Pharmacuetical Analysis lecture notes

Introduction to phamacuetical analysis lecture notes.

1. Pharmaceutical Analysis I 1 Deneke A. ( MSc, AAU) 5/7/2023

2. 1 . Introduction Pharmaceutical Analysis : A branch of pure Chemistry that involves: Separation and purification of each substance in the sample Identification of substance or drug Determine the structure of chemical compounds Determine/quantify the relative amounts of substance in a pharmaceutical samples 5/7/2023 Deneke A. ( MSc, AAU) 2

3. Pharmaceutical analysis : Is a science which deals with I dentification & quantification of drugs in Raw materials Dosage forms & B iological fluids. Or 3 Introd …. 5/7/2023 Deneke A. ( MSc, AAU)

4. Introd …. Pharmaceutical analysis : An applied science that insures the Safety Efficacy & Stability of pharmaceutical products by using Physical Chemical Biological pharmacological & Biopharmaceutical methods. It can also be used for Elucidation of drug entities from natural products. 4 5/7/2023 Deneke A. ( MSc, AAU)

5. Introd …. In General Analysis are classified as: Qualitative analysis and Quantitative analysis Qualitative analysis : Separation, purification and Identification one or more substance in the sample. Qualitative analysis Tests are performed T o confirm the substance is present or not and To Confirm the purity of the substance (maintain the standard ) Various Qualitative tests : Use Reagents : Solubility , evolution of gas, color change and limit test etc.. Use Instruments: Mp and Bp , Refractive index Optical rotation Light absorption etc 5/7/2023 Deneke A. ( MSc, AAU) 5 Introd ….  

6. Introd ……………… Quantitative analysis : Determine how much of the substance in a sample. indicates the amount or concentration of each substance in a sample. Quantitative analysis require : the highest accuracy, precision, and reliability use of data Qualitative information is required before a Quantitative analysis There fore, pharmaceutical analysis is defined as: the Qualitative and Quantitative analysis of an active ingredient and related compounds in the pharmaceutical product 5/7/2023 Deneke A. ( MSc, AAU) 6 Introd …  

7. Introd …. To assess any hazards associated with the drug & Take necessary correction before marketing. It is one way (and often the only way) To judge quality . Deneke A. ( MSc, AAU) 7 Why analyzing drugs? 5/7/2023

8. Introd …. Pharmaceutical analysis methods/ procedures may be used to answer the following questions : Is the identity of the drug in the formulated product correct? What is the percentage of the stated content of a drug present in a formulation? Does this formulation contain solely the active ingredient or are additional impurities present ? What is the stability of a drug in the formulation At what rate is the drug released from its formulation so that it can be absorbed by the body. 8 5/7/2023 Deneke A. ( MSc, AAU)

9. Introd …. 6 . Do the identity and purity of pure drug meet specification ? 7 . What are the concentrations of specified impurities in the pure drug? 8 . What are the concentration of drug in plasma or biological fluids ? 9 . What are the Pka value (s), partition coefficients, solubilities , and stability of a drug substances under development? 9 5/7/2023 Deneke A. ( MSc, AAU)

10. Scope of pharmaceutical analysis : Pharmaceutical industry : to Raw material control In-process control Dosage form control In pharmaceutical Industry, Pharmaceutical analyst : Estimate the purity and Quality of drugs analysis of medicinal agents and their metabolites found in animals or human body Government drug control laboratory : regulatory agencies e.g. FMHACA , FDA 10 Introd …… 5/7/2023 Deneke A. ( MSc, AAU)

11. Pharmaceutical research labs Advanced research Development of analytical method Process development Dosage form evaluation Stability studies Basic research Separation/purification Identification Determination Medicinal characterization Deneke A. ( MSc, AAU) 11 Introd ….. 5/7/2023

12. Quality control (QC)and Quality Assurance(QA) In pharmaceutical industry , quality control and assessment is required: to monitor production and assess the quality, safety and effectiveness of the products Quality control: A process that deals with batch to batch uniformity of a product check the final product has desired characters like identity, purity, potency, uniformity, safety, efficacy and stability The product meet all the legal, professional and company standards. No batch of product is released to sale of supply prior to certification by qualified person. 12 Introd … 5/7/2023 Deneke A. ( MSc, AAU)

13. Introd ……… Good manufacturing practice (GMP) GMP is incorporate with QA which: ensures products are consistently produced and controlled to the quality standards GMP is concerned with both production and Quality standards Quality assurance (QA ) It is a wide ranging concept that covers all matters: QA is not the duty of one Department unit in the company all staff members who in any way can influence product quality . QA is the totality of arrangements made with the objective: ensuring the quality of the Pharmaceutical Product for their intended use 13 5/7/2023 Deneke A. ( MSc, AAU)

14. Deneke A. ( MSc, AAU) 14 5/7/2023 Introd …………

15. Official books and other standards Books of standards for pharmaceuticals and medical devices ( pharmacopoeias & formularies ) containing specifications & procedures of tests They are collectively refereed as the drug compendia Drug compendia are sub classified as Official ( accepted by some recognized authority) & Non-official 15 5/7/2023 Deneke A. ( MSc, AAU)

16. Pharmacopoeia Pharmacopoeias are official documents that provide guidelines, specifications, and analytical procedures for various drug substances. British Pharmacopoeia (BP) United states pharmacopoeia (USP) European Pharmacopoeia Japanese pharmacopoeia Drug manufacturers must comply with these pharmacopoeias according to the regulations of different countries The International Pharmacopoeias are good sources of the specifications and standards commonly used drug substances 5/7/2023 Deneke A. ( MSc, AAU) 16

17. Pharmacopoeia 5/7/2023 Deneke A. ( MSc, AAU) 17

18. Monograph : Is a written description of the principal features of the drug and the ways that these features can be determined Contents of official Monograph Description Minimum standard of purity Identification tests Limit tests to exclude excessive impurities Physical constants Storage conditions and packaging Labeling Dosage Therapeutic category Quantitative assays 5/7/2023 Deneke A. ( MSc, AAU) 18 Pharmacopoeia…

19. Titles: Main titles Subsidiary titles or synonyms Molecular formula and molecular weights Chemical names have also been provided (IUPAC) Identification: tests for Basic and acidic radicals for inorganic chemicals . Organic substances are identified by The reactions of functional groups present in the molecule Deneke A. ( MSc, AAU) 19 Pharmacopeia.. 5/7/2023

20. Dosage: Doses mentioned in monographs are intended for general guidance Minimum standards of purity, Assay Tolerance : The range is inclusive of the two limits and values outside the range is not acceptable allow for Analytical errors Variations in manufacture and compounding, and For deterioration to an extent considered insignificant under practical conditions Deneke A. ( MSc, AAU) 20 Pharmacopeia.. 5/7/2023

21. Description: It is provided to indicate the properties of the chemicals. Solubility: are provided primarily as information. However, where quantitative solubility test is given under standards the drug should comply with all these requirements. E.g. Very soluble, Freely soluble…. Deneke A. ( MSc, AAU) 21 Pharmacopeia.. 5/7/2023

22. Packaging, storage and labeling: The container should not interact physically or chemically with the chemical Storage condition: Cold : any T O not exceeding 8 O & 2 O to 8 O C . Cool : Any T O between 8 O and 25 O C . Room Temperature : T O prevailing in working area Warm : Any T O between 20 O and 40 O C . Excessive heat : Any to above 40 O C . Deneke A. ( MSc, AAU) 22 Pharmacopeia.. 5/7/2023

23. Where no specific conditions are indicated it is to be understood that storage conditions includes protection from Moisture Freezing Excessive heat. Deneke A. ( MSc, AAU) 23 Pharmacopeia.. 5/7/2023

24. Physical constants : Are characteristic properties useful for both: identification and maintenance of standards of purity These are:- Melting point Boiling point Refractive index Optical rotation Light absorption Solubility etc.. Deneke A. ( MSc, AAU) 24 Pharmacopeia.. 5/7/2023

25. Pharmacopeia.. 5/7/2023 Deneke A. ( MSc, AAU) 25

26. 5/7/2023 Deneke A. ( MSc, AAU) 26 Pharmacopoeia

27. Chemical Purity Chemical purity can be described as complete freedom from foreign matter . A state of absolute purity (100%) is virtually unattainable . Criteria that determine the acceptable level of purity : The cost-effectiveness of the process. The purification methods. Partly on the stability of the product. Toxicity of the impurities The dose of the active ingredient 5/7/2023 Deneke A. ( MSc, AAU) 27

28. Source of Impurities in Pharmaceutical chemicals Impurities: The substances that are used in pharmaceutical field, should be almost pure so that they can be used safely It is almost impossible to get an absolutely pure material as impurities get incorporated in to them either during Isolation or purification During Manufacturing Process and Storage ( Chemical and physical instability) 28 5/7/2023 Deneke A. ( MSc, AAU)

29. Source of Impurities … Effects of impurities : Toxic effect when present above certain limit. The therapeutic effect of the drug is decreased. Change in physical and chemical properties of the sub. ( make it useless) Lower the shelf life of the substance. Changes in odor, color, taste etc. 29 5/7/2023 Deneke A. ( MSc, AAU)

30. limit Test Limit tests are quantitative test designed to identify and control small quantities of impurities present in the substance test for detecting impurities in the substances Various types of limit tests prescribed by pharmacopoeias: limit test of Limit test of metallic impurities, limit test of moisture, Limit test of ash….. Important of Limit Test : Test being used to identify the impurity Test being used to control the impurity 30 5/7/2023 Deneke A. ( MSc, AAU)

31. Methods of Analysis   There are different methods of Analysis :(Qualitative & Quantitative) The methods are classified based on: I Analyte interaction , 1. Chemical method 2. Physicochemical m ethod (Instrumental ) II Analyte quantity , a. Macro b. Semi micro c. micro and d. ultra micro III Physical states of the reactants Wet method Dry Method 5/7/2023 Deneke A. ( MSc, AAU) 31

32. Method of Analysis…. I. Classification based on analytes Interaction 1. The chemical methods ( classical methods) The Substance to be analyzed is converted into a compound having some specific properties, establish the identity of the substance. The chemical change involved is known as analytical reaction The substances responsible for this change is called a reagent Substance of a sample that is to be analyzed is called analyte Analyte + Reagent  analytical Reaction → Product 5/7/2023 Deneke A. ( MSc, AAU) 32

33. Method of Analysis…. The Chemical /classical methods of Analysis are : Qualitative and Quantitative i. Qualitative chemical method of Analysis In qualitative method of analysis the reagents are interact with analytes For separation use Group/selection Reaction and For Identification: Use individual (characteristic) reactions . 5/7/2023 Deneke A. ( MSc, AAU) 33

34. Method of Analysis…. Group/ selection reactions : use for selection/separation of substances from the sample Substances with similar properties are united Eg group reagent reaction in systematic analysis Individual/ Characteristic Reactions have the individual substance nature Gives a unique characteristic only one individual substance Uses for detection/Identifications eg specific reaction of iodine iodine with starch: complex compound blue color 5/7/2023 Deneke A. ( MSc, AAU) 34

35. Method of Analysis…. ii. Quantitative chemical method of Analysis Volumetric methods Gravimetric methods Gasometric methods 5/7/2023 Deneke A. ( MSc, AAU) 35

36. a. Volumetric methods Assay is based on The measurement of Volume of solution of known conc. through Titration Based on Volume of solution of known conc. the analyte is determined Titration: A Process of addition of a reagent solution of a known concentration to a solution of the sample to be determined until the reaction is complete . Preferred to gravimetric processes especially because of speed & convenienc e. 36 Deneke A. ( MSc, AAU) 5/7/2023 Method of Analysis….

37. depending up on the type of reactions involved in the titration There are different Volumetric method : They are: Acid -Base (Neutralization) titrations Precipitation titrations Complexometric titrations Oxidation reduction titrations 37 Deneke A. ( MSc, AAU) 5/7/2023 Method of Analysis….

38. b. Gravimetric methods Is a process of isolating and weighting the compound of known composition. Isolate the analytes and weight of a final products as, pure , stable and definite chemical structure The Gravimetric method is achieved by: Precipitation method Volatilization Method 38 Deneke A. ( MSc, AAU) B. 5/7/2023 Method of Analysis….

39. c . Gasometric methods Involve measurement of the volume of gases. They measure the : Volume of gas librated in the given chemical reaction under the conditions that are described in the process suitable agent is placed to absorb one of the gases present collect and measure the volume gases 39 Deneke A. ( MSc, AAU) 5/7/2023 Method of Analysis….

40. Method of Analysis…. 2. Physico-chemical methods (Instrumental methods ) Depends on measuring physical properties which are: useful for both identification and maintenance of standards of purity Use full for determination amount of the substance as: The measured properties q uantitatively related to conc. o f the substance to be determined They are classified as: O ptical/ light interaction (Spectroscopic method) Electrical( electrochemical method) Chromatographic method 5/7/2023 Deneke A. ( MSc, AAU) 40

41. Spectroscopic method/optical Based on measurement of the interaction between Light (EMR)and analytes measure (emitted or absorbed) light by the analytes Absorbance or Transmittance Instruments : AAS, UV-Vis AES , XFS, MS, IR, NMR Other methods uses light for measurements of physical properties measure optical activ­ity by Polarimetry measure refractive index by Refractometer 5/7/2023 Deneke A. ( MSc, AAU) 41 Method of Analysis….

42. Method of Analysis…. Electrochemical Method : involve the measurement of such electrical properties as Voltage current, resistance, and quantity of electrical charge. Instruments : Conductometry , Potentiometry , Polarography , Amperometry . Chromatographic method : used as prior to qualitative chemical method I nstrumental method of Chromatography use sophisticated instruments HPLC, GC …. Deneke A. ( MSc, AAU) 42 5/7/2023

43. Method of Analysis…. …… II. Classification based on analytes quantity Based on amount of the substance used for analysis these are: a. Macro – analysis Relatively large quantities of substances, 0.5 to1.0g of solid or 20 to 50mL of liquid samples are used . b. Semi - micro analysis : Uses 0.04 to 0.05 times the amount of sample used for macro-analysis. c. Micro - analysis : Uses 0.01 times the quantity of sample used in macro-analysis Macro-analysis > 100 mg sample Semi-micro analysis 10 – 100 mg sample Micro-analysis < 1.0 mg sample 5/7/2023 Deneke A. ( MSc, AAU) 43

44. Method of Analysis…. III  Classification based on the physical states of reactants these methods depending on the physical states of reactants. . a. dry method : the sample the reagent taken as solid states flame test : coloring of gas torch flame Spot test: analysis in drops on filter paper: arise a colored spots crush (rub) sample to powder with analytical reagent 5/7/2023 Deneke A. ( MSc, AAU) 44

45. Method of Analysis…. b . wet methods : The sample and the reagents are taken as a form of solutions by : precipitation or dissolving of precipitate; formation of colored compound or evolution of gas with specific properties ( colour , odour ) 5/7/2023 Deneke A. ( MSc, AAU) 45

46. 1.2 Steps in Chemical A nalysis 46 Deneke A. ( MSc, AAU) 5/7/2023

47. An analysis involves several steps and operations which depend on : T he particular problem Your expertise The apparatus or equipment available. The analyst should be involved in every step . The following below are the basic steps of Analysis 47 Deneke A. ( MSc, AAU) 5/7/2023 Steps of Analysis….

48. 5/7/2023 Deneke A. ( MSc, AAU) 48 Define the problem: Identify the problem Picking a Method : Select a Suitable method of Analysis Acquiring the Sample : Sampling : Obtain a representative sample Processing the sample : preparation of the sample Eliminating Interferences (Qualitative analysis ): Separation and detection Calibration and Measurement : (Quantitative Analysis) Calculating Results Evaluating Results by Estimating Their Reliability Steps of Analysis

49. 5/7/2023 Deneke A. ( MSc, AAU) 49

50. Why do samples often need pre-treatment before analysis? There are three key issues that often necessitate pre-treatment of a sample prior to analysis: The sample is in the wrong physical state for the analysis method (e.g., the method requires a liquid but you have a solid sample), The sample has interfering matrix components that may give either a false positive or negative reading in the measurement, and The sample has too low analyte concentration to be detected by the instrument. 50 Deneke A. ( MSc, AAU) 5/7/2023 Steps of Analysis…..

51. Pharmaceutical samples : Table below lists types of samples that are typically found in the pharmaceutical analytical chemistry lab. Sample type Explanation Plasma sample Metabolism or bioavailability Tablet, capsule Solid mixture Packaging material, rubber gasket, bottle Solid mixture Transdermal patch, topical gel Semisolid solution Elixir Solution Aerosol Solid in gas Oral suspension, topical lotion Solid suspended in liquid or Oral suspension, topical cream liquid–liquid suspension (emulsion) Candy lozenge Solid–Solid suspension 51 5/7/2023 Deneke A. ( MSc, AAU) Steps of Analysis

52. Primary concern for a sample preparation : - Range - Selectivity - Recovery - Stability Range : The method of Analysis must be developed before the sample preparation method. The conc of the prepared sample must be within the working conc range of the instrumental method. If the sample is too diluted or concentrated , then the sample conc. must be adjusted 52 5/7/2023 Deneke A. ( MSc, AAU) Steps of Analysis

53. Recovery : must be assessed, because the recovery determines the accuracy of the analysis . For drug substance and drug product analysis, recovery of 100% is generally required to maintain required levels of accuracy and precision . Stability : Before instrumental analysis, the analyte must be stable for a reasonable amount of time. If necessary, p H adjustment . 53 Steps of Analysis….. 5/7/2023 Deneke A. ( MSc, AAU)

54. In general, a pharmaceutical sample for analysis must be: in solution form and should have following properties : Concentration must be in the measurable range of instrument Sample should be compatible with the system Quantitative recovery (desirable) The analyte should be stable until the sample is analyzed All these makes the sample to be validate 54 Steps of Analysis 5/7/2023 Deneke A. ( MSc, AAU)

55. Validation of Analytical Result Validation determines the suitability of an analysis for providing the sought-for information and can apply to samples, to methodologies, and to data. Validation is often done by the analyst, but it can also be done by supervisory personnel. . Data validation is the final step before release of the results. This process starts with validating the sample s and methods used. Then the data are reported with statistically valid limits of uncertainty after a thorough check has been made 5/7/2023 Deneke A. ( MSc, AAU) 55 Validation

56. 56 Terms use for Validation of Analytical Results (parameters of Validation) SELECTIVITY / SPECIFICITY LINEARITY AND RANGE DETECTION LIMIT LOD ACCURACY ROBUSTNESS PRECISION SYSTEM SUITABILITY LIMIT of Quantitation LOQ 5/7/2023 Deneke A. ( MSc, AAU) RUGGEDNES

57. REPEATABILITY :- Repeatability is established when the same sample is estimated repeatedly by the same analyst using same analytical method within the same laboratory using same instrument and performed within a short period of time REPRODUCIBILITY:- When a method is standardized, the test is carried out in different laboratories using the same method , the precision between the laboratories is referred to as reproducibility RSD%<= 1.5 or 2% 5/7/2023 Deneke A. ( MSc, AAU) 57 Terms ….

58. Terms…. Selectivity A measure of how capable it is of selecting/separating the analyte alone in the presence of other compounds contained in the sample. Sensitivity : is a measure of the ability of the method to determine low concentrations of certain analyte SPECIFICITY :- Specificity is the ability of a test method to measure the analyte explicity in the presence of other components ROBUSTNESS : refer to how resistant the precision and accuracy of an assay to small variations in the method, e.g. changes of instrumentations, slight variations in extract procedures RSD% <=2% 5/7/2023 Deneke A. ( MSc, AAU) 58

59. Limit of Detection LOD Lowest amount of analyte in a sample that can be detected but not necessarily quantitated. 59 Limit of Quantification LOQ Lowest amount of analyte in a sample that can be quantified with suitable accuracy & precision. Deneke A. ( MSc, AAU) 5/7/2023 Terms……

60. Ruggedness Degree of reproducibility of test results under a variety of conditions Different Laboratories Different Analysts Different Instruments Different Reagents Different Days Expressed as %RSD <= 2% 60 Deneke A. ( MSc, AAU) 5/7/2023 Terms……

61. Precision : is defined as the agreement between two or more measurements of the same quantity that have been made in an identical fashion . Precision describes the reproducibility of results . We can determine precision just by measuring replicate samples Precision can be reported by standard deviation (s), variance (V) and coefficient of variation (Relative Standard Deviation ) (RSD ) 61 5/7/2023 Deneke A. ( MSc, AAU) Terms……

62. Stastical evaluation of analytical Data 1. Mean Mean value ( µ) refers to the numerical value obtained by dividing the sum of all measurements by the number of measurements. Mean ( µ) = ∑(x i )/n Example: calculate the mean value for the data 10.06, 10.20, 10.08, 10.10. Mean ( µ) = (10.06 + 10.20+ 10.08+10.10)/4 = 10.11 Note : The mean value may or may not be in the measured values. Deneke A. ( MSc, AAU) 62 5/7/2023 Terms…..

63. 2. Deviation from Mean or Median   It is the numerical difference with out regard of sign, between a particular value and mean. Dv from the mean = (x i – µ ) Example: In the above example Mean ( µ )= 10.06 Deviation from the mean  10.11 - 10.06  0.05 3. Average deviation from the Mean Average deviation from the mean is obtained by dividing the sum of the deviations from the mean by the number of measurements . Av.deviation from the Mean ( AvdM ) = ∑ (x i – µ ) / n From the above example : Mean ( µ ) = 24.29 Average deviation from the mean  (0.10+0.09+0.01) / 3  0.07 Note : If the deviations from the mean are large results are less precise and if small more precise are the results 5/7/2023 Deneke A. ( MSc, AAU) 63 Terms……

64. 64 64 4. Standard deviation (SD ) Is a measure of precision. It is given by the formula s = √ ∑ (x i -µ) 2 N xi - individual measurment µ - mean value of infinite number of measurements N - total number of measurements (large number of measurments ) If the number of measurements is limited s = √ ∑ (x i -µ) 2 N-1 5. Relative standard deviation (RSD) (coefficient of Variance) R. S.D expressed relative to the mean and usually expressed as a percentage(R.S.D) The analytical method is considered precise if the RSD% equal to or below 1.5 %. 64 5/7/2023 Deneke A. ( MSc, AAU) Terms….

65. Example: Estimate the standard deviation, s, for the following data : 4.28, 4.21, 4.30, 4.36, 4.26, and 4.33. Mean = (4.28 + 4.21 + 4.30 + 4.36 + 4.26 + 4.33)/ 6 = 4.29 With ∑d 2 = ∑(X i - µ ) 2 = 0.0140 Standard deviation s = √∑ (x i -µ) 2 =√ 0.0140 / 6-1 =√ 0.0140 / 5= 0.053 N-1 RSD %= ? 65 X i d,(X i -X) d 2 , (X i -X) 2 4.28 0.01 0.0001 4.21 0.08 0.0064 4.30 0.01 0.0001 4.36 0.07 0.0049 4.26 0.03 0.0009 4.33 0.06 0.0036 5/7/2023 Deneke A. ( MSc, AAU) Terms……

66. Example: The following data has been obtained for the analysis of copper: 17.92, 18.04, 17.95, 17.98, 18.06. µ (Mean) = 17.99 a. Calculate the Average Deviation from the mean b. standard deviation and the relative standard deviation What do you conclude about precision of the data 66 5/7/2023 Deneke A. ( MSc, AAU) Terms……

67. 6. Variance is simply the square of standard deviation. Variance has additive property. The overall variance is the sum of the variances of individual steps. Extraction of the square root yields an estimate of the standard deviation for the overall process. S 2 = V = S 1 2 + S 2 2 + S 3 2 S = √V = √S 2 67 5/7/2023 Deneke A. ( MSc, AAU) Terms……

68. Accuracy: I ndicates the closeness of the measurement to the true or accepted value. Accuracy measures agreement between a result and the accepted /truth value. But Precision describes the agreement among several results obtained in the same way Accuracy is often more difficult to determine because the true value is usually unknown. An accepted value must be used instead. Accuracy is expressed in terms of error . Error, E, is deviation from the accepted (true)value. The required accuracy is a bias of ≤ 2% for dosage forms and ≤ 1% for drug substance 68 5/7/2023 Deneke A. ( MSc, AAU) Terms……

69. 5/7/2023 Deneke A. ( MSc, AAU) 69 Terms……

70. Errors in Analytical Results The terminology ‘ error’ refers to the difference between a measured value and the accepted or truth value . absolute error E : is the difference between the measured value and the truth value . Absolute Error, E = where is the measured value, is the truth vlue The sign of the absolute error tells you whether the value in question is high or low. If the measurement result is low, the sign is negative; if the measurement result is high, the sign is positive.   70 5/7/2023 Deneke A. ( MSc, AAU)

71. Errors…… Relative Error Er is a more useful quantity than Absolute Error The percent relative error is given by the expression X 100 where truth value = measured mean value Exercise Types of Errors Errors have been broadly classified into two major categories 1. Determinate Error(systematic) 2. Indeterminate error(random)   5/7/2023 Deneke A. ( MSc, AAU) 71

72. I . Determinate Error Errors that cause the measured value for each measurement to be changed uniformly in one particular direction by one particular amount Have a definite value(one direction error ) errors whose magnitude can be determined. It can be corrected or avoided 5/7/2023 Deneke A. ( MSc, AAU) 72 Errors….

73. Errors … II Indeterminate Error Errors that cause the measured value for each measurement to be scattered randomly errors whose magnitude can not be determined. It can not be avoided or corrected. Determinant errors subdivided into 3 groups,. Personal , Instrumental and Errors of Method. 73 5/7/2023 Deneke A. ( MSc, AAU)

74. Errors…. A. Personal Error These errors are due to the factor for which the analyst is responsible. origin in lack of skill and experience, carelessness and other personal limitations of the experimenter. The common sources of errors are - handling of hygroscopic substances, improper transfer of precipitates and reading the beam balance. Personal errors can be totally avoided by taking more care during the analysis 5/7/2023 Deneke A. ( MSc, AAU) 74

75. Errors…  b. Instrumental Error These errors are associated with the instruments being used for analysis. These errors arise from imperfection of instruments and the use of uncalibrated or improperly calibrated apparatus and instruments. Instrumental errors can be avoided by using perfectly and properly calibrated instruments. 75 5/7/2023 Deneke A. ( MSc, AAU)

76. Errors… C . Errors of Method Analytical procedures are also subject to limitations which give rise to errors that can be traced to the method Arise from non ideal chemicals or physical behavior of analytical system Example , incompleteness of reaction , instability of species, non- specificity of most reagents. Error inherent in a methods are often difficult to detect and the most serious of the systemic error 76 5/7/2023 Deneke A. ( MSc, AAU)

77. Detection of Determinate Errors I nstrumenta l errors can be easily detected and eliminated by the use of calibrated instruments and apparatus. It is easier to detect compared to the Personal. Er . and Method Er . Personal Errors and Method Errors are very difficult to detect but there are methods to detect these errors 5/7/2023 Deneke A. ( MSc, AAU) 77 Errors…

78. Deneke A. ( MSc, AAU) 78 Systemic and Random can be distinguished in the following example 5/7/2023 Errors…

79. 5/7/2023 Deneke A. ( MSc, AAU) 79 Errors…

80. Student 1 Found a mean which is very close to the true value Precise and accurate No random Errors and Systematic Errors The analysis procedure is done carefully Student 2 closely clustered results but a mean which is less than the true value Precise but not completely accurate No random errors but systematic errors Random errors lead to the production of scattered measurements and systematic errors lead to a mean which is not close to the true value 5/7/2023 Deneke A. ( MSc, AAU) 80 Errors………….

81. 5/7/2023 Deneke A. ( MSc, AAU) 81 The following are factors giving rise to Errors and in an assay, Identify the type of errors produce and if the error is systematic then specify (Method , personal or method) Errors…

82. . . Deneke A. ( MSc, AAU) 82 2.2 Basic calculations in pharmaceutical analysis 5/7/2023

83. Basic calculation in Analysis Units of Concentration 1. Molecular weight( Mwt ) or Molcular mass of a compound (MM) the sum of the atomic weights of all the atoms in a compound. Example Mwt of NaOH is 40 grams where the atomic weights are as follows: Na = 23, O = 16, and H = 1. MWt of NaOH would be 40 grams, and so forth. 2 . A mole is molecular weight of a substance . Example one mole of NaOH is mwt of NaOH = 40 grams A half mole NaOH (0.5 mole) is 20 grams N o of mole (n) = Given weight/ Mwt or N o of mole (n ) = Given mass/MM 5/7/2023 Deneke A. ( MSc, AAU) 83

84. Basic calculation in Analysis……. 3. Molarity( Molar concentration) Molarity (M) is the number of moles present in one liter of solution The molar concentration ( C x ) of the solution of the chemical species X is the number of moles of that species that is contained in one liter of the solution (not one liter of the solvent ). The unit of molar concentration is molarity, M,( mol L -1 ) C x = n o mole solute n o L solution Molar solutions may have as a solute a solid, a liquid, or a gas 5/7/2023 Deneke A. ( MSc, AAU) 84

85. 85 Calculating Molarity 5/7/2023 Deneke A. ( MSc, AAU) Basic calculation in Analysis…….

86. Basic calculation in Analysis…….   Example 2 Describe the preparation of 5.0L of 0.1mol/LNa2CO 3 (105.99 g/ mol ) from the primary standard solid. Solution: F ind the no of moles NaCO3 then find the Mass required Step1 Mole of Na2CO 3 C Na 2 CO 3 = no of mole Na 2 CO 3 Vol Na2CO3 (L) No of mol(n) Na 2 C O 3 = 0.1 mol/L X 5.0L = 0.5mol Step 2 Mass of Na 2 CO 3 Mass Na 2 CO 3 = 0.5mol Na 2 CO 3 X 105.99 g/ mol Na 2 CO 3 ans = 53.00g Na 2 CO 3 Dissolve 53.00g of Na 2 CO 3 in water dilute it to 5.0L. 86 5/7/2023 Deneke A. ( MSc, AAU)

87. Basic calculation in Analysis……. Example:3 Calculate the molar concentration of ethanol in an aqueous solution that contains 2.30g of C 2 H 5 OH (46.07 g/mol/ in 3.50L of solution. sol n : - conversion of the no of grams of ethanol to the corresponding number of moles. Step 1 . Amount C 2 H 5 OH ( in mol ) n = 2.30g C2H5OH 46.07g/ mol C 2 H 5 OH Step2. then calculate Molar concentration of Ethanol : C2H5OH (M) = 0.04992mol = 0.0143molL -1 = 0.0143M 3.50L 87 5/7/2023 Deneke A. ( MSc, AAU)

88. Basic calculation in Analysis……. Exercise 1. What is the Molarity of a solution containing 29.25 grams of sodium chloride in 500 ml. of total solution? MWt of NaCl =58.5 g/mole 2. Describe the preparation of 2.00L of 0.108M BaCl2 from BaCl2.2H2O. Given MWt . Of BaCl2.2H2O = 244.3g/ mol ( Answer 52.8g ) 5/7/2023 Deneke A. ( MSc, AAU) 88

89. 89 5/7/2023 Deneke A. ( MSc, AAU) Basic calculation in Analysis……. 4

90. Basic calculation in Analysis……. 5. Percentage composition of substances Percent composition of a solution can be expressed as: 5.1 Weight percent (w/w ) = mass of solute X 100% mass of sol n   5.2 Volume percent (v/v ) = volume of solute X 100% volume of solution 5.3 Weight /volume percent (w/v) = mass of solute g X 100% volume sol n 90 5/7/2023 Deneke A. ( MSc, AAU)

91. Weight percent(W/W) is frequently employed to express the concentration of commercial aqueous reagents. E.g. 37% hydrochloric solution – this means the reagent contains 37g of HCl per 100g of solution. 91 5/7/2023 Deneke A. ( MSc, AAU) Basic calculation in Analysis…….

92. Volume percent (V/V) is commonly used to specify the concentration of a solution prepared by diluting a pure liquid with another liquid. E.g. 5% aqueous solution of methanol prepared by diluting 5.0ml of pure methanol to give 100ml of solution with enough water 92 5/7/2023 Deneke A. ( MSc, AAU) Basic calculation in Analysis…….

93. Weight /volume percent(W/V) indicate the composition of dilute aqueous solutions of solid reagents e.g 5% aqueous silver nitrate: prepared by dissolving 5g of silver nitrate add enough water to give 100ml of solution.   93 5/7/2023 Deneke A. ( MSc, AAU) Basic calculation in Analysis…….

94. Basic calculation in Analysis……. Relation of Molarity and Percentage of substances M = density * % * 10 or Mwt M= specific gravity * % * 10 Mwt . The density of a substance is its mass per unit volume whereas Specific gravity is the ratio of its mass to the mass of an equal volume of water at a specified temperature (ordinarily 4 O C ). Unit of density is kg/L or mg. /ml. Specific gravity is dimensionless. 5/7/2023 Deneke A. ( MSc, AAU) 94

95. Example 1: Calculate the molar concentration of H2SO4 (98.0g/mol) in a solution that has a specific gravity of 1.82 and is a 98% H2SO4 (w/w)   M= specific gravity * % * 10 Mwt of H2SO4 = 1.82 *98% *10 = 18 M 98 gram/mol 95 5/7/2023 Deneke A. ( MSc, AAU) Basic calculation in Analysis…….

96. Exercise Calculate the molar concentration of HCl that has specific gravity of 1.18 and is 37% (w/w) HCl (36.5g/ mol ) Ans HCl = 12M 5/7/2023 Deneke A. ( MSc, AAU) 96 Basic calculation in Analysis…….

97. Parts per million & parts per billion (PPM) For very dilute solution PPM is convenient way to express concentration: C ppm X 10 6 ppm Where C ppm is the concentration in parts per million. The units of mass in the numerator & denominator must agree. For even more dilute solutions we use parts per billion( PPb ) C ppb = Mass of solute X10 9 ppb Mass of solution N.B 1ppm= 1mg/L 97 Deneke A. ( MSc, AAU) Basic calculation in Analysis ……. 5/7/2023

98. Basic calculation in Analysis……. Exercise What is the molarity of K + in aqueous solution that contains 63.3 ppm. k 3 Fe (CN) 6 (329.2 g/mol)? mmol K + = 3*mass k 3 Fe (CN) 6 = 3*63.3mg = 0.576mmol milmolar mass k 3 Fe (CN) 6 329.2mg/ mol M= nmol /L = 0.5768 * 10 -3 mol L -1 Answer: Molarity of K + = 5.77X10 -4 mol L -1 hint Cppm = mass solute (mg) Volume of sol n in liter (L ) 98 5/7/2023 Deneke A. ( MSc, AAU)

99. Basic calculation in Analysis……. Exercise The maximum allowed concentration of chloride in a municipal drinking water supply is 2.50 × 102 ppm Cl–. When the supply of water exceeds this limit, it often has a distinctive salty taste. What is this concentration in moles Cl–/ liter ( mlar conc.)? 5/7/2023 99 Deneke A. ( MSc, AAU)

100. Dilution solution from the stock the following useful relationship V con X C can = V dil C dil where Where: Vconc = Volume of conc sol n C conc = Con cof the orignal sol n Vdi = Vol. of d iluted sol n to be prepared Cdil = concentration of dil. sol n 100 Basic calculation in Analysis……. 5/7/2023 Deneke A. ( MSc, AAU)

101. Basic calculation in Analysis ……. Example: How would you prepare 50.0ml portions of standard solution that are: a. 0.05M, b 0.002M from 0.1M standard solution of Na2CO3 . V concd C concd = V dil C dil : the no of mil. moles of Na2CO3 taken from the stock(conc.) sol n must equal to the no of mol in the diluted sol n Ans a. V concd = V dil C dil : + C dil sol n = 50ml X 0.05m mol Na + /ml = 25ml: 0.1m mol Na + /ml Take 25ml from the stock and dilute to 50ml to get b.? 101 5/7/2023 Deneke A. ( MSc, AAU)

102. Summary : Some useful Algebraic Relationship For a chemical species A Amount A ( mmol ) = mass A (g) millimolar mass A (g/ mmol )   Amount A (mol) = mass A (g) molar mass A(g/mol) Amount A ( mmol ) = V (ml) X C A ( mmolA /ml) Amount A (mol) = V (L) X C A (mol A/L) Where V is the volume of the solution , milimolar mass is Mwt . 102 Basic a calculation analysis……. 5/7/2023 Deneke A. ( MSc, AAU)