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Extraction Lecture 11 Associate prof . L.V. Vronska

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1 Extraction Lecture 11 Associate prof . L.V. Vronska
Associate prof . M.M. Mykhalkiv

2 Outline Extraction. Substance distribution between two liquids.
The main quantitative characteristics of extraction. Types of extraction systems. The main organic reagents which use in extraction method. Usage of extraction in the drug analysis.

3 1. Extraction. Substance distribution between two liquids.
Extraction – is the process by which a solute is transferred from one phase to a new phase. Liquid-liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent. Аaq  Аor

4 Separatory funnel for use in a liquid–liquid extraction.
Process of dissolved substance transferring from one phase to another phase, which are immiscible or restrictedly miscible, is named liquid-liquid –partition or partition between two phase of liquids. Separatory funnel for use in a liquid–liquid extraction.

5 Two phase system, hydrophobic (top) and hydrophilic (bottom) for measuring the partition coefficient of compounds.

6 Solid-phase extraction cartridges: (a) disk cartridge; (b) column cartridge.

7 Partition law of Nernst – Shilov:
The relationship of dissolved substance concentration in both phases at constant temperature is constant and does not depend on concentration of the dissolved substance: D = CAorg  CAaqu D – the distribution ratio remains constant if there are no processes: dissociation or association polymerisation or other transformations of the dissolved substance

8 The ratio of substance activity in one certain form in organic solvent phase to its activity in a water phase is named a distribution constant The distribution ratio and constant are connected with substance solubility

9 Main concepts: Extraction is process of transferring substance of a water phase in organic Extraction reagent is reagent which with investigated substance forms compound which then is extracted Extragent is organic solvent which is used for extraction Latent solvent Extract - is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol or water. Extracts may be sold as tinctures or in powder form Re-extraction is process of transferring substance of organic phase in water Re-extragent

10 Conditions of a choice of solvent which is used as extragent:
1. Should not mix up with water. 2. Should be selective. 3. Should have the big capacity in relation to extractive. 4. The density of extragent should be difference from water density. 5. Should have the minimum viscosity. 6. Should be inexpensive. 7. Cannot be explosive.

11 Classification extraction processes:
Periodical extraction - is the process in which separatory funnel (which contain substance which extragent) is shaked Continuous extraction Countercurrent extraction

12 Schematic diagram of a Soxhlet extractor.
1: Stirrer bar/anti-bumping granules 2: Still pot (extraction pot) - still pot should not be overfilled and the volume of solvent in the still pot should be 3 to 4 times the volume of the soxhlet chamber. 3: Distillation path 4: Soxhlet Thimble 5: Extraction solid (residue solid) 6: Syphon arm inlet 7: Syphon arm outlet 8: Expansion adapter 9: Condenser 10: Cooling water in 11: Cooling water out

13 Schematic diagram of a Soxhlet extractor.

14 2. The main quantitative characteristics of extraction.
Factor or extraction efficiency R = ν (A) / ν (A)o where ν (A) – moles of solute in organic phase ν (A)o – moles of solute initially present in water phase Extraction efficiency for single extraction

15 Extraction efficiency:
for multiple (m) extraction Separation coefficient (factor) of A, B ions equal relationship the distribution ratio this ions

16 Enrichment factor (S)

17 Mn++n(HL)O=(MLn)o+nH+
Extraction constant for process: Mn++n(HL)O=(MLn)o+nH+

18 Extraction constant is function from:
formation constant of complex, which is extracted () Acid dissociation constant of extraction reagent if it forms extraction compound () Distribution ratios of extraction reagent () Distribution ratios of extraction complex () рН of medium (optimum)

19 3. Types of extraction systems
1. Halogenides with covalent linkage: HgCl2, HgJ2, SbJ3, AsBr3, GeCl4, element iodine etc. 2. Intracomplex salts: dithizonate, dithiocarbamates, oxyquinolines, oxyns, β-diketonate, and also di-(2-ethylhexyl)-phosphates actinoids, rare-earth and some other elements, etc. 3. Complex metal acids: HFeCl4, HІnBr4, HSbCl6, etc.

20 4. coordinatively not solvated (a) and coordinatively solvated (b) salts:
a) Salts tetraphenyl arsonium, tetraphenyl phosphonium etc. b) The compounds which is formed at extraction uranyl nitrate and nitrate of thorium by tributyl phosphate from nitrate solutions. 5. heteropoly compounds of phosphorus, arsenic, silicon, vanadium, molybdenum, tungsten etc. !!!! Most widely is used in extraction process intracomplex salts, complex metalo halogenide acids and coordinatively solvated (b) salts

21 4. The main organic reagents which use in extraction method.
8-oxyquinoline reacts with more than 50 elements Acetylacetonate forms compound with more than 60 elements Thionyl trifluoride acetone is used for excretion and separation actinoids. dithizon is used for determination of Pd, Au, Hg, Ag, Cu, Bi, Pt, In, Zn, Cd, Co, etc. !!! It is of great importance in the toxicological analysis. Sodium diethyl dithiocarbamate reacts with several tens of elements

22 For increase of selectivity extraction:
Create optimum рН medium Use masking (reactions of complexation, oxidation-reduction, precipitation)

23 5. Usage of extraction in the drug analysis
Extraction is used for: Separation of elements Concentrating impurities Clearings of the basic component from impurities in the process of synthesis of substances of drugs Definition of the basic component from impurities in the process of synthesis of substances of drugs

24 For identification and quantitative definition of chemical agent or substances-markers in the process of the analysis of phytogenesis drugs Increase of sensitivity and selectivity of reactions Studying of formation constant of complexs Studying of substance condition in a solution (a charge, polymerisation degree) Reception of extracts, tinctures, fermental preparations, antibiotics, preparations from a different biological material.

25 Usage of extraction as method of concentrating and definition
Absolute concentrating is reached at usage of smaller volume of an organic phase in relation to initial volume of a water solution. Relative concentrating is an increase in impurity concentration in relation to the main component. Especially important role extraction is by connection with physical and physical-chemical methods of the analysis - hybrid methods of the analysis which have such advantages: High sensitivity Selectivity Specificity rapid analysis method

26 Extraction of medicinal herbs includes stages:
Drying (sometimes it is not necessary) Crumbling up Sifting Selection of optimum extragent Choice of an optimum technique extraction Extraction (moisten, passage extragent through pores, dissolution of substances in the middle of cell, diffusion of substance molecules through cellular covers, mass-carrying extraction substances from a surface of particles in extragent).

27 Analytical techniques of reception of an extract for the purpose of medicinal herbs analysis on high quality: Extraction to a full attrition (percolation with 1 g medicinal herbs through burret) Single extraction of raw material shot (by boiling 1 g raw materials with extragent) Equilibrium extraction (for 4-5 hour balance between internal extrageny in medicinal herbs and the external extract, analyzes an extract part) !!! In the biochemical and toxicological analysis extraction is used for excretion of substances from animal and herb tissues, as fresh and dried up.

28 Rotary evaporator

29 Thanks for your attention!

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