# Methods of analysis .nilhhhhhhhhhhh

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<ul><li> 1. METHODS OF ANALYSIS For CD COMPLEXGuided By: Mrs. S.P. CHAUDHRIPrepared By: Mr. NILESH K. GAWARE Marathwada Mitra Mandalss College of Pharmacy, Pune-33 1</li></ul>
<p> 2. METHODS OF ANALYSIS There are 6 methods to analyse the cd complex. 1. 2. 3. 4.5. 6.2Method of continuous variation Spectroscopy method Distribution method pH titration methods Solubility methods General methodNILESH GAWAREMM COLLEGE OF PHARMACY. 3. 1.METHOD OF CONTINUOUS VARIATION In this we measured additive property. JOB suggested the use of additive property such asspectrophotometric extinction coefficient (dielectric constant & square of R.I) If the property for two species is different and when they are mixed no interaction is occur The value of the property is calculated by taking mean of there individual species in mixture3NILESH GAWAREMM COLLEGE OF PHARMACY. 4. If the additive property such as dielectric constant is plotted Vsmole fraction from 0-1 If there is no complex formation then it will give linear relationship.4NILESH GAWAREMM COLLEGE OF PHARMACY. 5. If the solution of two species A & B are of equal molarconc. are mix & if complex is form between them then value of additive property will pass from maximum. For a constant total conc. of A & B the complex is at highest conc. at point where the species A & B are combined in the ratio in which they occur in the complex. The line show a change in slope occurs at the mole fraction corresponding to the complex . The change in slope occur at a mole fraction indicate a type of complex .5NILESH GAWAREMM COLLEGE OF PHARMACY. 6. Spectrophotometric approach In this method measure the absorbance of the solutions ofvarious mole fraction in which the complex is form. Measure the absorbance of another same mole fraction ofsolution in which the complex is not form. Take the absorbance difference of this solutions and plot a graphVs mole fractions. Extrapolate the intersect point on x axis gives the conk . of molefraction require to form stable complex of cds.6NILESH GAWAREMM COLLEGE OF PHARMACY. 7. 7NILESH GAWAREMM COLLEGE OF PHARMACY. 8. Another relation can be used that is absorbance isproportional to the only conc. of the complex MAn,the molar ratio of ligand A to metal M and stability constant can be calculated as follows.M + nA8NILESH GAWAREMAnMM COLLEGE OF PHARMACY. 9. Log[Man]=log k + log [M]+nlog [A] where, Log[MAn]=conc. of complex Log k = equm.constant N= no. of ligand Log[M]= conc. of uncomplex metal ion In this the conc. of metal ion is kept constant while the conc. ofligand varried & corrsponding to the formation of complex is obtained from the spectrophotometric analysis. If we plot the graph of log[MAn] Vs log[A] then slope of line gives no. of ligand mole require to form complex & intercept gives the stability constant. 9NILESH GAWAREMM COLLEGE OF PHARMACY. 10. pH titration methods This is a method used in which the complexation is achieve bychange in pH. Eg.chelation of cupric ion by glycine.10NILESH GAWAREMM COLLEGE OF PHARMACY. 11. CONTINUE As the two proton are formed in the reaction of equation theaddition of glycine to a solution containing cupric ion should result in a decrease in pH . Titration curve can be obtained by adding a strong base to solution of glycine & to another solution containing glycine & cupric ion. Plot the graph of pH Vs no. of ml strong base added. The curve for glycine metal mix is well below that for the glycine alone & decreased in pH show that complexation is occur is throughout most of the neutralization range.11NILESH GAWAREMM COLLEGE OF PHARMACY. 12. 12NILESH GAWAREMM COLLEGE OF PHARMACY. 13. The results can be treated to obtain stability constant for thecomplex. The 2 successive equilibrium between the cu ion M, and glycine or ligand A, so M + A= MA k1=[MA]/ [M].[A] MA+A =MA2 k2=[MA2]/ [MA]. [A]13NILESH GAWAREMM COLLEGE OF PHARMACY. 14. M + 2A =MA2;= K1.K2=[MA2]/ [M].[2A]Where , k1 & k2=formation constant, = equilibrium constant14NILESH GAWAREMM COLLEGE OF PHARMACY. 15. The average number of ligand group bound per metal ion presentis given by The denominator gives the total conc. of metal present in in allform. 15NILESH GAWAREMM COLLEGE OF PHARMACY. 16. [MA]+ 2[MA2] =[M] + [MA] +[MA2] [M] =[MA2] =K1.K2=1/[A]2 P[A]= log n =1 P[a]=log k1 n=1/2 P[A]= log k2 n=3/216NILESH GAWAREMM COLLEGE OF PHARMACY. 17. If we know the value of n & we can determine the individualcomplex formation constant & stability constant. When graph is plotted of n Vs p[A] w.r.t to pHs17NILESH GAWAREMM COLLEGE OF PHARMACY. 18. It is seen that value of n is reach up to certain value whichindicate that maximum no of glycine mole that can combine with cu ion.18NILESH GAWAREMM COLLEGE OF PHARMACY. 19. SOLUBILITY METHOD Higuchi & Lach used this method for detection of complex. Take a container with closure system. Add drug in to thecontainer along with the solution of complexing agent. Make series of solution of different conc.of complexing agent& the bottle's are agitated in a constant temperature bath. Aliquid portion is removed & analyzed.19NILESH GAWAREMM COLLEGE OF PHARMACY. 20. In this p-amino benzoic acid(PABA) is drug & caffeine iscomplexing agent. The results of above experiments is plotted as molar conc.of PABAVs. molar conc. of caffeine. The point A at which the line crosses the vertical axis show thesolubility of drug in water. Add caffeine then observed. There is increase in solubility of PABAlinearly owing to complexion.20NILESH GAWAREMM COLLEGE OF PHARMACY. 21. 21NILESH GAWAREMM COLLEGE OF PHARMACY. 22. At point B the solution is saturated w.r.t. the complex & to the 22drug itself. The complex continue to form & precipitate from the saturated system as more caffeine is added. At point C all excess solid PABA has passed into solution & has converted to the complex. Although the solid drug is exhausted and the solution is no longer saturate some of the PABA remain uncomplexd in solution. It is further combine with caffeine to form higher complex as shown in fig.NILESH GAWAREMM COLLEGE OF PHARMACY. 23. Distribution Methods The method of distributing a solute, between twoimmiscible solvent can be used to determine the stability constant for certain compound. The complexion of iodide by Potassium iodide may be used as. E.g. To explain this method equation I2 + I-23NILESH GAWAREI3 ---MM COLLEGE OF PHARMACY. 24. Higuchi investigate the complexing action of caffeine, glycols onnumber of acidic drugs using this method. According to Higuchi & Zuck the reaction between caffeine & benzoic acid to form the B.A caffeine complexK= [B.A - caffeine]/ [B.A - caffeine] K=37.524NILESH GAWAREat 0MM COLLEGE OF PHARMACY. 25. SPECTROSCOPY & CHARGE TRANSFER COMPLEXATION It is used for charge transfer complexation. When iodine is analyzed in a noncomplexing solvent such asCCL4 a curve is obtained with single peak at about 520nm having violet color. A solution of iodine in benzene exhibits a max. shift to 475nm & peak considerably intensity for the charge shifted band appears at 300nm. A solution of iodine in diethyl ether shows a still greater shift to lower wavelength & the appearance of a new max. solution is red to brown. 25NILESH GAWAREMM COLLEGE OF PHARMACY. 26. In benzene & ether iodine is electrons accepter accepter & the 26organic solvent is donor in in ccl4;no complex is formed. The shift towards the u.v. region becomes greater as the electron donor solvents becomes a strong electron releasing agents. This spectra arise from the transfer of an electron from donor to the accepter in close contact contact in the in the excited state of the complex. The more easily a donor release its electrons as measured by its ionization potential, the stronger it is as a donor. Ionization potential of a series of donor produce a straight line, when plotted against the charge transfer energy for solution of iodine in the donor solvent.NILESH GAWAREMM COLLEGE OF PHARMACY. 27. The complexation constant K can be obtained by useof UV spectroscopy. The association between the donor D & accepter A is given as K1 D + A DA K-1 Where, k1/k-1 = equilibrium constants for complexation k1& k-1 =interaction rate constant.27NILESH GAWAREMM COLLEGE OF PHARMACY. 28. The Benesi-Hildebrand eq.given relation of k that is.A0/A=1/+1/K *1/D0 A0&D0 = initial conc. in mole/lit. = molar .absorptivity of the charge transfer complex. K= stability constant L/mole28NILESH GAWAREMM COLLEGE OF PHARMACY. 29. result in a straight line with slope of 1/K is observe A plot of A0/A Vs 1/D029NILESH GAWAREMM COLLEGE OF PHARMACY. 30. GENERAL METHODS It include Nuclear magnetic resonance ,infra redspectroscopy, polarography x-ray diffraction , kinetics etc & many more. NMR SPECTROSCOPY ; EG.complexation of caffeine with tryptophan in aq.solution was given by Nishijo et.al using H1 NMR Caffeine interacts with L-tryptophan at a molar ratio of1:1 by parallel stacking30NILESH GAWARE MM COLLEGE OF PHARMACY. 31. 31NILESH GAWARE MM COLLEGE OF PHARMACY. 32. 32NILESH GAWARE MM COLLEGE OF PHARMACY. 33. 33NILESH GAWARE MM COLLEGE OF PHARMACY.</p>