Nessler cylinders

B. Duplication method. This is usually applied as the so-called colorimetric titration in which a known volume (x mL) of the test solution is treated in a Nessler cylinder with a measured volume (y mL) of appropriate reagent so that a colour is developed. Distilled water (x mL) is placed in a second Nessler cylinder together with y mL of reagent. A standard solution of the substance under test is now added to the second cylinder from a microburette until the colour developed matches that in the first tube the concentration of the test solution can then be calculated. The standard solution should be of such concentration that it amounts to no more than 2 per cent of the final solution. This method is only approximate but has the merit that only the simplest apparatus is required it will not be discussed further. 

It is advisable, wherever possible, to make a preliminary determination of the concentration of the unknown solution by adding from a burette a solution of the component in known concentration to a Nessler tube containing the reagents diluted with a suitable amount of water until the depth of colour obtained is practically the same as that of an equal volume of the unknown solution also contained in a Nessler cylinder and standing at its side. A series of standards on either side of this concentration is then prepared. 

Equipment Nessler Cylinders (or Nessler Glasses) According to the British Standard Specification No 612, 966—a pair of cylinders made of the same glass and having the same diameter with a graduation mark at the same height from the base in both cylinders (Figure 1). 

Standard Solution Into a 50 ml Nessler Cylinder, pipette 2 ml of standard lead solution and dilute with DW to 25 ml. Adjust with dilute acetic acid Sp. (IP) or dilute ammonia solution Sp. (IP) to a pH between 3.0 and 4.0, dilute with DW to about 35 ml and mix. 

Nessler cylinder 1 pair Ferric ammonium sulphate 1.726 g Sulphuric acid (0. 1 N) 10.0 ml Iron-free citric acid (20% w/v) 2.0 ml Thioglycollic acid 0.1 ml Iron-free ammonia solution 20 ml. 

Standard Colour Dilute 2.0 ml of standard iron solution with 40 ml DW in a Nessler cylinder. Add 2 ml of a 20% w/v solution of iron-free citric acid and 0.1 ml of thioglycollic acid, mix, make alkaline with iron-free ammonia solution, dilute to 50 ml with DW and allow to stand for 5 minutes. 

Materials Required Nessler cylinder 1 pair dilute nitric acid (10% w/w of HN03) 10.0 ml silver nitrate solution (5.0% w/v in DW) 1.0 ml. 

Procedure Dissolve the specified quantity for the substance in DW, or prepare a solution as directed in the text and transfer to a Nessler cylinder. Add 10 ml of dilute nitric acid, except when it is used in the preparation of the solution, dilute to 50 ml with DW, and add 1 ml of AgN03 solution. Stir immediately with a glass rod and allow to stand for 5 minutes. The opalescence produced is not greater than the standard opalescence, when viewed transversely. 

Materials Required Nessler cylinders 1 pair dilute hydrochloric acid (10% w/v of HC1) 2.0 ml. 

Materials Required Doxycyline Hydrochloride 0.30 g oxygen-combustion flask 1 L capacity Nessler cylinder 100 ml zirconyl alizarin solution 5.0ml fluoride standard solution(10ppmF)(dilute... 

Procedure Bum 0.30 g, in three equal portions, by the method for oxygen-flask combustion (BP), using a 1 Litre flask and a separate 20 ml portion of DW as the absorbing liquid for each combustion, shaking the flask vigorously for about 15 minutes and transferring to the same 100 ml Nessler cylinder. Add 5 ml of acid zirconyl alizarin solution to the combined liquids, adjust the volume to 100 ml with DW and allow to stand for 1 hour. 

Place the sample solution containing not more than 100 pg of S (as a sulphate) in a Nessler cylinder. Acidify with 2 ml of 2 M HCl, add 10 ml of ethanol and water to 40 ml, pour in quickly 5 ml of BaC solution, and stir well. After 15 min, compare the turbidity with a series of standards prepared simultaneously. The cylinders should be observed from above, against black paper, in a uniformly brightly illuminated place. 

Nessler cylinder bureta de Nessler Nessler s reagent reactivo de Nessler netilmicin netilmicina netobimin netobimina netropsin netropsina net weight peso neto... 

Into seven further 5 cm separatory funnels pipette 0.1, 0.5, 1.0, 2.0, 5.0, 7.5 and 10.0 cm of a 10 ppm toluene solution of the inhibitor which is being determined in the monomer sample (ie. additions of between 5 and 100 u g of inhibitor. Extract the sample funnel and the seven standard funnels with 20 cm distilled water then two 10 cm portions of distilled water and collect the 40 cm aqueous extracts in 50 cm Nessler cylinders (filtering if necessary). Dilute to 50 cm with water. To the sample and standard solutions add 2 cm sodium phosphotungstate reagent and 4 cm of sodium carbonate (10%) in this order and mix well after the addition of each reagent. Leave the solutions for 15 min and compare the depth of the blue colour obtained for the sample with that obtained from the various standard solutions. If necessary, repeat the run this time more closely bracketing the sample solution with the standards to obtain a better colour match between sample and standards. 

Dissolve 1 g of salicylic acid in 60 ml of ethanol, adjust the volume to 100 ml with water dilute 10 ml of this solution to 1 litre as a standard, making 1 ml = 0-1 mg of acid. Dissolve 0-6 g of aspirin in a measuring cylinder in 9 ml of ethanol and dilute with water to 90 ml. Take two similar Nessler cylinders into one pour 60 ml of the solution, into the other the remaining 30 ml with 3 ml of ethanol and adjust to the volume of the first. There is thus a difference of 200 mg in the amount of aspirin in the two solutions. Add 1 ml of 1 per cent acid ferric ammonium sulphate solution to each, mix and match the colour by adding the standard salicylic acid solution from a burette. Each ml of standard is equivalent to 0-05 per cent of salicylic acid in the sample. 

First distil a small volume (usually 3 to 5 ml) of the sample under examination with 75 ml of industrial methylated spirit and collect 50 ml of distillate. Measure 10 ml of a 2 per cent w/v solution of j5-naphthol in 40 per cent cold potassium hydroxide solution into each of several Nessler cylinders (the success of the test depends upon the strength of the potash solution). To each cylinder add measured volumes of a... 

Titrate 50 ml of the well-mixed distillate with 0 05N sodium hydroxide in a Nessler cylinder, using methyl orange as indicator, until the colour matches that of a comparison cylinder containing water and the same amount of methyl orange. 

Transfer the remaining 100 ml of distillate to a Nessler cylinder and add an amount of 0 05N hydrochloric acid to make the total acidity equal to 5 0 ml of 0 05N acid. Prepare a control cylinder containing 5 0 ml of 0 05N hydrochloric acid and water and add to both test and control cylinders 2 ml of 0 01 per cent alizarin S solution. From a burette which can be read to 0 02 ml add to the test cylinder a solution of thorium nitrate (approximately 0 25 g per litre) until a slight pink colour persists as compared with the yellow of the control cylinder. Add an exactly similar volume of the thorium nitrate solution to the control cylinder, which then becomes more pink than the test solution. Then add slowly, from a suitable burette, standard solution of sodium fluoride (0 0221 g of NaF per litre 1 ml = 10 / g of fluorine) until the tints of... 

Visual comparison using Nessler cylinders is satisfactory. A distinct yellow colour is obtained at a concentration of 5 p.p.m. 

Dilute an aliquot of a 0 1 N hydrochloric acid solution of morphine, containing not more than 1 mg of morphine, to 20 ml with 0 1 N hydrochloric acid in a 50-ml Nessler cylinder. Add 8 ml of freshly prepared 1 per cent sodium nitrite solution and mix well. After exactly fifteen minutes add 12 ml of dilute ammonia solution, dilute to 50 ml with water and remix. Transfer an equal amount of test solution to a second Nessler cylinder, dilute to 20 ml with 0 1 N hydrochloric acid, add 5 ml of dilute ammonia solution and then add freshly prepared morphine and nitrite reagent until the colour matches the colour in the first cylinder. Repeat the colour matching after preliminary dilution of the comparison solution to give approximately the same volume at the match point. 

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