2.3. IDENTIFICATION - DrugFuture

1 EUROPEAN PHARMACOPOEIA IDENTIFICATION reactions of ions and functional IDENTIFICATION01/2008 IDENTIFICATION REACTIONS OFIONS AND FUNCTIONAL GROUPSACETATESa) Heat the substance to be examined with an equal quantity ofoxalic acid R. Acid vapours with the characteristic odour ofacetic acid are liberated, showing an acid reaction ( ).b) Dissolve about 30 mg of the substance to be examined in3mLofwater Ror use 3 mL of the prescribed solution. Addsuccessively mL oflanthanum nitrate solution R, M iodineand mL ofdilute ammonia to boiling.

2 Within a few minutes a blue precipitate isformed or a dark blue colour a test-tube about 180 mm long and 18 mm in externaldiameter, place about 15 mg of the substance to be examined,ortheprescribedquantity, acid the tube with a stopper through which passes a smalltest-tube about 100 mm long and 10 mm in external diametercontainingwater Rto act as a condenser. On the outside ofthe smaller tube, hang a drop oflanthanum nitrate solution for substances hydrolysable only with difficulty, place theapparatus in a water-bath for 5 min, then take out the smallertube.

3 Remove the drop and mix it with mL M iodineon a tile. Add at the edge mL ofdilute ammonia min to 2 min, a blue colour develops at the junction of the twodrops; the colour intensifies and persists for a short hydrolysable only with difficultyheat themixture slowly to boiling over an open flame and then proceedas prescribed a few milligrams of the substance to be examined,or the prescribed quantity, in 5 mL ofwater R,adddilutehydrochloric acid Runtil an acid reaction occurs ( ), then1mLofpotassium iodobismuthate solution precipitate is formed about 15 mg of the substance to be examined in2mLofwater Ror use 2 mL of the prescribed solution.

4 Addabout mL ofdilute hydrochloric acid Rand about mLofthioacetamide reagent sodium hydroxide solution precipitate is formed which dissolves on furtheraddition ofdilute sodium hydroxide solution chloride solution is , PRIMARY AROMATICA cidify the prescribed solution withdilute hydrochloric acid Rand add mL ofsodium nitrite solution ,add1mLof -naphthol solution red colour and usually a precipitate of the same colour SALTSTo the prescribed solution add g ofmagnesium oxide a current of air through the mixture and direct the gasthat escapes just beneath the surface of a mixture of 1 mL M hydrochloric acidand mL ofmethyl red solution colour of the indicator changes to yellow.

5 On additionof 1 mL of a freshly prepared 100 g/L solution ofsodiumcobaltinitrite Ra yellow precipitate is SALTS AND SALTS OF VOLATILE BASESD issolve about 20 mg of the substance to be examined in 2 mLofwater Ror use 2 mL of the prescribed solution. Add 2 mL ofdilute sodium hydroxide solution ,thesolutiongives off vapour that can be identified by its odour and by itsalkaline reaction ( ).ANTIMONYD issolve with gentle heating about 10 mg of the substance to beexamined in a solution of g ofsodium potassium tartrate Rin 10 mL ofwater Rand allow to cool: to 2 mL of this solution,or to 2 mL of the prescribed solution, addsodium sulfidesolution Rdropwise.

6 An orange-red precipitate is formed whichdissolves on addition ofdilute sodium hydroxide solution 5 mL of the prescribed solution on a water-bath withan equal volume ofhypophosphorous reagent is , NON-NITROGEN SUBSTITUTEDD issolve about 5 mg of the substance to be examined in 3 mLofmethanol R, add mL of a solution containing 100 g/Lofcobalt nitrate Rand 100 g/L ofcalcium chloride add, with shaking, mL ofdilute sodium hydroxidesolution R. A violet-blue colour and precipitate are ) To 1 mL of the prescribed solution add mL offerricchloride solution R1.

7 A dull-yellow precipitate, soluble inether R, is ) ,treatedifnecessary as prescribed, in a test-tube. Moisten with mL mL ofsulfuric acid R. Gently warm the bottom of the white sublimate is deposited on the inner wall of the ) Dissolve g of the substance to be examined in 10 mLofwater Ror use 10 mL of the prescribed solution. mL ofhydrochloric acid R. The precipitate obtained, aftercrystallisation from warmwater Rand dryingin vacuo,hasamelting point ( )of120 Cto124 ) To g of the substance to be examined add 10 mL ofdilutehydrochloric acid Ror use 10 mL of the prescribed to boiling for 1 min.

8 Cool and filter if necessary. To1mLofthesolutionobtainedadd20mLofwater slightly yellow precipitate is formed which on addition mL to mL ofsodium sulfide solution Rturns )Toabout45mgofthesubstancetobeexaminedad d10mLofdilute nitric acid Ror use 10 mL of the prescribed for 1 min. Allow to cool and filter if necessary. To 5 mLof the solution obtained add 2 mL of a 100 g/L solution ofthiourea R. A yellowish-orange colour or an orange precipitateis formed. Add 4 mL of a 25 g/L solution ofsodium fluoride solution is not decolorised within 30 ) Dissolve in 2 mL ofwater Ra quantity of the substanceto be examined equivalent to about 3 mg of bromide (Br )oruse 2 mL of the prescribed solution.

9 Acidify withdilute nitricacid Rand add mL ofsilver nitrate solution to stand. A curdled, pale yellow precipitate is and wash the precipitate with three quantities, eachof 1 mL, ofwater R. Carry out this operation rapidly in subduedlight disregarding the fact that the supernatant solution maynot become perfectly clear. Suspend the precipitate obtained in2mLofwater Rand add mL ofammonia R. The precipitatedissolves with ) Introduce into a small test-tube a quantity of the substance tobe examined equivalent to about 5 mg of bromide (Br )ortheprescribed quantity.

10 Add mL ofwater R,about75mgoflead dioxide R, acid Rand shake gently. DryGeneral Notices (1) apply to all monographs and other IDENTIFICATION reactionsofionsandfunctionalgroupsEUROPE AN PHARMACOPOEIA and allow to stand for 5 min. Prepare a strip of suitablefilter paper of appropriate size. Impregnate it by capillarity, bydipping the tip in a drop ofdecolorised fuchsin solution Rand introduce the impregnated part immediately into the from the tip, a violet colour appears within 10 s thatis clearly distinguishable from the red colour of fuchsin, whichmay be visible on a small area at the top of the impregnatedpart of the paper ) To mL of a neutral solution containing a quantity of thesubstance to be examined equivalent to about mg of calcium(Ca2+)