the flask for 5 min after removing the flask from the steam bath. Detach, and rapidly cool the flask to room temperature. Add bromophenol blue TS as the indicator, and titrate with 0.5 N alcoholic potassium hydroxide to pH 3.4, or to the same light color as produced in the original hydroxylamine hydrochloride solution on adding the indicator. Calculate the mL of 0.5 N alcoholic potassium hydroxide consumed per g of sample (A). 

Approximately 200 mg of the lignin sample (Note 1), accurately weighed to the nearest 0.1 mg, is placed in a 100-ml three-necked round-bottomed flask fitted with a reflux condenser and an inlet for nitrogen. The sample is dissolved in 10 ml of 95% ethanol with addition of water if necessary. The pH of the solution is adjusted to 4.0 with dilute hydrochloric acid. The flask with the solution is placed in a constant temperature bath at 25 °C. After thermal equilibrium is attained, 40 ml of 0.05 M hydroxylamine hydrochloride solution (2 mmol) in 80% ethanol, adjusted to pH 4 with dilute hydrochloric acid (Note 2) and to a temperature of 25 °C, is added to the sample solution in the flask at reaction time zero. A stream of nitrogen saturated with ethanol (Note 3) is passed through the mixture, which is then allowed to react at 25 °C under mechanical stirring for specified reaction times up to a maximum of 30 h (Note 4). 

Colour Test. Add 2 mg to 2 ml of water and heat to dissolve add 2 ml of hydroxylamine hydrochloride solution and 2 ml of 3M sodium hydroxide, mix, and allow to stand for 30 minutes acidify with dilute hydrochloric acid and add 2 ml of a 9% ferric chloride solution—red-orange. 

HydroxamicAcidTestforNitriles(andAmides).To 1 mLofal M hydroxylamine hydrochloride solution in propylene glycol add 15 mg of the unknown dissolved in the minimum amount of propylene glycol. Then add... 

To each tube, 20 pi concentrated hydrochloric acid, 20 pi 10% hydroxylamine hydrochloride solution, 200pi ammonium acetate buffer, 80pl 0.1% 1,10-phenanthroline solution and 730 pi deionised water are added. 

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