Pharmaceutical Analytical Chemistry / PHC 213

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Analytical Chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials

Analytical chemistry answer two important questions What is it ?? (Qualitative analysis) gives an indication of the identity of the chemical species in the sample How much is it ?? (quantitative analysis) determines the amount (concentration) of one or more of the components in the sample

Classification of Analytical Methods : Gravimetric method Volumetric method Instrumental methods

Gravimetric method : Gravimetric methods of analysis are based on the measurement of mass. Precipitation methods: in this method the analyte is converted to a sparingly soluble precipitate. This precipitate is then filtered, washed free of impurities, and converted to a product of known composition by suitable heat treatment, and the product is weighed. Volatilization methods: in this the analyte or its decomposition products are volatilized at a suitable temperature. The volatile product is then collected and weighed, or, alternatively, the mass of the product is determined indirectly from the loss in mass of the sample

:(Volumetric method (Titration involves the addition of a reactant to a solution being analyzed until some equivalence point is reached

Types of Titration: Acid _ base titration Precipitimetric titration Complexmetric titration Redox(oxidation-reduction) titration Titration involving precipitation at end of process is called as precipitation titration . Most of metallic halides are titrated by precipitation method Compleximetric titrations are particularly useful for the determination of a mixture of different metal ions in solution Redox titration (also called oxidation-reduction titration) is a type of titration based on a redox reaction between the analyte and titrant. Redox titration may involve the use of a redox indicator and/or a potentiometer.

Instrumental methods : Spectrophotometry used to measure the absorption of a certain color of light (specific wavelength) as it passes through a treated sample.

Chromatography

Application of Analytical Chemistry : Analytical chemistry play an important role in nearly all aspect of chemistry Medicine Industry Environmental Food and Agriculture Quality control

Application of Analytical Chemistry : In medicine, analytical chemistry is the basis for clinical laboratory tests which help the physicians diagnose disease In industry, analytical chemistry provides the means of testing the raw materials for assuring the quality of finished products whose chemical composition is critical (eg. Drugs ) Foods analysis for contaminants (pesticide residues) diseases diagnosed (Blood glucose must be monitored in diabetics) Quality of manufactured products The purity of the drugs

The nutritional value of food determined by chemical analysis for major component such as protein and carbohydrate and trace components such as vitamins and minirals

Definition of some terms : Sample: is a material that we wish to analyze Analyte: is the substance or element in the sample whose presence or concentration we wish to determine titrant: is a solution of known concentration which is added (titrated) to another solution to determine the concentration of second chemical species

Titration: is a process which is performed by slow addition of standard solution "titrant" from a burette to a solution of the analyte until the reaction between the two is complete.

Standard Solution: - is a solution of known concentration - prepared by dissolving a known amount of the substance (primary standard substance)in a known volume of liquid - They provide a reference to determine unknown concentrations -Two types,, primary and secondary standard solution

Standard solution Secondary standard Primary standard 1-Must be easily obtained in very high grade of purity and of known composition. 2-Very stable, and resists reactions with air ( non-hygroscopic ) 3- It is recommended to have high equivalent weight to minimize weighing error. 4- It must react with other substances in quantitative way according to balanced chemical equations (stoichiometry) 1-The concentration of which can’t be directly calculated from the weight of the solute and volume of the solution. 2- The exact concentration is determined by: - Titration against a primary standard solution Dr. Hadir Shalaby

Examples: Standard solution Primary standard Secondary standard Acids potassium acid phthalate, oxalic acid, benzoic acid, sulphamic acid. Borax, sodium carbonate. Potassium dichromate, potassium bromate and potassium iodate. Sodium oxalate, arsenious oxide, and potassium ferrocyanide. Hydrochloric acid, sulphuric acid. Sodium hydroxide, ammonia Potassium permanganate Bases Oxidizing agents Sodium hydroxide takes up water and CO2 from the air Reducing agents Dr. Hadir Shalaby

Equivalence point: End point: The point in a titration when the amount of added standard reagent is exactly equal to ( is chemically equivalent to) the amount of the analyte. The point in a titration when a physical change occurs that is associated with the condition of chemical equivalence. The point in a titration at which no more titrant should be added( the reaction completed), It is determined by a color change in an indicator or by the appearance of a precipitate Volume difference between the equivalence point and the end point should be small . This difference in volume is the titration error

Detection of the end point Indicator : a substance that indicate the presence, absence, or concentration of another substance ,,often used in a titration to indicate the point at which the reaction is complete by means of a characteristic change, especially in color such as: litmus paper in acid media in base media Some titrants can be used as self indicators. e.g. KMnO4.

Methods of expressing concentration of standard solutions I-Molarity Molar solution: It is a solution of the substance containing one mole (gram molecular weight) of the substance per one liter of solution. Molarity (M) : It is the number of moles (gram molecular weight )of solute per one liter of solution. Dr. Hadir Shalaby

Some useful algebraic relationships: M = no. moles solute V( L) No. of moles = M x V ( L ) No. of moles = wt.solute, g fwt M=Molarity V=volume in liter Fwt= formula weight or molecular weight ( g) Dr. Hadir Shalaby

Examples: Example 1: Calculate the molarity of 17g Na2CO3 in 500ml of solution (fwt=106) M= …… wtg …….. = 17 = 0.320 fwt × VL 106 × 0.5 Example 2: ( HOME WORK) Calculate the weight in grams of Na2CO3 required to prepare 250ml of 0.15M solution. (fwt=106) Convert 500 ml to liter by ÷1000 = 0.5 L Dr. Hadir Shalaby

II-Normality II. Normal solution: Normality (N) : It is the solution that contains one gram equivalent weight of solute per liter of solution. Normality (N) : It is the number of equivalents (gram equivalent weight) per liter of solution. If the equivalent weight = formula weight so, N = M Dr. Hadir Shalaby

N=nM n (no. of (H+) OR (OH-) ) Normality (N) = Number of equivelant weight Volume(V) in (Liter) No.of eq.wt = N x V(L) OR \ No.of eq.wt = weight of solute (g) equivalent weight (Eq.wt) Eq.wt = Formula weight (F.wt ) n (no. of (H+) OR (OH-) ) N=Normality n = number of (H+) or (OH-) M= Molarity N=nM Dr. Hadir Shalaby

Calculate the eq.wt for each of the following: Problem??? Calculate the eq.wt for each of the following: HCl , H2SO4 , H2CO3 , H3PO4 , Ba(OH)2 *In case of HCl or NaOH HCl  1 H+ eqwt = fwt / 1 NaOH  1 OH- *In case of Ba(OH)2 Ba(OH)2  2 OH- eqwt = fwt / 2 *In case of H3PO4 H3PO4  H2PO4- + H+ eqwt = fwt / 1 H3PO4  HPO4-2 + 2 H+ eqwt = fwt / 2 Dr. Hadir Shalaby

Examples: 1-How much primary standard potassium acid phthalate, KHC8H4O4, is required to prepare 499.5 ml of 0.10 N solution?(fwt = 204.23) Weight ( g) = ?? No of eq.wt = N x V (L) Wt/ eqwt = N x V Wt ( g) = N x V x eqwt = 0.1 x 0.4995 x 204.23 = 10. 20 g KHC8H4O4 Convert 499.5 ml to Liter by ÷1000 = 0.4995 L Dr. Hadir Shalaby

TYPES OF WATER USED: Distilled water: is water that has many of its impurities removed through distillation Deionized water : is water that has had all minerals removed from it,as cations like sodium, calcium, iron, and copper, and anions such as chloride and sulfate, using an ion exchange process Deionized water (demineralized water): Distillation is a process where water is boiled and then the steam that rises from the boiling water is then cooled (condensed). The condensed water (called condensate) is largely free of any "impurities" (chemicals, etc.) that were present in the water before it was distilled. If water is distilled, and re-distilled a few more times, it is considered very pure water. Deionized water is water that was probably passed through several filters that have a slight electrical charge in the filter particles. This "charge" attracts ions (charged particles dissolved in the water). The purest of the pure water is used for very special scientific experiments is free of both ions (via deionization) and distillation (chemical impurities). To make such water, it is usually first deionized, then distilled.

Lab glassware and equipment

burette

Pipette: Graduated pipettes Volumetric pipettes graduated pipette: calibrated tube used in laboratory to measure the volume or transfer a particular quantity of liquid from one container to another

beaker

cylinder

funnels

Volumetric flask

Conical flask: Glass stopper conical flask Conical flask

Glass rod

Mortar and pestle

Hot plate

electronic balance

hood

GENERAL GUIDELINES: 1- When first entering the lab , do not touch any equipment, chemicals, or other materials in the laboratory area until you are instructed to do so 2- Follow all written and verbal instructions carefully.  If you do not understand a direction or part of a procedure, ASK YOUR TEACHER BEFORE PROCEEDING WITH THE ACTIVITY 3- Never work alone in the laboratory,No student may work in the laboratory without the presence of the teacher

4- Do not eat food, drink beverages, or chew gum in the laboratory,Do not use laboratory glassware as containers for food or beverages 5- Observe good housekeeping practices , Work areas should be kept clean at all times

7- Labels and equipment instructions must be read carefully before use 8- Keep hands away from face, eyes, mouth, and body while using chemicals , Wash your hands with soap and water after performing all experiments

9-you should Know the locations and operating procedures of all safety equipment

CLOTHING: Dress properly during a laboratory activity. Long hair must be tied back, Shoes must completely cover the foot

HANDLING CHEMICALS: 1- All chemicals in the laboratory are to be considered dangerous. Avoid handling chemicals with fingers , Do not taste or smell any chemicals 2- Check the label on all chemical bottles twice before removing any of the contents 3- Never return unused chemicals to their original container, and Never remove chemicals or other materials from the laboratory area

HANDLING GLASSWARE AND EQUIPMENT: 1- Never handle broken glass with your hands , Place broken glass in the sharps container 2- Examine glassware before each use 3- Never look into a container that is being heated 4- hood (how can we use it in the safe way )

Course syllabus:

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