EUROPEAN PHARMACOPOEIA 6.0 2.5.9.Determination of nitrogen by sulphuric acid
金嗓开音胶囊digestion Depending on the volume of 0.01M sodium thiosulphate ud,it may be necessary to titrate with 0.1M sodium thiosulphate .
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NOTE :there is a 15s to 30s delay in neutralising the starch indicator for peroxide values of 70and greater,due to the tendency of trimethylpentane to float on the surface of the aqueous medium and the time necessary to adequately mix the solvent and the aqueous titrant,thus liberating the last traces of iodine.It is recommended to u 0.1M sodium thiosulphate for peroxide values greater than 150.A small amount (0.5per cent to 1.0per cent (m/m ))of high HLB emulsifier (for example polysorbate 60)may be added to the mixture to retard the pha paration and decrea the time lag in the liberation of iodine.Carry out a blank determination (V 0ml).If the result of the blank determination exce
eds 0.1ml of titration reagent,replace the impure reagents and repeat the determination.c =concentration of the sodium thiosulphate solution in moles,per litre.01/2008:205062.5.6.SAPONIFICATION VALUE
咏柳唐贺知章>行政关系介绍信The saponification value I S is the number that express in milligrams the quantity of potassium hydroxide required to neutrali the free acids and to saponify the esters prent in 1g of the substance.Unless otherwi prescribed,u the quantities indicated in Table 2.5.6.-1for the determination.Table 2.5.6.-1
Presumed value I S关月
Quantity of sample (g)<3
203to 10
疏忽的近义词12to 1510to 40
8to 1240to 60
纳税证明在哪里开5to 860to 100
3to 5100to 200
2.5to 3200to 300
鬼门开
1to 2300to 4000.5to 1Introduce the prescribed quantity of the substance to be examined (m g)into a 250ml borosilicate glass flask fitted with a reflux condenr.Add 25.0ml of 0.5M alcoholic potassium hydroxide and a few glass beads.Attach the condenr and heat under reflux for 30min,unless otherwi prescribed.Add 1ml of phenolphthalein solution R1and titrate immediately (while still hot)with 0.5M hydrochloric acid (n 1ml of 0.5M hydrochloric acid ).Carry out a blank test under the same conditions (n 2ml of 0.5M hydrochloric acid ).01/2008:205072.5.7.UNSAPONIFIABLE MATTER The term “unsaponifiable matter”is applied to the substances non-volatile at 100-105°C obtained by extraction with an organic solvent from the substance to be examined after it has been saponified.The result is calculated as per cent m/m .U ungread ground-glass glassware .Introduce the prescribed quantity of the substance to be examined (m g)into a 250ml flask fitted with a reflux condenr.Add 50ml of 2M alcoholic potassium hydroxide R and heat on a water-bath for 1h,swirling frequently.Cool to a temperature below 25°C and transfer the contents of the flask to a parating funnel with the aid of 100ml of water R .Shake the liquid carefully with 3quantities,each of 100ml,of peroxide-free ether R .Combine the ether layers in another parating funnel containing 40
ml of water R ,shake gently for a few minutes,allow to parate and reject the aqueous pha.Wash the ether pha with 2quantities,each of 40ml,of water R then wash successively with 40ml of a 30g/l solution of potassium hydroxide R and 40ml of water R ;repeat this procedure 3times.Wash the ether pha veral times,each with 40ml of water R ,until the aqueous pha is no longer alkaline to phenolphthalein.Transfer the ether pha to a tared flask,washing the parating funnel with peroxide-free ether R .
Distil off the ether with suitable precautions and add 6ml of acetone R to the residue.Carefully remove the solvent in a current of air.Dry to constant mass at 100-105°C.Allow to cool in a desiccator and weigh (a g).Dissolve the residue in 20ml of alcohol R ,previously neutralid to phenolphthalein solution R and titrate with 0.1M ethanolic sodium hydroxide .If the volume of 0.1M ethanolic sodium hydroxide ud is greater than 0.2ml,the paration of the layers has been incomplete;the residue weighed cannot be considered as “unsaponifiable matter”.In ca of doubt,the test must be repeated.01/2008:205082.5.8.DETERMINATION OF PRIMARY AROMATIC AMINO-NITROGEN Dissolve the prescribed quantity of the substance to be examined in 50ml of dilute hydrochloric acid R or in another prescribed solvent and add 3g of potassium bromide R .Cool in ice-water and titrate by slowly adding 0.1M sodium nitrite with constant stirring.Determine the end-point electrometrically or by the u of the prescribed indicator.
01/2008:205092.5.9.DETERMINATION OF NITROGEN BY SULPHURIC ACID DIGESTION
SEMI-MICRO METHOD Place a quantity of the substance to be examined (m g)containing about 2mg of nitrogen in a combustion flask,add 4g of a powdered mixture of 100g of dipotassium sulphate R ,5g of copper sulphate R and 2.5g of lenium R ,General Notices (1)apply to all monographs and other texts 139
